Hello? Anybody hear me? All righty. How's everybody doing today? Good. This is an interactive session. It's the first of, hopefully, many interactive sessions. But we've got to get the energy up in the room. It's a little bit different. It is stateful sets on Kubernetes, the guardians of your data galaxy. So already, you're starting to see a little bit of out of the norm talk here. So hopefully, it'll be a little bit of fun. So let me start. My name is Eddie Wasif. For those of you who don't know, that's a Dallas Cowboys uniform. I come from Dallas, Texas. Or I am from Dallas, Texas. Woo-hoo! All the Dallas folks out there. Tough game. Tough game yesterday. We didn't pay off the refs enough. We needed to, but we lost to that. It was unfortunate. But before tech, I was going to be a Dallas Cowboy. Fortunately, I had a career-ending injury. I was born too short, too slow, and not very good at football. So I got into tech. I got into tech. And that's how that happened. And I'm sticking to that story. I'm a husband to a beautiful wife, Besma. Thank you for letting me come. She's going to watch this later. I have two beautiful boys. I develop and I architect. Been doing it for about 23 years. So yeah, that's a little bit about me. I love open source. I didn't always love open source. I used to think that was how I made money. So why would I give it away for free? But I've changed my ways. I love open source. I contribute to open source. I speak about open source and different products and stuff like that. So I've come a long way. I hunt and I fish very expensive hobbies. So I do this to pay for that. So holidays are coming up. So I got to do the speaker circuit to buy more fishing lures. They're very expensive. What else? Being from Texas, I barbecue, I grill. We make a mean brisket. And like many of you during the pandemic, I picked up a sourdough, but I was never very good. And I ended up doing sous vide instead. And then finally, last but not least, I'm a VP and chief architect at Vonage, which is an Erickson company. We deal with communication. Many of you have heard about us in the landline world, but we do SMS, video, voice, network APIs, and so many other things. We deal with a lot of data. We have lots of billions of minutes of voice and video and SMSes and so on. Do come scan this QR code. We've got all my information here. Now you can connect to me. And speaking of that, we all produce a ton of data every day, every minute. We produce about just shy of 2 megabytes of data a second. Think about that. That's a lot of data a second. That's almost 150 gigs a day. And it's estimated that on the whole world collectively, produces about 330 million terabytes of data. And I didn't know this new metric, but apparently 1,000 million terabytes is a zettabyte. And that's how much data the world produces a month, a week, and a day. And that is not just for shock value. Let's think about that for a second. You may not be producing contextual data about yourself, but you're producing logs. If you have a smart phone, smart watches, smart glasses, like the ones I'm wearing, they're calling home, that's creating a log record. Your phone is getting GPS data. That's logs. Every time you go and you scan that QR code to look me up on LinkedIn, you're creating more data. You're creating more context. You're creating more things that are being stored somewhere. When you post pictures or you tweet, or I don't know if we're calling it a tweet or a few X or whatever it is today, you're creating data. And that's a lot of data that's being produced. And I argue that because we're able to collect this data and take that data, turn it into information and to knowledge and add context to it, that's what's driven really the technological advances that we've had in the last two decades. Because all that data is gone. But we can use that data to really move us forward. When your TV knows what shows you're going to like, before you know what shows you're going to like, it's because of data. When you are looking to see how you're going to get to your hotel and there's traffic on the map, that's data. All of this is data that's really driven the technology and our whole life, really, is because of dealing with all that data. Well, we are in a Kubernetes world. And we use Kubernetes every single day because it's great. We're at a Kubernetes conference. And you don't usually hear about data or you don't see people advocate for data on Kubernetes. I don't know why. And if you look at Kubernetes, Kubernetes is great. It gives us efficiencies on our infrastructure because it lets us auto-scale. It has self-healing. It has the ability to pack machines properly. It really creates an abstraction, lets you deal with your infrastructure very efficiently. It also gives the developers a lot of freedom and enhances their productivity. There's a whole backstage con and a whole developer going on about all the things that have been enabled because you don't have to worry about infrastructure anymore. You don't have to worry about what kind of machine I'm running on. If it runs in a container, you can define a YAML file and just worry about making your application the best it could be. It also lets you scale very easily. I'm going to do a quick poll here. How many of y'all say KubeCuttle? How many say KubeControl? And how many say KubeCTL? Hands up for KubeCuttle. How many hands up for KubeControl? Hands up for KubeCTL. Wow. How many of you, like me, have left it and just created an alias called K and just say Kscale? All right, there we go. I think we've got a tie, I think, between the two. But really, it's a one-liner. You can, through the CLI, scale your stateless applications very easily. Scale them up and down. You have tools like KDA. You can scale in and out on whatever you want. Very, very easy to do. It also has a very high resiliency. You can remove a pod. It'll come back up somewhere else. You don't have to worry about it. You don't have to have alarms or anything. Half of the time when we're fixing a problem, we kill the pod. And it just fixes itself. You don't have to worry about all the things that we used to worry about back in the day. It's also vendor-neutral. And that isn't necessarily to mean that anybody is, you're going to forget about the big guys. But it's about leveling the playing field. We have a dozen vendors that do the same thing. And you're really going to start looking at the merits and what fits you the best. And that is one of the things that Kubernetes has given us, is the ability to be vendor-neutral and really level the playing field. Consistency between installs, your dev, QA, prod, demo, staging, whatever it is, it's the same YAML file. It works on your machine. It works on that machine. It works in every other environment. And then options, right? There are 5,000 of us here at KubeCon. Hundreds, maybe even more vendors. You have lots of options. You can pick anything you want to do a lot of the same things, whatever fits your use case or your budget, or whatever things you have. You have so many different options for you to be able to enhance your applications. And so why have we not done this as much with stateful applications, right? And if you think about it, let's think about 10 years ago how our databases were, how our data-intensive applications were. There was a server in that corner over there that had dust on it that nobody was allowed to come within 10 feet of, right? And there was a curmudgeon that sat in the closet that couldn't take vacations, and he was the only person that knew how to run that machine. And that's how we did data for a very long time. Tell you a story, we had a Solaris database that we needed to move from Ann Arbor to Las Vegas. And we literally hired a truck that had special shocks and special AC unit and a special battery where they came and they took this server while it's running, put it in this truck, and drove it like we were driving the president all the way to Las Vegas to plug it back in. You don't need to do that anymore, right? And I'm gonna give you a little bit of why I'm an advocate of not doing that anymore. And if you guys haven't gathered, I'm not conventional, right? I like to think about things in different ways and in different parallels, and hopefully you got a taste of that from the title of this talk. But one of the things I'll tell you a funny story, I was speaking in Microsoft, and I'd never been to Seattle, and I saw a sign that said, respect the semaphore. And I was like, oh, look, it's a dev town, they're using semaphore. Apparently, semaphore comes from real life and we used it in code, right? I had no idea that you can get a ticket for violating a semaphore. It's not a threading thing, it's a traffic thing. But so there's parallels in the tech world to the real world. And I like to make parallels to the fantasy world. So I'm gonna take you on a little bit of a fantasy trip here. We're gonna live in the Marvel world or the Marvel Cinematic Universe a little bit. And we're gonna talk about Kubernetes being our Marvel universe.  They're great, they do their job great. And we're all pods and when they save us, we're just numbers, all right? So we need the unconventional Avenger that's gonna help us with our data-based or our data-intensive applications. And that Avenger is our stateful sets. Any guesses on who you guys think the Avenger is that's gonna be stateful sets? Star Lord. All right, Star Lord, for those of you who are not familiar with the universe is a half human, half planet. His dad's a planet, I guess. But he was stolen after his mom passed away. He lived with the ravengers. He was uprooted. He has a very quirky personality. He does things a little bit different, right? And what he does is he feels for the pods that have data. Just like him, he was uprooted and moved around. So he doesn't give them a number. He gives them a name, right? And he sticks that name to them. So they have an identity. They're not just number A, B, C, or X, Y, Z. They're pod zero, pod one, pod two. And that gives them a network identity for your data applications to be able to continually refer to each other through that name. It's not a number anymore. It's giving them personality. It also cares about seniority. If you've been with Star Lord for a while and we need to move, or there's too many people in this room, he's not gonna kick the first one out. Seniority matters. So it's gonna be ordered in how pods are upgraded. It's gonna be ordered in how pods are evicted, right? And that's because he's treating pods as if they were people with names, very personable.   And so he tries to keep you as stable as possible. Evictions are not gonna happen the way they do with deployments. You're gonna try to, he's gonna try to keep you in that bunk bed as long as you can with your bags. And so that's some of the cool things that stateful sets give you. The other thing is he still is an Avenger. So all of your pod lifecycle events, all of the everything else that you do with templates, everything that you're familiar with on your pods are still applicable with your stateful set. Plus a little bit more, plus the stable network identities, plus the ordered deployments, plus the stickiness of that capabilities there. So that's great. Now we've gotta handle or deal with the data, right? We gotta deal with the suitcase that each of them brought with them, right? It's not just a fanny pack or their wallet and their keys and they can go. We gotta deal with their data. And that's in the Kubernetes world, persistent volumes. Any idea who this Guardian is gonna be? I am Groot is who I think persistent volumes is represented by, right? And Groot for those of you who are not familiar is a big tree-like structure.  So I hope you're starting to see a little bit of how they're related in that aspect. So they're very dependable, he's very dependable. Groot is someone you can rely on, he's gonna be there, if the node is lost, persistent volumes don't care about the node, they're usually with some other storage and they can be part of the cloud infrastructure or your storage infrastructure and they are separate. Your node can go away and then when the new node comes back it'll attach that same data, so your data's safe, right? It's adaptable, right? You wanna have a little baby Groot, that's fine, small amount of data and that grows with you and it becomes teenage Groot, it becomes adult Groot. And Groot can be fast or it can be slow. It could be the very slow kind of storage or it could be the really fast in the latest movie where he's just shooting everybody up, right? So it adapts to all different kinds of things to handle that kind of data and to handle the needs that you have your application. The other thing is Groot can come back, right?  But there's a problem with Groot, right? All he says is I am Groot, just like storage. Dealing with storage is very, very complicated, very difficult. Are you gonna do replication?  How are you gonna claim it, all of this stuff? So we need something to help us translate and those are our storage classes. Last chance, who do y'all think this is gonna be? Huh? Rocket raccoon, that's exactly right. Right, he is the guardian that can understand Groot and can do all the automation and helps us talk to Groot so that we can provision the storage wherever we want. He's a cool little buddy and by the way, all of this is AI generated because of all the data that we've gathered through all the different movies, all the different comic books. I just asked Bing here for a cool, epic rocket raccoon pose and so on and so forth so that's a little bit of what data can give us. But let's talk about what the benefits of a storage class are, is that it speaks Groot's language, right? I am Groot, I am Groot, but that could be, I am Groot, I need multi-replica data or I need fast provisioning or I need provisioned IOPS or I need to be on a NAS or I need to be whatever. We don't need to worry about that. We're talking to Rocket raccoon. We just say, hey man, give me some fast storage or hey, give me some replicated storage.  If you guys watch the movies, he can fly anything. He can tinker with any machine. He can provision you EBS volumes. He can provision you Azure disks. He can provision you NAS storage. You just ask them to do it and the storage class will go ahead and figure out how that's done and hand you your volume on a plate, right? He's very flexible, like we mentioned, right? Where he can take a snapshot, right? He can work with taking that splinter from Groot and he can turn that into a whole other persistent volume and give you more storage or expand your storage and it's all very simple and very transparent to the application. So hopefully we're not gonna go too much more. There's a lot of additional guardians and a lot of additional things, but for the interest of time, I really wanna kinda sum back up and say, look, now we have the Guardians of the Galaxy available for us in our Kubernetes environment. We should be able to recognize that we can do everything that we've done with Kubernetes from for our stateful applications, right? There is nothing that's preventing us from running our Postgres MySQL or Microsoft SQL Server or CockroachDB or any kind of RDBMS, right? When we use stateful sets and persistent volumes and so on, we see that it's safe. We have the Guardians of the Galaxy protecting that data. There's so many different kinds of things, right? You can have no SQL databases, Mongo, Redis. You can have big data. You can have IoT, large language models. You can have anything that you need data. You should feel confident being able to do that and I'll give you an example of why we should think about our databases like microservices. We have Black Friday coming up, right? Who's already started chopping? There you go, me and you both, right? But in a few weeks, things are gonna go nuts and we usually think about sealing our web servers and that's because our database servers are probably very much over provisioned already but you can take the same concepts now with Kubernetes and apply them to your stateful applications. Why can't we provision large specialized machines just for the two weeks, a week before Black Friday and a week after? And then we can cordon and drain the nodes, move our data safely. Now we know it's very safe to move it, right? And now you can scale up instead of just out. For two weeks, save yourself the cost of having those really expensive servers all year long just for the two weeks that you're running Black Friday and you know about it. Use a Cata autoscaler for a cron job or use some other metric and now you've handled and scaled up to Black Friday without having to bust your budget. You can do things like, because you're in Kubernetes, you can emit custom events. You can capture any kind of pod lifecycle event where you are publishing, hey, I'm going down. Instead of waiting for whoever your leader is in your database service to figure out who's going to go down and we got to figure out what to do, they're going to tell you through an emitted event or through using some kind of metric that you can emit onto the Kubernetes event backbone. So hopefully, like me, I'm no longer scared to put data in Kubernetes. I actually encourage it and I think it's the way to go because we can use all of the things that all of us every single day use with our stateful applications to make our data applications even better and we can use it in a way that is safe and resilient and fun, hopefully for all of us. Okay, with that I'm going to wrap up and take questions. Thank you so much. Please go scan this. I hear there's a bug. You have to give like five stars to this talk for it to close. That's what I heard. It may or may not be true but we have five minutes left and I'm more than happy to answer any questions. If you have a question, you can go up to the mic or raise your hand and I can bring the mic to you. I hope you all had fun. Who had fun? I had fun, thank you. There we have a question over here. Come on up. Jump up to the mic. My question is right, I want to ask what's the largest amount of data? Can you speak up just a bit? My question is, I wanted to ask what's the largest amount of data you've seen organizations storing on Kubernetes, right? The largest amount of data I have seen organizations store in Kubernetes? So terabytes of data. A lot of the newer generation database systems can actually shard the data and store portions of it in different locations. And so it's not like a traditional database where you just have one giant persistent volume, you can have dozens of 10 terabyte persistent volumes around. We have a couple of different, we do micro database structures because we deploy a database where every team or every app. And we have probably our biggest is 15 terabytes worth of data, no problem. It's a really interesting question because one of the things that I've personally discovered when we've introduced micro databases to our teams is that the way that you look about sizing is very different because you're treating your database as a microservice and every particular nodes have their own attached storage, you are not calculating the size of the database the same. And if you need to scale, you don't necessarily scale your persistent volume, you add additional nodes or additional servers, right? And a lot of times that's hard to understand, right? So let's say for example, we have a one gig persistent volume per node, you have a four node cluster, that's four gigs. How do you increase that? Do we go to each one and make it two gigs or do we just add another node by doing a K scale set replicas to five? Both will work. One will give you an additional gig and the other will give you four additional gigs. And so those are kind of the things that when you start thinking about data as a microservice, whether that's a database or a message queue or so on, it really starts changing the dynamic of how you size, how you tune, right? And how you migrate data and schema across. You have another question back there. Yeah, thanks for bringing up the Star-Lawded Racket Raccoon. I see the stateful sets, persistent volumes and storage classes really fit into the big picture of managing data on a specific cluster. But now we are looking at geo-distributed multi-cluster databases, right? So they're all like you mentioned, so many options. So what's your take on that in case of... So you have options to go directly, directly over network load balancers. You have options to go over service meshes or virtual application networks. My personal preference, and this is purely my personal opinion, I prefer virtual application networks. And we use tools like LinkerD and Scupper to create a transparent virtual application network between our database nodes. What that lets us do is it effectively creates a replica foe stateful set, right? That's pointed to a bunch of routers and they all think they're on the same cluster but they're really somewhere else in the world. We also use CropCoachDB. We have geo pinning for data. And so that's some of the things that we utilize for like GDPR or CCPA or any other kind of compliance or other issues. That's, you can use those tools in a cloud native way with a virtual application network. So that's just my personal preference on that. We've looked at Istio service mesh. The question is, have we considered Istio service mesh? And we did, Istio is very powerful, very, very powerful, very, very complicated, right? And we found that using a virtual application network where basically you were just using DNS and a headless service was much easier to configure. And because we're doing a micro database and micro cluster segmentation, it just was a lot of less effort for us. But Istio is a fantastic option. And I know that they do that. I know with Anthos, you can do it. I know Azure Arc has a solution that is very similar as well. So no problem. Thank you for the question. Thank you so much. Thank y'all. That was my time. Thank you.


With that said, I'm going to take you into our study Mark chapter 13 verses 32 through 37 Beginning at verse 32 Jesus said but of that day and hour no one knows Not even the angels in heaven nor the Son, but only the Father Take heed and watch and pray for you do not know when the time is it is like a man going to a far country Who left his house and gave authority to his servants and to each his work and Commanded the doorkeeper to watch Watch therefore for you do not know when the master of the house is coming in the evening at midnight at the coin of the rooster Or in the morning Let's coming suddenly he finds you sleeping and What I say to you I say to all watch and So let me give to you as I normally do a synopsis an introduction a review so we can come to this passage with understanding we've been studying chapter 13 and we've been studying Jesus's answer that had been asked to him by his men as Jesus and his men were leaving the temple his men had noted the beauty of the temple in verse 1 of Chapter 13 they had said teacher Behold or see what manner of stones and buildings are here. I Mentioned this to you, but the temple was the center of Jewish life as a building. It was incredibly beautiful At this time construction had been going on as they were rebuilding the temple It had actually been worked on And additional buildings had been added and repairs had been made over the span of 46 years and so because of this It was magnificent to look upon it was breathtaking and because it was Jesus's disciples called his attention to it And his response must have absolutely surprised them because in verse 2 he had said do you see these great buildings? Not one stone shall be left upon another that shall not be thrown down So his response provoked the disciples to ask well, when will these things be what will be the sign when all these things will be Fulfilled so the entire 13th chapter of mark is really the answer to those questions So as we've been going through the chapter, I've noted with you how that Jesus outlined the conditions concerning his coming There's going to be a period of general tribulation that occurs during what is called the church age the age that we're in now But after the rapture of the church the tribulation will begin with escalating judgments for the first three and a half years The abomination of desolation will occur in the middle of the tribulation and then the great tribulation ensues from that point And at the conclusion of the seven-year period Jesus will return so in our last study we saw how Jesus spoke concerning his second coming He had said be ready to those who are alive in those days when they saw these things He was speaking of those who were going through the tribulation and it would would endure and come to the end of it And so he had said to them be ready in verse 28 He said that summer is near in other words when these things take place his return will be soon in Verse 31 he had made it clear that his return was certain and it was guaranteed by the word of God Like it says in the book of Isaiah 40 verse 8 how the grass withers the flower fades, but the word of our God stands forever For us these words are instructive They're to inspire dedication and and faith it gives us hope in the midst of so much evil that we live in in our world every day For those who are alive when these things are occurring his words are supposed to inspire Urgency with so much deception and judgment there to be on the alert So as we look at these verses Jesus uses the word watch four times in verse 33 notice He says take heed and watch in verse 34 the man commanded the doorkeeper to watch in verse 35 Watch therefore and in verse 37. He closes by saying watch And so Jesus is speaking concerning the conditions prior to his second coming and the conditions that are leading up to it And so as he's continuing and teaching in verse 32 He says but of that day and hour no one knows not even the angels in heaven nor the Son But only the Father The exact moment of his return in other words is unknown to man or to angels No one can predict the date of his return. Why because his date is not revealed in Scripture There will be visible signs that his return is approaching But those signs should be causing people to be prepared for his return But the precise moment is something he says that only the Father knows Notice verse 32 how he says of that day and hour no one knows in spite of that in spite of Jesus pointing that out no one knows people still try to guess the date I Could give you so many examples But a couple of them come to mind and I'll share these with you because there have been various Individuals who've actually written books. They've written books trying to guess when this is going to happen All the way back in 1988 before many of you were born There was a guy named Edgar Weisenand and he wrote a book. It was called 88 reasons why the rapture will be in 1988 He said Jesus would return between September 11th and September 13th during Rosh Hashanah or the Jewish New Year Well when it didn't happen the next year he wrote another book 89 reasons Jesus will return in 1989 There's a fellow some of you perhaps has heard have heard his name his name is Harold Camping and Harold Camping wrote a book saying that Jesus would return in 1994 he repeatedly said he was 99 percent sure Jesus would return in 1994 but obviously was wrong You see every time something like this happens It undermines the credibility of the gospel of Jesus Christ, but it also undermines the faith of innocent and trusting believers the Apostle Paul when he was writing to the Church of Rome in Chapter 16 verses 17 and 18 said this he said to the the leadership there I urge you brothers and sisters to watch out for those who cause divisions and put obstacles in your way that are Contrary to the teaching you have learned keep away from them for such people are not serving our Lord Christ But their own appetites by smooth talk and flattery. They deceive the minds of naive people Those who are are Innocent those who have a naivete those of who are just wanting to believe in that and I'm trusting this minister Well, well Paul says be aware of them note them mark them stay away from them Why because they're deceiving and undermining the faith of those who are weak or still immature? That kind of a thing can undermine our expectation that he's actually going to return So it has to it has to be dealt with because it undermines faith and and therefore must be avoided You see the church has been instructed to live as if Jesus is returning even today We're supposed to live as if he's coming today various scriptures reveal that Jesus can come at any moment Paul when he was writing to Corinthians in 1st Corinthians 729 said it like this He said this I say brethren the time is short in 1st Corinthians 10 verse 11 All these things happen to them as examples. They were written for our admonition upon whom the ends of the ages have come Philippians 4 verse 5 let your gentleness be known to all men the Lord he says is at hand So the understanding that the time is short the Lord is at hand is actually to encourage us to live for Christ to encourage believers in Jesus to live a holy life and so Jesus is speaking about that, but he makes the clear in verse 32 again of that day and hour No one knows so don't be predicting dates. Don't be undermining people's faith He continues and he says neither the angels of heaven. No one knows neither the angels of heaven Now that's a significant thing for him to say because angels are heavily involved in the second coming of Jesus They return with him according to Matthew 1627 there it says the son of man is going to come in his father's glory with his angels and then he'll reward each person according to what he's done in Matthew 2531 when the son of man comes in his glory and all the holy angels with him then he will sit on the throne of His glory angels are involved They return with him and not only that but they're used to separate the saved from the unsaved according to Matthew Verses 39 through 42 Jesus said the harvest is the end of the age the harvesters are angels as the weeds are pulled up and burned in the fire So will be at the end of the age the son of man will send out his angels And they will weed out his kingdom out of his kingdom everything that causes sin and all who do evil They will throw them into the fiery furnace where there will be weeping and gnashing of teeth These angels as scripture says are heavily involved and yet they do not know when this is going to take place They don't know the exact time. It's interesting how in verse 32. He said no one knows Including the son of man including himself Now this was spoken in view of his human nature It speaks of the fact that he voluntarily restricted his divine prerogatives Jesus had self-imposed restrictions on his human knowledge in John 15 verse 15 He said it like this. He said everything that I learned from my father. I have made known to you So Paul spoke of that in Philippians 2 5 through 7 when he said let this mind be in you Which was also in Christ Jesus who being in the form of God did not consider it robbery to be equal with God But made himself of no reputation Taking the form of a bond servant and coming in the likeness of man So during his incarnation the father alone has Unrestricted divine omniscience total knowledge Jesus lift limited his omniscience to what the father had revealed to him and in doing so He was submitting himself to his father's will and John 12 49 he said I've never spoken on my own initiative or authority But the father himself who sent me has given me a commandment regarding what to say and what to speak what to say and What to speak what to speak means and how to say it? But he said I didn't do this on my own initiative or authority, but the father gave me a commandment So when Jesus was resurrected he resumed his position in Matthew 28 18 It says Jesus came to them and said all authority in heaven and on earth has been given to me So his return is according to his father's timetable and plan. It wasn't disclosed to angels He wasn't disclosed to himself in Deuteronomy 29 29 It says the secret things belong to the Lord our God But the things revealed belong to us and to our children forever that we may follow all the words of this law There are secret things that are held back by the father and there are things that are revealed and that's why in verse 32 He says only the father Speaking of knowing the exact moment that he'll send his son again. That's intended to keep his disciples serving and waiting expectantly Zechariah 14 5 through 7 in the Old Testament says it like this Then the Lord my God will come and all the holy ones with him on that day There will be no light no cold or frost it will be a unique day with that daytime or nighttime a day Known to the Lord and so that is something that the father knows We're presently living in a general period that precedes his return the blossoming of the fig tree appears to have occurred when when the nation of Israel was reborn But with that said there remain specific events that are waiting We are waiting to transpire that would include the rapture of the church as well as a seven-year tribulation period So the signs that we've been looking at as we went through chapter 13 and all of those things are Indicating is to indicate to us the nearness of his return now. Why weren't we told the precise moment? I think part of the reason may be because we would be tempted to put off coming to faith in Christ to the last moment If I knew he was coming on such and so a date I could be tempted to just continue living in the world and then to just say well, he's coming back April, Trout or whatever I better get right with God now he wants us to be in a state of anticipation and There are those who would say well, you know, I'm gonna wait until the tribulation See what's really going on in that. Well, there's no guarantee that they could even make it through the tribulation There's going to be a lot of martyrs during that time and a lot of death and and all of that And so we aren't told the precise moment so we can live as if it's today Salvation isn't something by the way that you delay receiving Salvation is something you should receive immediately You don't wait till the last second. I Have never met anybody and I've been around for a while now. I have never met anybody who's come to faith in Christ I have never met anybody Who's ever told me perhaps you're in this room right now or watching, but I have never met anyone who has said to me I wish I would have waited longer I've just never met anybody who has ever said oh, I got saved too early. There was a lot of sinning I never got to enjoy I've never met anybody like that. I the only thing I've ever heard when people leave and speak in that way I've heard them say I wish I would have given my heart to Christ sooner. I Would have saved myself to be honest with you so much pain I would have saved my parents so much pain I would have saved my brother and my sister so much pain I would have saved the the people who are my friends so much pain that I brought into their life and so much hurt That I've that I brought into the lives of those that I said I cared about no I have for many years. I have said to myself would to God I would have come to faith sooner So I've never met anybody who has ever said I wish I would have waited a little bit longer in Second Corinthians chapter 6 verse 2. He says in the time of my favor. I heard you in the day of salvation I helped you I Tell you now is the time of God's favor now is the day of salvation For those who are putting it off those who are waiting now is the day not next week not next month not next year It's now and that's what the Apostle Paul pointed out and that's what God has said to us So if you've come to faith in Christ, it means that we're to be living in anticipation of the return of Christ And again, we should be hoping that it's even today in Romans 13 12 The night is nearly over the day has drawn near So let us lay aside the deeds of darkness and put on the armor of light in second Corinthians 7 verse 1 And therefore beloved since we have these promises Let us cleanse ourselves from everything that defiles body and spirit perfecting holiness in the fear of God We should be prepared and living in anticipation of the return of Jesus Christ hoping that it would even be today in the sense for us of the rapture and obviously those who are going through the tribulation They'll be living in anticipation of seeing him And so he says again in verse 32 of that day and hour no one knows Not even Harold camping not even the angels in heaven nor the son But only the father verse 33 he goes on to say take heed watch and pray for you do not know When the time is Notice how he says take heed watch and pray So he's issuing a command to followers. He's he's speaking to Christians take heed In other words be alert watch be ready for action. Pray depend on God When the Lord comes the ungodly will be forever swept away They will never again have the possibility of receiving Jesus Christ When you die unsaved you go into eternity unsaved there is no place in them in between your death and Standing before God where you are given a second chance Nowhere in scripture does it ever teach that you have an opportunity once you've died To come to faith in God nowhere. There are people who will say well Everybody eventually is going to stand before God and go to heaven There are teachings that that everybody is going to be saved But the Bible doesn't teach that man has invented that and So he tells believers he says take heed when he speaks of that he's speaking of being on the alert be on your guard Be discerning in other words. This requires personal attention It's your responsibility to be on the alert. This is necessary now. It will be necessary during the tribulation Now he's already spoken of taking heed in verse 5 when he had said take heed that no one deceives you Take heed speaks of personal responsibility. Well, I'm supposed to remain in the position of taking heed That's a responsibility of every believer during every age We're to exercise discernment to protect ourselves from deception and this discernment this alertness being awake Well, that comes from the Spirit of God and that comes from God's word In 1st John chapter 4 verse 1 John said dear friends do not believe every spirit tests the spirits to see whether they are from God because many false prophets have gone out into the world during the Tribulation there is the false prophet and many false prophets even today Many false prophets have gone out into the world denying Jesus Christ who bought us Denying that God took upon himself human flesh Denying the need for the cross or salvation by faith in him There are many false prophets who've gone out into the world and are deceiving many to this day That's why he says test the spirit you test the spirits through the discernment of the spirit But you also test the spirits by the word of God in 1st Thessalonians 5 20 and 21 He says do not treat prophecies with contempt, but test them all hold on to what is good So you test them by the word of God You see at that time during the tribulation when so much is going on Deception will be rampant. So it's important to stay alert to be awake to watch Now in verse 33 when he says to us watch the word watch speaks of staying awake It speaks of being on the alert. It speaks of being prepared for action The word watch is actually saying be sleepless. Don't go to sleep. I had a stand watch Every military veteran in this room probably knows exactly what that is I had to stand watch when I was in the army. They have you standing watch. You have to remain alert They'd get you up it for us if for me They woke me up at three in the morning and then they gave me a little an axe handle And I walked around the barracks and walked in certain perimeter I had to do that to be on the alert in case somebody would come on Come on Fort Orden and and Rob and that they would do that sometimes and and all of that We were told certain commands. You have to say certain things stop, you know, halt who goes there Identify yourself those kinds of things. I still remember I would for some reason this just came to mind So I'll tell you I got an old mind. It kind of hey remember that so anyway, I was I was in bed and I was at Fort Ord and we had to sleep with the windows open because of meningitis and So it was cold and but we have had to have the windows open I still remember I was I was in my bunk and I heard a guy right out my window right outside when my windows saying Halt who goes there?  That's what we were taught now. This guy's in basic training He says identify yourself and the guy says something back to him And so the guy who was given the commands hit the guy he hit the guy who was talking back to him He hit him with the axe handle. He hit him. I could hear a boom Then all of a sudden I hear ow ow ow ow Well the guy he had hit took the axe handle from him and beat him up outside my window I don't know why I'm telling you about anyway We we had to stand guard and it can be dangerous. You have to be alert I saw the guy the next day. He had his head wrapped up with bandages. He got There was a guy by the name of lieutenant Kelly. Some of you may remember that name it was associated with what is called the melee massacre where he had ordered his troops to massacre a particular village and It was a it's a war crime and he was he was in jail. He was jailed Fort Benning in Fort Benning, Georgia when I went to jump school part of what I had to do with some of the people is We had to guard the place that that Lieutenant Kelly was at we walked guard there. We guarded the perimeter You're you're told to be on the alert to be sleepless Because if you go to sleep and the enemy is coming or approaching He can devise that the enemy can devastate Your camp There's there's many stories of when that happened again during Vietnam when When they allowed the enemy combatants that allowed the American who was to be on watch They watched him as he went to sleep he fell asleep on guard and then they came in and killed all of his friends It's a very serious thing when you're told to be on the alert Beyond watch because danger is is approaching and so when Jesus is speaking in this way He's saying stay awake stay alert be prepared for action Be sleepless. He also goes on in verse 33 and he says pray depend on God maintain your fellowship seek the Lord for guidance as It says in Ephesians 6 18 Pray in the spirit at all times with every kind of prayer and petition to this end Stay alert with all perseverance in your prayers for all the saints Why is that verse 33 because you do not know when the time is? To be alert to watch and pray Requires faith and patience. He's coming, but he's coming in his own time He has not given us the exact moment therefore. We should be prepared as if he's coming at any moment We patiently wait for him The Apostle Peter in 2nd Peter 3 8 and 9 said it like this He said do not forget this one thing dear friends with the Lord today is like a thousand years and a thousand years Are like a day the Lord is not slow in keeping his promise as some understand slowness He's patient with you not wanting anyone to perish But everyone to come to repentance So to illustrate this Jesus tells a story He says in verse 34 it is like a man Going to a far country who left his house and and gave authority to his servants and to each his work And he commanded the doorkeeper to watch and So This rich man as we read he left his home and he was traveling But he left his home and entrusted his his servants to care for his home Now he fully expects them to perform the duties. He's entrusted to them He travels abroad, but he doesn't tell them when he's going to return Now the master we know in this story is Jesus who will soon be crucified His disciples are to carry on his work as he has gone until he returns So as believers were to be busy serving knowing that he will return So the church is to be in the state of readiness were to be awaiting him were to be watchful And and it's going to be a while before he returns and distractions will come Distractions happen our our lives are caught up with distractions And it's it just takes small things to awaken us to the reality of that. I'm watching a baseball game yesterday They call it a baseball game In my beloved Dodgers Oh No, no, no, no John would you please escort And and they lose It's a game But I didn't even want I didn't watch it past the seventh inning. I said I don't want to do this and Marie's just sitting there, you know, she usually goes to sleep anyway, but I'll wake her up and say I'm upset and I'll go back to sleep But you know how easy it is to be distracted It is it's easy. It's easy to be distracted. It's not like I'm supposed to be sitting there. Jesus. Are you coming right now? I'm not saying that it's just that I can I am my joy My happiness can be affected by the smallest things and the Lord has been trying to teach me to keep my eyes riveted on the eternal things And that's the way it's supposed to be right. So I'm supposed to be in the state of readiness I'm supposed to keep my mind on the things that ultimately really matter and it is going to be a while Until he returns and distractions. Yes, they come but notice in verse 34. He gave authority So the work that is done is through the authority of Jesus and and it's not authority We've assumed for our selves The work that is performed is what is revealing that we are his servants and notice in verse 34 How it says he gave authority and to each his work in other words Each servant has work to do. He's commanding the church to be busy serving him Until he returns like it says in 1st Peter 4 verse 10 as each one has received a gift Minister it to one another as good stewards of the manifold grace of God as Everyone as each one has received a gift. I was sharing with the first service this I'll repeat the same sentiment with you When you got saved when you got saved not only did you receive salvation? But when the Holy Spirit has indwelt to God is also given to you spiritual gifts Not only one gift, but most often you have what is called a gift mix meaning there are more than one gift There there's more than one gift that that the Lord has bestowed on you But every every believer has at least one gift at least one gift at least one There are various gifts various kinds of ways that the gifts function Various uses is of the gifts in church services or regular daily life But every person has a gift every one of you if you're a believer in Christ has a gift now the question is Do you know what your gift is? Do you know what you're gifted now? There are people who say oh, I'm a teacher. How do you know that? Because I like to talk But when you talk to people listen and do their lives change see so there are things that that help you to understand That as you go through scripture, how do you know your gift? Listen when I first got saved? I I'm brand-new what do I know about spiritual gifts and all of that and I was like two and a half years old in Christ And we were having a fellowship at my at my parents house. I had been in the military. I got out of the army It was during the summer of 1973. So at that time I was probably 20 22 years old or so right in that area 22 and and We invited a group of young adults to come to to my parents home and a young man was there and He and I were speaking in the kitchen and My dad happened to be standing next to me as I was speaking to this young man again I'm 22 less than 23 and He said something and out of just conversation. It was all only Conversation he had said something scripture about the scripture and I said well, that's really not what the Bible says now That wasn't done in an arrogant way or a self-righteous way. It was a conversation See when I got saved I started reading the Bible. I was told to do that and Then as I read the Bible, I I started learning things I actually was buying books that that would help me to understand and all of that I began to speak to to people about Christ and it was just an interest I had on my own I figured if you get saved you ought to know what you believe and it's just that simple It makes sense to me and that's what I was doing And so as I was sharing with this fellow I he had said such and so and I said well, you know the Bible doesn't really say that Because this scripture says this and I quoted a couple scriptures and so he says oh, thanks He said I never knew that and I said yeah, isn't cool. You know it gives a conversation He walks away and my father says to me. I'll never forget this my dad looks at me and my dad says I didn't know you could do that and I said do what? He says I didn't know you could explain the scriptures So people could understand I said really I Didn't either because it wasn't something I was thinking about and so That's when I began to be aware that perhaps I have a gift to teach perhaps Now my mom got sick of my gift of teaching. I have to be honest with you because She she she would ask me questions and and I would give these long answers sound familiar And she say David Can't you give me just a simple answer and I'd say mama the question you're asking isn't simple There's I said the the word of God is is is simple in the sense of being able to understand it easily even a child can But it's not simplistic and what you're asking me to be a simplistic to gel it down to something that really is just superficial I can't do that That's when I began to discover that Maybe Teaching is something I can do. What have you learned about yourself? What is it that you like to do? There's gifts of administration people say man You just how you all the detail detail detail just do it. You may have the gift of administration You may be a person who's just generous you see somebody with the need and and and you're there you have the gift of helps See so read Romans 12 read 1st Peter 4 read 1st Corinthians 12 and 14 Read these passages First and these various places where the spiritual gifts are spoken of and I'm telling you as you seek the Lord in this You'll discover what it is you should do because he's gifted you to do that He's giving you the ability to do that and that's what gives you joy.  What do you mean? He says, you know because ministers never retire and this truth to that my pastor Chuck told me this one time Chuck Smith He said I asked him what do you retire? He says when you get tired of talking about Jesus, which means you don't you never do and so What is your gift because we're to be busy and that's what Jesus is speaking about here by the way That's what he's referring to. He said he gave to his servants authority to his servants and to each one his work commanded the doorkeeper to watch So each of us has been given this ability notice in verse 34. He commanded the doorkeeper to watch The doorkeeper cares for those who are entering in or leaving the house Doorkeepers had responsibility they guarded the door to make sure no enemy would creep in in John 10 verses 1 through 3 We see an example Similar example where it says most assuredly I say to you he who does not enter the sheepfold by the door But climbs up some other way the same is a thief and a robber But he who enters by the door is the shepherd of the sheep To him the doorkeeper opens and the sheep hears voice And he calls his own sheep by name and leads them out Now in a sense believers are doorkeepers But especially this could refer to the leaders of the congregation in Ephesians 4 11 through 13 he himself gave some to be apostles some prophets some evangelists some pastors and teachers For the equipping of the saints for the work of ministry for the edifying of the body of Christ Till we all come to the unity of the faith and of the knowledge of the Son of God To a perfect or a mature man to the measure of the stature of the fullness of Christ So we've been given Responsibilities apostle-prophet evangelists in our day pastor teacher is given the Responsibility to guard the door to give the word of God properly in first Thessalonians 2 verse 4 as we've been approved by God to be entrusted with the gospel Even so we speak not as pleasing men, but God who tests our hearts the door keepers Doorkeepers responsibility is to please God to protect the sheep to give those things that that the sheep should hear in order that they're Protected and they can grow and then they're not duped by the deceivers who come in and so he's using an illustration of the one who is who is there appointed to a task and he's watching Now this is going to be especially true during the tribulation when deception is rampant they have to be on the alert They need to be ready to welcome the master home and therefore verse 35. He says watch Watch therefore for you do not know when the master of the house is coming in the evening at midnight At the groin of the rooster or in the morning. Let's come in suddenly. He finds you sleeping What I say to you I say to all Watch He can come at any time Where to be ready and Where to be awake in? Luke 21 34 through 36 take heed to yourselves Lest your hearts be weighed down with corousing drunkenness Cares of this life and that day come on you unexpectedly For it will come as a snare on all those who dwell on the face of the whole earth Watch therefore and pray always that you may be counted worthy to escape all these things That will come to pass and to stand before the Son of man all the way back in 2004 Some of you might remember you're old enough to remember the the tsunami that hit and destroyed much in the east it hit the the land of Thailand and Devastated I had the opportunity of going to Phuket Thailand Right after that had taken place our fellowship Without us receiving an offering You know bypassing a bucket and I still remember saying to the church at that time all the way back in in 04 I said if you want to be of help to minister to these people who have been devastated We went I have pictures of the the the water that rose up over the over eight to ten feet I mean it was devastating I said if you want to be of any help and all then then I'm not receiving an offering but but Anything you designate we will give to them and and about a hundred and almost a hundred and seventy thousand dollars Spontaneously came in from the congregation at that time to minister to those in that kind of need and and so we helped an awful lot This fellowship helped an awful lot Those who had been devastated in this terrible terrible Tsunami and I remember watching a video of a man who was on a on a rooftop You could see the the wave as he's on the rooftop and he's yelling Because what has happened is he is at a vantage point he's up here he can look down and We're there with him if you will in the video We can see the wave that is building and some of you know this already, but a tsunami what happens is the water recedes It comes off of the beach area and it recedes it can go a quarter mile or further out than it normally is and so From his vantage point. He sees this wave that's building now I read an article that says that that that on the open ocean This is hard to believe but that the wave can actually outrun an airplane I mean it's coming in a way that's so devastating None of us have an idea of what that is but what it does is it the wave the water as it's receding all of the Debris and you know the trees and various things that are there under the water It's all being sucked in by this Enormous wave that is growing and so if it hits you it's like you go into you know a blender You're instantly destroyed your body is torn up.  It's coming It's going to destroy you and there's a man with a basket and he's walking picking up the fish that have been left there Because when the water receded there were fish that remained behind This is a guy who sells fish at a fish market. He's saying what a blessing what a benefit I have all of these fish that I can now sell He's looking at the fish and not the wave and then you have the man up there screaming Run for your life as the wave hits him and he's obliterated for some fish a basket of fish As a pastor I feel that way myself. I have a vantage point through the word of God. It's coming and There are people just picking up the fish People are leaving and they're running to get away from the destruction But this man is there picking up the fish and Jesus says watch He don't know when it's coming But it is as sure as God's word It is coming This will happen But many many pastors myself included can often feel like that man on that roof seeing something and nobody will listen There's a fable a story. It's not in the Bible. It's just an illustration That tells of three Apprentice devils who were coming to earth to finish their apprenticeship and They're talking to Satan the chief of devils About their plans to tempt and to ruin men The first said I will tell them there's no God Satan said that will not delude many for they know that there's a God The second said I will tell them there's no hell and Satan answered you will deceive no one that way Men know even now that there's a hell for sin the third said I Will tell men there's no hurry Ghosts at Satan you will ruin men by the thousands Because the most dangerous of all delusions is that there is plenty of time First Peter 4 7 the end of all things is at hand Therefore be serious and watchful in your prayers be serious and watchful in your prayers Behold I stand at the door and knock If any man hear my voice and open the door I will come into him and sup with him and he with me Very often we use that scripture as an appeal for people to come to faith in Christ But the context is dictating that the Lord Jesus Christ is telling the lukewarm church You're not ready. I'm coming suddenly And you're going to discover That you weren't prepared I just say to us as a church and those who are listening Watch Be ready Be prepared He comes in a moment that you don't expect And the rapture is coming soon May may we be prepared to go with the Lord Jesus Christ Jesus is warning believers to remain faithful And expectant Lord I ask that you would work with


Luke, you retire 10 batters tonight. We saw a bit of everything. What did you feel was working for you within your pitches? Yeah, I think there was a lot of discussion with me and Trevi of a balanced attack, just trying to get everything working, trust to find moments to use the curveball, which is something I don't typically use a lot, and really try to not rely too much on the fastball but have moments where the change up and the cutter can be good spots. So there was great communication on that on the front end and through the game. And I feel like it was just a good overall game plan and it reaped the benefits of it. You spoke earlier in the spring about your happiness, about where your fastball velocity is at. How would you rate it tonight? Yeah, it was great to be able to hold it throughout. I think our scoreboard out there is one down. So that was never, I have to remind myself, OK, maybe it's a little bit better than that. But no, it's great to feel like it coming out well. And I think when you look at some swings from the other side, like they're kind of showing you where it's at, too. Some late swings, some foul balls, not necessarily getting to the pole side on some stuff. And it just shows that it's really coming out well. And I think that's just what we want as pitchers, especially with a foreseamer, and setting up other pitches to help complement them. Yeah, how does it complement a pitch like the cutter, a pitch that you continue to refine during the spring? Yeah, so they just have very similar spinning profiles. Obviously, one's going to cut and go a little bit to the left. But it's just really good to kind of tunnel those off of each other and have something that just darts off the barrel, away from the barrel, excuse me. So getting a ground ball, getting some weak contact, maybe backdooring something where it feels like it's going to come off, and it sneaks back. So those are just little, quote, unquote, sneak attacks off the fast spot to help complement that. Speaking of sneak attacks, you had a pick-off attempt in the first. You had a pick-off at first in the second, and the guys in the booth were wondering, were those pick-off attempts something that happened naturally in the flow of the game, or was it something that you work on during a spring start? Yeah, so the first one was something that we called for, was something that I was, I'm always trying to be aware. You got the clock going, and you're trying to manage your emotions in the next pitch, and then you got the guy out there. So it can be a lot, but I think being as calm and having that game plan, I was really trying to set them up with looks and different things that we do in order to try to keep them from not stealing. And it was just a great call to try to mix in, kind of slipped and threw something high. I feel like if it was on the money, we got them there. But the other one was just strictly, the first base was just strictly on me. It was just something that I think it was a pitch or two in, but I saw that he had a little bit of a jump going. And the second time, it was almost reactionary just to pick right when I saw it. And I was, there's a movie limitless for things kind of slow down, and in the moment, I felt like I turned and I saw where he was, and it was just a matter of trying to throw it up the line a little bit. And Rizzo Platinum, winner, by the way, I figured I was in good company there, but threw one and he scooped it, but it was just about getting up the line so the tag comes right into the runner. And I think that's most of the time where we're gonna get a pick off. So it was just decent execution with a little bit of help from our Platinum winner. And Aaron Boone told us that this was the best he's seen from you this spring. When you hear that in the midst of a competition for the fifth starters role, how do you react? Well, it's very kind of him. It's always goody-good to feel like your manager feels like you're in a good spot because that's where I feel confidently. I'm getting great feedback and good comments, and we're just always trying to build towards something. We're just always trying to continue to stay on our game, and they don't typically say comments like that all the time, so when they do, you don't necessarily pat yourself in the back, but you just feel grounded and strong in your foundation, and it's just nice to hear. I mean, we're human beings, and nice words go a long way. So it feels good, just ready to go, and whatever happens happens, but just happy to be a part of the team. Luke, thanks for the time. I appreciate you. You got it, thank you.


So at this point, you know, people who are really involved in these questions about reality, being, change in Athens and you know, pretty much most of ancient Greece, they're getting more than a little discouraged. Because so far, you know, from Baileys on, Baileys, Annexmen or Annexmenes, Heraclitus, Pythagoras, and Pettiglis, Annexagoras, Lucipus, the Democritus, there's just not a whole lot of agreement going on. They all disagree with each other. People are really seriously beginning to wonder whether these questions can be answered. People are beginning to wonder whether there is an answer to this question. Why make the distinction between appearance and reality to begin with? Well, along come a group of people called the Sophists. Now, the Sophists got their name because amongst one of the other things that they did is they trained people to argue any position whatsoever, for any conclusion whatsoever. You can kind of think of it as, you know, training somebody to persuade anybody to believe anything that you want. And those arguments were called Sophistry, hence the Sophists. So the Sophists, one thing to remember is that they are not Athenians. The Athenians, you know, had their own real consider views about what was real and how to argue for the truth. They had their own beliefs, especially in moral customs. They had a very elaborate set of moral customs, moral truths. And the Sophists, well, they were not Athenians. So basically they were foreigners and they came into Athens and compared their ideas with the Athenians. On top of that, the Sophists were really knowledgeable in other cultures and what they thought was more, what they thought was real. It doesn't take long, you know, if you're doing like a comparison in mythology across cultures to find that there's a lot of disagreement across cultures. So the Sophists were, you know, really kind of convinced that, you know, in various ways shape or form that there wasn't any kind of absolute truth.  And, you know, we make the same claim today. We say something like, well, there's, especially about morality. We say, well, since there's all this difference in morality across cultures, there just must be no absolute moral truth. Well, we're going to take a look at these arguments from Protagoras, Gorgias, and Thrasymachus. If you think there aren't any nice natural areas around Texas or around San Antonio, you're not looking hard enough. The first Sophists we're going to look at is Protagoras. And Protagoras argues is that everybody is right. Everybody has, every belief that they have is true. And again, this kind of follows from, you know, it's associated with this idea that there is no absolute truth. In fact, he's going to argue that since everybody's right, there is no absolute truth. The way that he does this is he relies heavily on the idea that our knowledge, all of our knowledge comes from perception. So I'm looking around me now, and I see trees, I see water, I feel the air, it's warm, it's humid, and these are my perceptions. And that's how I come to knowledge about the world. So Protagoras' argument begins with the claim, maybe the observation, that all of our knowledge begins with perception. So I see brown trees, I see green needles, I feel rigid bark, I hear water. If I were to dip my hand in the water, it would feel cool. I see this from a particular angle. So that much seems pretty right. Protagoras goes on, he says, look, people have different perceptions. I'm looking at this tree from a particular angle, but somebody else looking at it would have to be at a different position than I am. Well that different position means there's a different perception. You're seeing the tree behind me from a particular angle. I'm seeing it from a very different angle. So our perceptions of this tree, of all trees, are very different. In fact, our perceptions vary from person to person. There's a lot of variation, and nobody has the same perceptions as anybody else. I mean, there's lots of, you know, contemporary evidence that shows this is true. You know, for instance, I'm slightly colorblind, and I have color deficiency. I can't see as many colors as you do. So my perceptions of what's going on around me are going to be different than yours simply because you see more colors. You know, even perceptions of what's true if they are perceptions at all. Our perceptions of what is true varies from person to person. Nobody has an identical set of beliefs about the world around them. So since our knowledge begins with perception and this perception varies from person to person, we don't have any test to see who's right. We don't have any way to determine whose perception is the right one. If there's no way to determine whose perception is the right one, it really doesn't look like a way to distinguish between appearance and reality. We just have our perceptions. I mean, there's no reality to match up to them. Well, if there's no way to test who's right, well, Protagoras says, well, that means there's no absolute truth. Since there's no way to determine who's right, there is no right. There's no absolute truth. There's no absolute truth. There's just what you believe. There's what you get from your perceptions and that's all you really need. That's all you need to know. So this is an extreme claim. Everybody is right. You might wonder if you agree with that. Gorgias is next. Gorgias is an interesting character. Gorgias was an extreme skeptic. Now, skeptic denies that we have knowledge or sometimes that there's truth about some particular question or field or discipline.  Gorgias was a skeptic to an extreme condition. He thought that there wasn't any truth whatsoever to be known at all. Where Patagoras thought that everybody was right. Gorgias pretty much thought that everybody was wrong in a way. You can believe what you want to believe, but there's no truth to what you believe and you don't know it at all. He does this by arguing three things. He argues that nothing exists. Even if something existed, then it would be incomprehensible. And even if it were comprehensible, you wouldn't be able to communicate it. Pretty extreme position. If you're saying nothing exists, then yeah, that's hard to believe. Well, how's Patagoras going to do that? Well, remember he's arguing that nothing exists. Even if it did exist, it's incomprehensible. Even if it were comprehensible, you wouldn't be able to communicate it. Well, let's start with how he does this. The way he does this is he does kind of a reductio. So to do a reductio, remember, you assume the proposition that you want to show is false, you assume that it's true. So he starts by assuming something exists. You agree with this assumption, you think at least you exist. Well, we also think that if something exists, then we can comprehend it. So I'm looking around me and I see trees. There's this tree right here. This tree exists and I can comprehend it. I know things about the tree. It's tall, it's rigid. It has its own metabolism. It uses the water. So I know things about the tree. How do I know things about the tree? Well, we've got a protagonist in the background here. Gorgias says, look, if we know something, we know it only through perception. We know it only through perception. And it seems pretty right. Physical sciences go about their business by using observation. My mind does not have access to the tree. I can't use my mind, send it out to touch the tree and then to understand it. No, I have to use perceptions. I have to use sight, sound, smell, taste, touch. Well, guess what? If you're using perception to know the thing, what you know are your perceptions. You don't know the thing itself. And it seems like he's right here. I have access to my perceptions. My mind has access to my perceptions. My mind does not have access to this tree. The tree is something distinct from my mind. If I were to be able to know the tree without using perceptions, I could just close my eyes and use my mind to contact the tree. That doesn't happen. The same thing with the water and the sky. The bugs that I hear right now, they're making that buzzing sound. My mind can't access those bugs. I don't even know where they are. I can only hear the sound and I know what's happening around that away. So if what I know are the perceptions and not the thing, the one I'm comprehending are the perceptions. I'm not comprehending the thing. My mind doesn't have access to the tree. That's not what I'm comprehending. What my mind has access to are the perceptions. What happens now? I started with the presumption that if something exists, then I could comprehend it. So I conclude that I can comprehend it. But now it looks like, by the way, I comprehend things. I don't actually comprehend these things. I comprehend my perceptions without the things themselves. With that in place, I've drawn a contradiction. So it's false that something exists. It's also false that even if it did exist, that I comprehend it. Well, I couldn't comprehend it because I know the presumption is not the thing. So just with that one single stroke, with dealing with existence and comprehension and perceptions, Gorgias has wiped out existence. And even if it existed, we couldn't comprehend it. Well, if I don't exist, I don't know what I'm doing here. That's a bit of an uneven path. Lots of sticks and roots in the way. Some mud, too. A lot of shade coming off of the side of the hill. What I'm doing right now is I'm trying to communicate the things that I see around me. Now, Gorgias thinks that I can't actually do this. That I'm mistaken.  I had to use words. Words, whether they're spoken or written, are symbols. The words uneven, root, mud, tree, shade, sun. The words are not the things themselves. When I say the word sun, the sun doesn't come out of my mouth. It's a representation of the thing. It's not the thing itself. Well, Gorgias has already argued that nothing exists. And even if it did exist, we couldn't comprehend it. Now he's going to argue that even if we could comprehend it, we can't communicate it. And to do this again, he uses a reductio. First he assumes, yeah, if you comprehend something, then you can't communicate it. But what's involved in that communication? Well, if you're communicating, then you're using symbols.  Rough, uneven, root, mud, sun. But these symbols are what I have. And everybody has their own set of symbols. Now by that, he doesn't mean they're all speaking different languages. Sometimes that happens, but not always. What he means by that is, you know, I'm using the word sun, but that doesn't mean that you're using the word sun in the same way. Think back to Protagoras, where Protagoras is saying about perceptions. We all have our different perceptions. We all perceive things exactly the same way. So for instance, the sun is not my friend. There's a reason why I'm usually wearing a hat. The sun burns my skin. It hurts my eyes. It causes actually some other health problems. So I can't stay out the sun for very long. As a matter of fact, the sun is not a good thing, necessarily a good thing to me. It has a lot of problems. A lot of people are different when they think about the sun. They like the sun. They like laying out on the sun. They enjoy being out in extended periods of sunlight. I can't do that. Undoubtedly, their experiences, their perceptions of the sun are different than mine. Therefore, when they use the word sun, they mean something different than I do.  Other people mean wonderful glowing aura of light that brings joy to their lives. So what this means is that everybody has their own symbols. They already have their own meanings for the symbols. Well, if we're using different meanings for the words, for the symbols, then we're not actually communicating. I might use the word sun, and you would use the word sun, but we have different meanings there. So to sum up, this is Gorgias' point with this last argument, is even if we could comprehend it, because we use different symbols, we are not communicating. So what does Gorgias argued here? Well, he's argued that nothing exists. Even if it did exist, we couldn't comprehend it. Even if it could comprehend it, we couldn't communicate it. And from all of this, he concludes, therefore, there's no truth. I say the sun is shining. There's no truth to that. I say the water is flowing. There's no truth to that. I can say the sun is hidden. There's no truth to that either. I can say that the water is completely still. There's no truth to that. Gorgias is an extremely, extreme position here. It's a very extreme skepticism. Nothing, absolutely nothing is true. I don't know about you, but I feel a little sad. The last soap we're going to look at is Thersemicus. Thersemicus argues for a kind of moral relativism. Moral relativism will say, more claims are true or false depending upon some condition. For instance, culture relativism says that moral claims are true depending upon what the custom says, what the culture says. So, for instance, it's contrary to our custom to swim in this river without a swimsuit. If you did that, you'd get arrested and people would scorn you. However, that custom is not always the case depending upon where you go. Other cultures not only think it's perfectly acceptable to swim in rivers in the nude, but sometimes it's expected. Well, Thersemicus offers a kind of moral custom, but he tags on something to it. So, he starts off with the observation that moral customs vary from culture to culture. And that's true. It doesn't take very long to figure that out. Especially if you have roots in more than one culture, you know this is true. In addition to that, Thersemicus adds on the observation, or at least the claim, that moral customs, that there's something that all moral customs have in common. And what they have in common is that they benefit those in power. And even more so, the moral customers are there to keep those in power in power. So, from this, he draws a conclusion. Since there's this great variety of moral customs and moral customs benefit those in power, what makes something moral is if the powerful say it's moral. Yeah. So, this is a moral relativism on the condition of power. You want to know what's moral? Figure out what the most powerful person says is moral. Tough pill to swallow. Thersemicus continues with an observation about what about justice. And justice roughly means that you give to people what's due to them. So, if I agreed to, you know, work for an employer to do a certain kind of labor for a wage, then at the completion of that labor, the employer should give me the wage. That's just. It would be unjust for the employer to withhold the wage. And similarly, it would be unjust for me to take the wage but then not do the labor. You give to everybody what's due. Well, Thersemicus makes an observation on this. He says, look, if justice is in place, that means that that limits what those in power can do. As a matter of fact, those in power take advantage of those that don't have power. It's called corruption. It really ticks us off. It happens all the time. But Thersemicus says, yeah, it happens all the time. But if justice were in place, that would limit what those in power can do. Now, since morality is what the powerful say it is and since justice limits what the powerful could do, well, then justice is immoral. Justice is immoral. Another consequence is that there's no absolute truth, no absolute moral truth. Because what's moral just depends on what the powerful say it is. So this is another extreme position. There's a lot of people who have some pretty strong tendencies towards cultural relativism. But to say that what the powerful do just is what's moral. That's tough.


Thank you. Thanks for the introduction. Thank you for showing up this morning and So in this talk, I'm going to talk about encryption and authentication with information theoretic security So the typical examples are the one-time pad for encryption and universal hashing for authentication Now the obvious well-known downside of these kinds of scheme is that the key cannot be reused Right in a one-time pad you can only use your key once well That's why it's called the one-time pad and sort of in general Can only use the key a bounded number of times for these kinds of information theoretic secure schemes and the reason is quite obvious least intuitively a Attacker if can learn information on the key just by observing the cipher text or the authentication tag See if you reuse the key just by observing the communication the attacker if you'll learn more and more information on the key and will eventually know the key and What's even worse than that such a passive eavesdropping attack remains undetected, right? There's no way to detect whether If dropping took place or not so this means even if I'm not under attack And so my key would still be perfectly fine to use for a next round I cannot use it because I don't know So I have to assume the worst have to throw it away take a new key So that's sort of where now the idea of quantum kicks in or the idea of Using a scheme with a quantum cipher text or quantum authentication tag instead because there we can make use of the fundamental Property of quantum mechanics that any eavesdropping will disturb the state Right, so this is hope for a scheme that sort of encodes the cipher text or the tag Into a quantum state and that we can then Check upon arrival if the state is still in good form and if he did then conclude that no eavesdropping took place And therefore it's safe to reuse the key right? I mean if he had such a scheme this would allow us for Unbounded safe reuse of the key as long as we're not under attack now as soon as we are under attack Then if may have learned the information on the key then well There's nothing that we can do then some key refreshing has to take place But the goal is to be able to reuse the key as long as we're not under attack So if that's the general idea now this idea is not new it's only adult It actually goes back to an old paper by Bennett browser and Breitbart from 1982 So no that's even before quantum key distribution was was a proposed So in their paper they proposed a simple scheme for this kind of encryption with key recycling and gave very Hand-wavy arguments for for its security now They submitted the paper, but it got rejected and then they had the idea of doing quantum key Distribution instead and the original idea of encryption with key recycling was abandoned until in 2005 Dumbgaard, Peterson and Sunwell picked up this idea again and proposed a new scheme for for this kind of encryption with key recycling But now together with a rigorous security proof However, their scheme was More complicated than the original scheme in particular the quantum encoding was more Sophisticated and your in the original scheme to the point that in order to actually perform this quantum encoding You need quantum computing capabilities meaning for honest users to execute the scheme. Well, they need to have a quantum computer So our result is a new scheme a new simple scheme very much in the spirit of the original scheme by Bennett at all In particular, it's based on what we nowadays call BB 84 qubits or simple quantum states that we can't deal with With current technology in particular no quantum computing is involved and of course our scheme comes along with a rigorous security proof as well I will also want to briefly mention a related line of research on encryption and authentication of quantum messages Where the data that you want to protect is a quantum state So Christopher is going to talk about this kind of Of work in the next presentation here I just want to mention that some of these schemes also offer some key recycling features But in all of these schemes, we also have that the honest users need quantum computing capabilities to run the schemes Even if you restrict the message is to be classical in these schemes Okay, so before I go into more details about our result I want to say a few words about the Distinction between encryption with key recycling and quantum key distribution because well, we also gonna need quantum Communication so we're in a setting where we can also run quantum key distribution Then may wonder why do we even care about Reusing keys well if we cannot reuse the key you could just run quantum key distribution instead to produce a fresh key Right now, I mean that's true So from a high level these two things achieve pretty much the same thing But there are some subtle technical differences. So for instance one Advantage of encryption with key recycling is that it's essentially Non-interactive sort of the only interaction necessary sort of a one-bit feedback where the receiver tells the sender Whether the key is still safe or not whether it can be reused in the next round of Interaction that that feedback can be provided of line whereas in quantum key distribution That's inherently Interactive during the execution of the scheme but then on the other hand because you have this interaction quantum key distribution There you can adaptively adjust to the noise that you have in the quantum communication, which is something you can Inherently not doing a non-interactive encryption scheme But well independent of these technical differences my our main motivation was sort of Intellectual interest because encryption with key recycling was one of the very first suggestions of using quantum mechanics In the context of crypto more than 30 years later. It was me still no really satisfactory solution Okay, so in our basic scheme we're just gonna focus on Authentication right protecting the message from being modified and so when we don't care yet about if learning what the message is Building encryption on top is then not so hard anymore. And I'll say a few words about that later on So as you'll see our scheme is extremely simple And the key the shared key consists of two parts, which we call theta and K And now to authenticate the message M if not if sorry Alice does the following She chooses a uniformly random bit string X and Encodes it into cubits using theta the first part of the key SS basis So this is just a standard bb84 encoding of classical bits into cubits Which you see in essentially every talk on on quantum crypto and Then she sends these cubits to Bob along with an authentication tag T on the message Concatenated with this additional randomness X here so Mac here is just a Standard classical one-time secure information theoretic Mac And I mean they're using the key the second part of of their shared key SS key of this Mac here But for concreteness also because I'm actually going to use certain special properties Let's think of that particular Instanciation of such a Mac where the key consists of a random matrix a and the random vector b and the tag is Computed by means of this linear function is sort of a canonical choice of such a Mac Okay Bob well Bob he does pretty much the obvious thing now. He also knows theta He knows the basis that was used when code the bits of X into cubits So by performing the correct measurement, he's able to recover X and of course once he has X And well the message is signed sent along here as well Then he can check the correctness of the tag here That's what he does when he accepts if the check works out and the rejects if it doesn't work out Well, that's that's a scheme extremely simple So informally these are the security claims that I make about the scheme So first of all the scheme offers Authentication security meaning that Bob is gonna detect any modification to the message and well That's pretty obvious That's just sort of the job of this Mac here So if this Mac here ensures that any modification in particular to the message here is gonna be Detected at least as long as a sort of this key is sort of good And it's certainly good sort of at the beginning of time so to speak Now the second sort of more interesting claim is that if Bob accepts And then the key can be safely reused for Authenticating a second message a third message and so on and so forth So even typically this kind of Mac We can only use once with a given key here sort of the statement is if Bob accepts Then they can actually reuse the same key here in the next round for for this Authentication for computing this authentication take here and Third point if Bob rejects well, then some if stopping may have taken place You may have learned some information on the key Then some key refreshing has to take place and the claims and is it's good enough to refresh theta But K can still be reused Okay The intuition behind this key reusing properties is the following Now it's easy to see that if if gets to see well more and more Authentication tags for known messages under a fixed key Then she accumulates more and more linear information on the key will eventually be able to solve it Right. I mean that's just sort of the typical argument why you cannot reuse the key For for such a Mac here usually but now here here the difference is that the Authenticated message is partly unknown because we have this additional randomness X here in the message and sort of Intuitively because if does not know theta X is sort of hidden at least to some extent behind these qubits for Eve So intuitively We expect that there's some uncertainty in the message X and therefore there is hope that the Authentication tag does actually not leak information on the key in particular if we assume that Well, this this computation here has some extractor like properties And this is actually sort of a function that you would expect to have some extractor like properties or actually know that it has some extractor like properties and I mean that's sort of what we're proving in the end that this is the case Okay, I think it's going to be insightful before I go into more formal statements to consider a Particular attack and I have your attack in quotation marks because it's not an attack that breaks the scheme Well, our scheme is well proven It's a cure just something that you can do and I think it's insightful to see what what happens under this kind of attack So here again, I have to scheme as I had it on the previous slide except that I'm spelling out here the Individual qubits that Ellie sends to Bob Now the attack is as follows if simply measures the first qubit in the computational basis So kind of pretending theta one was one and then she leans back Okay, so let's see. What's the effect of that? Well, if the first qubit had been prepared in the computational basis, so theta one was zero then by measuring it in the Computational basis if he's not disturbing the qubit Meaning that Bob will receive the correct state so everything is gonna look okay to him and he's gonna accept However, if the first qubit had been prepared in the Hadamard basis by Ellie's so theta one was actually one Then by measuring it in the computational basis if he's gonna disturb this qubit to the point that Bob will recover Incorrect X1 with probability one half in this case is gonna reject because X is authenticated along with the message So now this means from Eve's perspective If Bob rejects she knows theta one must have been one, right? So she's learned one bit of information on on the key Now the bad news for her is that now because Bob has rejected Well by sort of definition or by the way the scheme works They now have to refresh or they refresh theta So the one bit of information she just got on the theta becomes useless to her because Bob rejected So they throw away seat and replace it by a fresh choice anyway however, if Bob accepts Then well see the one can still be both zero or one, but it's somewhat biased It's sort of more likely to be zero which can quite easily be seen So also here if has learned some information on on the key It's not sort of a constant fraction of a bit of information if you wish, but now this key is gonna be reused Now intuitively this should not worry us or this does not have to worry us Because if Eve tries to gain more and more information on theta by repeating attack pretty soon She's gonna be detected pretty soon Bob is gonna reject because every time she launches The attack Bob is gonna reject with probability one quarter and as soon as he rejects Well, they're throwing away theta replace it by a fresh choice So all the information that if gained on theta becomes useless to her Okay, so why did I discuss this attack? I think this attack shows nicely what we can or more cannot expect to be able to prove formally So it shows that it's not possible to prove a statement of the form if Bob accepts Then the key remains close to uniformly random because we've just seen an attack That sort of contradicts this that shows that this is not possible and sort of the inside here Is that it may be not be necessary for the key to be uniformly random to do its job in this Authentication scheme that it might be good enough to have high enough uncertainty indeed. That's what what what we show I think it's sort of this Inside that explains at least to some extent why in previous approaches sort of people fail Because in previous approaches people try to prove exactly the statement that after the If Bob accepts then the key stays close to uniformly random But if you have a scheme that works QB twice then this kind of attack always works and sort of contradicts this statement Okay, so the formal statement that we prove slightly informally stated here is if before the execution We have the following sort of security property on the key First the guessing probability on theta from East perspective should be small and K The second part of the key should be close to uniformly random if this holds before the execution of thinking of the scheme Then it's also gonna hold after the execution of the of the scheme where I take it as understood here that After the execution of the scheme I'm gonna look at theta prime, which is the possibly Refreshed version of theta so it's equal to theta if Bob accepted and it freshly chosen otherwise So we have sort of this invariant that is kept alive over Over all execution in particular It's in short that K the key for the max stays close to uniformly random and does its job as a key for a for the Mac so this means for instance We start off with a uniformly random key Then we can keep on reusing it as long as Bob accepts and we can still keep on reusing it if Bob rejects If theta part is refreshed Okay, I'm gonna walk you through the easy part of the proof For that let's first note that if view after the execution of the scheme consists of her old view Before the execution of the scheme the authentication tag that you observed Whatever quantum information she keeps on the original qubits that Alice sent and Bob's decision To accept or reject so then we can spell out the guessing probability after the execution of the scheme Like this and then we can decompose this into the case where Bob rejects and the case where Bob accepts Then we observe that if Bob rejects then theta prime is freshly chosen if he accepts then theta prime equals theta But well for a freshly chosen theta prime the guessing probability is just one over the number of possible choices for a theta And here we're using the property of the guessing probability that the guessing probability cannot in if you condition on an event The guessing probability cannot increase by more than one over the probability of this event Which is that sort of cancelled out with this probability here So we end up with this term here and then we note that by assumption the key the Authentication key is close to uniformly random So a and b are close to uniformly random which means the t here the tag is close to uniformly random independent of theta so that doesn't contribute to the guessing probability here and Q's information that if has kept on the original qubits Well doesn't provide her more information than the original qubits and here we can observe that x is uniformly random Joe's and and therefore these qubits are independent of theta at first glance They look dependent on theta because we have theta in the exponent but because x is uniformly random It's a little bit like a one-time path of that removes all dependency from these qubits From theta and so this also doesn't contribute and we end up with the guessing probability before the execution of the scheme And so if that was small then the guessing probability after the execution is small as well Okay, so that was the easy part the other part proving that the other part of the key stays close to uniformly random is way more Involved and we're building up on well techniques from a previous paper Okay, so extending this basic scheme to an encryption scheme with key recycling is quite Easy we just use the randomness extractor with a seed that is part of the shared key to extract the randomness from x and use That randomness to a to one-time path encrypt the message You can also Enhance the scheme to take care of noise in the quantum communication here Doing the air correction is straightforward way Brings us into trouble, but there's a nice air correction without leaking partial information techniques by Afghani and Adam that that come to the rescue I want to say sort of just very quickly. What's the trouble with with air correction? Sort of the obvious solution for doing error correction is just to send the syndrome of x along so that if Bob Recovers a noisy version of x he can recover the right x with the help of this syndrome But the problem is if you then go through this this Analysis that I just did a couple of slides ago Then we get this expression where we now additionally condition on the syndrome here And now the argument that because x is uniformly random This does not depend on see that does not hold anymore because given the syndrome x obviously is not uniformly random anymore Now if one sort of meditates over this expression and understands what it captures It's quite clear that it should still be small, but we have no clue how to prove it Okay, so in conclusion what we did is we well considered one of the very first ideas For quantum crypto one of the very first ideas of using techniques from quantum mechanics to circumvent the classical impossibility result in Crypto an idea that was suggested more than 30 years ago even before quantum key distribution was invented and we give the first provably secure solution that doesn't require any quantum computing capabilities and An intriguing open problem is to do this error correction in a better way if you could do it in the Straightforward in the obvious way this would give us not only a nicer more natural skin But what also allows to tolerate more noise because these techniques by if gaining and that and the only work for a relatively small amount of noise and another interesting question or line of Direction would be from practical perspective to minimize the amount of quantum communication necessary to make the scheme really competitive with a quantum key distribution and That's concludes my talk. Thank you for your attention Any quick question? Do you have an intuition why these attacks to quantum money like visitor quantum money doesn't work here because it's the same kind of states that you like they had there I don't know what what these attacks or that you're talking about Maybe you can talk a flag. Yes. Mm-hmm. Sure