be talking about what is good test coverage and why does it matter? So I'm gonna start with why this talk. Where I came from before a couple years ago, I did a lot of Java development and a lot of PHP development and I'd never written a test in my life. I think maybe once I had a college assignment and I wrote assert true equals true and thought this is dumb. But then I joined Pivotal Labs. Pivotal Labs is a you know big on test-driven development and testing and I kind of got immersed into this world of testing code. And I found it really interesting. I love testing. I love TDD. I love to argue about it and talk about it and try to convince people it's a good idea. So I was surprised a few months ago when I read a blog post with this title. TDD is dead long-lived testing. I'm sure many of you read this blog post. DHH wrote it. He gave a very lovely talk at RailsConf around it. And it interested me. I mean the blog post to be honest is a little bit of a mess. There's a lot of different points mixed in there about TDD and about test practices that don't necessarily all fall under this title. But there is one quote that I pulled from that that really kind of started to pique my interest. And it was this one which I'll read. I test active record models directly, letting them hit the database and through the use of fixtures. Then layered on top is currently a set of controller tests. But I'd much rather replace those with even higher level system tests through Capybara or similar. Now you'll notice this really doesn't have a lot to do with TDD being dead or long-lived testing. But it is an interesting point. And before I go any further, I wouldn't be a good pivot if I didn't defend TDD for a quick moment. So here's why I like TDD. I think that a lot of times it helps you develop faster. It promotes good design practices, which is something I know DHH would disagree with me about. It promotes Yagney. It kind of keeps you focused on building exactly what you need and nothing more, nothing less. It helps promote the single responsibility principle if my testing is difficult to do because I have five things going on in a single object. Then it kind of helps me find those kinds of smells. And I think the best part for me is that it promotes testing to first-class status. So because I'm writing tests first, I'm kind of building up test coverage. But it does bring up a good question, which is, am I getting good test coverage from the test that I write when I do TDD? And we'll come back to that. So after that blog post got published, Uncle Bob had a great response, which I will also read out a good quote from. If you have a test suite that you trust so much that you are willing to deploy the system based solely on those tests passing. And if that test suite can be executed in seconds or minutes, then you can quickly and easily clean the code without fear. So it's kind of a run-on sentence, but let's distill it down to its two main points here. And I want to kind of form these as a question that you can think about. Does my test suite give me confidence to deploy the system? If my tests are passing, can I say ship it? And is my test suite solid enough? Is it fast, and is it reliable enough to allow me to refactor and change and modify and add to the code? So with that in mind, I'm going to start talking about test coverage. So let's talk about the traditional definition of test coverage. So there's a few different ways of measuring coverage.  And so there are different ways to measure that. So I'm going to give a quick introduction to that. So here's a piece of code that do I need groceries method. I'm a bachelor, so if my fridge or my pantry have food, I don't need groceries. So I say if both of them are empty, or if either of them are empty, actually sorry, if either of them are empty, I get groceries. Otherwise, I don't. So function coverage says, I write this test, I call do I need groceries, I pass some arguments, I assert. I have called the function, therefore function coverage has been met. Now we can get a little more specific. So here's another piece of code. I returned the numeric day of the week. And I have a flag that says, do I want today's date or not? And so statement coverage would say that I write this test, I call numeric day, I assert on the result. And I've covered every single statement inside of this block of code. But you'll notice that there's a huge problem with this. Which is that if I pass false to this method, it will blow up because I have an initialized date. But statement coverage has been met. So now we go back to the do I need groceries method. And we'll talk about branch coverage. So you're familiar with the method now. Here are my tests. So in one case, I say I pass empty and full, I get true. I pass full and full, and I get false. And so going back to the code, I've covered both branches of execution here. And so branch coverage has been met. Back to the same piece of code, condition coverage is another type of measure. And we go back to our tests and what condition coverage says is that both sides of my Boolean expression have evaluated to true and false. So in this case, I pass empty and full, and I pass full and empty. And I have satisfied condition coverage. But you'll notice I don't actually have a test that returns me false. So then we get further down and we get condition decision coverage. And that is kind of a combination of branch and condition coverage. And so now we have kind of probably what you would write if you were going to write tests for this, which is the empty full, the full empty and the full full case. And you can actually get deeper. There is a modified condition decision coverage, which says that every Boolean expression should affect the result on its own. And there's multiple decision coverage, which is basically sending in a truth table. You see those more in safety, critical applications like aviation. But we have some basic kind of understanding now of how our tools measure coverage. In Ruby, most of the coverage tools measure line coverage, also known as C0 coverage, which is more or less statement coverage. There's some differences there, but I'm not going to get into those. But let's talk about the downside of measuring coverage this way. First of all, not all tools are created equal. So as I just said, Ruby is lacking in getting kind of deeper into this condition decision coverage and these kind of more meaningful metrics. It only covers have I executed every line. Missing code. So here in this example, here in this example, I have a little block of code. I test this variable and I say if it's foo, I do in some action. If it's bar, I do some different action otherwise I raise. But what if there's an extremely valid case that my variable could have been assigned to Baz test coverage tools can only tell you how how covered the code you've written is, they can't tell you how much how covered the code you haven't written is. So this is also known as a fault of omission. And it's going to be missed by your coverage tool. Assertions. The first test there call do something and assert that it's true. Test coverage tools will tell you that you have the exact same amount of coverage from that first test as the second test where I don't have an assertion. So test coverage tools can't tell you that I've actually tested the behavior they can just say yep, lines of code were executed. Coverage goals are dangerous. So, you know, managers like to do this a lot. If I have something that gives me a number, then they'll say, well, let's set a target. So if I have this thing that can tell me percentage coverage, they'll say, well, we should meet 85% coverage. And what inevitably happens with a team that's told to have 85% coverage is that they get 85% coverage. And the reason for that is that, you know, no matter how well-intentioned the development team is, they will inevitably run into situations where they're having difficulty testing, and they might test the easy things that can get them up to those percentages, but, you know, they'll allow it to be a crutch to say that 85% coverage means I'm done.  You know, it just means that the metric is kind of driving the behavior of my team. So you have to be careful about setting goals with metrics like that. But now I've spent a lot of time dishing coverage metrics, but they actually are useful. They can help you find weaknesses in your test suite. So for example, if my tool tells me that this section of code here has 40% coverage, if the tool is smart enough to tell me that my coverage is bad, my coverage is probably bad, right? But the reverse isn't true. If my coverage tool tells me that I have 100% coverage, I could have a suite with no assertions in it. So I can't trust the good numbers, but I can use the numbers as a guide to tell me what are the problem areas, what are the areas that need more coverage. Metrics don't tell the whole story, though.  And this kind of goes back to what DHH was talking about that interested me, where he said, I want to see more capybara tests. I disagree with that, and I'm going to talk about why. So let's talk about types of tests. And for those of you who write tests, this is going to be a little bit boring, but bear with me here. So the most basic type of test is a unit test. So green block represents a unit of code, got some inputs, got some outputs, and I test just that block. If my block has dependencies, I mock them out, I do not allow that code to communicate externally. I just test the unit that is under test. So unit tests are fast to run. They're fast to debug, because I have a distinct unit of code that I'm testing, so I know if the test fails, exactly where to look. They cover a small logical subset of functionality, which is really what helps them be good for documentation. They're great. It's great to come in to modify an object and to have a nice unit test suite that allows me to see what is it doing and help me figure out where I need to add what I want to it. So then we step out a little bit, and we have integration tests. So this is that same code earlier, but I'm not going to stubborn mock my dependencies. So I'm testing the integration of my unit of code with its dependencies. So integration tests are generally slower to run, because there's more going on if the dependency happens to be my SQL than my SQL is going to be a bottleneck. They're harder to debug than unit tests, because there are more things that could go wrong along the way. So if a test fails, it could be my code, it could be my dependency, it could be my integration with the two. But that's not to say that they're not useful. They're extremely useful. They verify that things talk to each other. You know, pretty much anything you write is going to need to have integrations between pieces of code. So I want to verify that that works. They're also really good at defending against regressions. You know, I could have a developer that maybe, you know, didn't run the whole test suite. He changed his little unit of code. He pushed it. But the integration tests will run and tell me, oh, you actually broke something, because somebody else depended on you doing something in some way, and now you're doing it in some different way. And you know, I actually ignored costs. So I'm going to call the unit tests low cost tests, because they're fast to run and they're fast to debug.  And then we get to the big boy, the acceptance tests. This is what DHH wants to see. These are also known as system tests or functional tests. I'm going to call them acceptance tests. So here is my whole system. And so if this was a Rails app, maybe this would be my models, my views, my controllers with some my SQL and some Redis in there. And I'm going to test the whole system as one. So acceptance tests usually slow to run. I have yet to find an acceptance test that runs as fast as the unit test. They are by far the hardest to debug. Any single line that fails, there could be 11 things that fail underneath the hood.  And then sometimes it's just like, hey, this thing didn't show up on the page. Good luck. But they are useful. Again, they verify that business requirements are met. Acceptance tests are like, you know, many QA people in your automated test suite. And they run through and they click on stuff and they say, yep, the user can pay for a service or the user can create a blog post. And they do provide the most feedback about regressions. I mean, nothing else is going to be better than actually running the system and making sure it all works together. But because of their speed and because of their difficulty to work with, I'm going to call them high cost. So before I put it all together, I want to talk real quickly about risk assessment. So how do I find high risk code? This is the obvious one. This is the obvious high risk code. Any code that could cause bodily injury, economic laws, data laws, anything irreversible is bad, right? That's extremely high risk. There's no question about that. But there are two other things I would bring into high risk code. One is high traffic code. So if I have a system that requires my user to be logged in, the login page is extremely high traffic. And any bug, no matter how small, will be, will affect every user along the way. And so the effects of a small bug get multiplied because of the high traffic. And then also a very complex code is high risk. And the reason for that is if I have some code that, say, pulls in eight lists of users and collates them and then decorates them with more data and there's all this logic going on, and the code is complex because the domain is fundamentally complex, it's high risk because if another developer wants to come in and fix it, there's generally a high likelihood that they're going to break it, you know, because they need to get the entire context. And so when we put all of this together, how do we use the evaluation of risk and the evaluation of cost to put it all together? So high risk code, generally I want coverage at any cost. That's not to say I should just throw high cost tests at the problem, but I should be less concerned about having high cost tests covering high risk code. Low risk code, I definitely want low cost coverage. If I have to debug acceptance tests on something that says that the admin has a link to the admin page in the header, you know, that's generally a low risk feature and I don't want to have, you know, these complicated tests that I have to maintain covering them. And then, you know, there's code that lives in the middle and I want to have a balance. So, you know, the purpose of this talk is I want you to be able to go back when this conference is over and the hangovers are cured and you get back to work on Monday and I want you to ask yourself these questions. So, if you're not using test coverage metrics, can they be useful? There's a lot of good tools out there and, you know, with the caveats I mentioned, I think that they can be valuable. So, if you're not using them, I'd recommend considering it. If you are using them, I would recommend considering are you using them correctly? You know, are you focusing on the things with low coverage and are you still evaluating the things with high coverage and not trusting the metrics to tell you the answer? Have you evaluated what is the highest risk stuff? I mean, I'm sure that, you know, you know some of the high risk stuff intuitively like, can the user pay for my product? That's high risk because it's extremely high importance.  Do you find yourself getting stuck maintaining high cost tests? I know I have gotten stuck where I spent two days figuring out why these acceptance tests flake out on CI and why the developers have to run the suite three times to get a green pass. And then, you know, days and days get lost to this. And so, is the time that I'm spending doing that worth it? Is the test that's flaking out something that's testing something that's really not that important? Because if I spend four days fixing a test for something that's really minor, you know, that's not an efficient use of time. And so then with that, can I move my test coverage away from the higher cost tests toward some of the lower cost tests? And, you know, can I basically can I get the highest return on investment with the time I'm putting into my test coverage? And kind of to put all that all together, like the way I kind of emotionally feel about it is, you know, do I feel happy with my test coverage? I mean testing is supposed to make our lives easier, not harder. And, you know, is it, going back to what Uncle Bob said, is it giving me that confidence to deploy things and to change things? You know, is it making my life easier? So those are all the kinds of things I want you to think about. And, you know, if the result of this talk is that any of you maybe delete some of those unnecessary acceptance tests and maybe write some more tests around things that you realize are higher risk than you thought, I think that my mission will be done today. And so with that, I just want to say thank you for having me. Thanks to Stefan for organizing this event. Thanks to everybody for being here. And I'll take some questions. Yeah, what I would say is that, oh, sorry, it is kind of a long question. I'm going to try to restate it. Basically, the question was, in web development, the integrations are the most complex piece and the acceptance tests seem to be the best way of making sure that those integrations work together.  I agree with that.  I mean, so, you know, what are the integrations and can I test the integrations in smaller pieces? You know, rather than having to click around on the app and have, you know, these big test suites of clicking around on the app, you know, if I'm worried about how my controller and my database communicate, then I would maybe say, okay, I write controller tests that talk to the database and those are integration tests, right? And also, I was going to bring that up. If you write controller tests that talk to the database, that's not a unit test. A lot of people seem to have this misconception. It's a dependency. But, you know, if that's, that's the complex part, then I would test that. You know, if, if I've seen projects and this is kind of a question I don't have an answer to, but where I have a heavy JavaScript front end talking to an API, that's very hard to test just those pieces. And so a lot of times we depend on acceptance tests. And so I would say, you know, if that's the only way you can come up with, then yes, go for it. You know, that's how you're going to test that integration. But if you can maybe lock down the API and then create fixtures and then test the JavaScript alone against the API of your, of your, you know, backend, then that is a more efficient use of your time because now you have tests that run faster on both ends and you don't have these big cap bar tests along the way. That's a good question. I actually don't know any good coverage tools for JavaScript. I'm mostly familiar with the ones for Ruby, which are, there's a few services out there like code climate and a lot of them use SimpleCov under the hood, which is a jam out there. I'm not too familiar with what's available out there for JavaScript. But if there isn't anything, I recommend you write it because I think we could use more test coverage tools and especially something that can do something more. So a lot of the Ruby tools are limited by the fact that they do statement coverage and line coverage. And I think that we are lacking in both in Ruby in particular for branch coverage and condition coverage. Like testing in general or test coverage? Testing in general, I mean, that's such a wide topic. You search, if you Google Ruby testing, you will find a million good resources. I mean, Google pretty much helped me research this talk. There's so much out there. There's a lot of good blog posts out there. I know when I first learned Rails and I started to learn the TDE process, there's a, there are a couple great Ruby tutorials that are very heavy on doing the TDE style of Rails development and that really helped me kind of get started on seeing that and then, you know, kind of once you start to get comfortable testing. So, you know, if you're just starting testing, I would say, don't worry about this. Just start testing, right?  It's really kind of when you have a lot of test coverage and then you find yourselves getting bogged down in testing your app that, you know, you really need to start considering this risk versus cost analysis. So the question was, have I worked with third-party developers and had to get them to add test coverage? I have. So the approach I would take, so if you're starting out with code that has no coverage, you know, I think that you start with the high-risk code so you evaluate one of the highest risks. I mean, so first of all, they have to buy into the fact that that testing is good, right? Like, if they're not going to buy into that, then, you know, I'm not going to get anywhere. But if they've bought in that, hey, we want to add tests to my code, you know, you want to find the high-risk code first and you want to test that at any cost. There's a great book working with legacy software.  So what, you know, if I'm going to take an app that lets me pay for the service, that's, you know, probably the most important part. So I had a test, can I pay for the service? And then, you know, can I use the service if it's a blogging service, can I write a blog post? And you just kind of start to add those big tests. And then, you know, as you go further and further along, you can kind of start to add the lower risk and the lower cost tests along the way. All right. I think that's my time. Thank you very much.


This study on the carcinogenic risks associated with the intake of various meats estimated the risk was so great that we may not want to feed beef, pork, or chicken to kids more than like five times a month. This was in Europe, where lamb contamination is a particular problem. In the United States, if there was any standout, it would be chicken and PBDEs, flame retardant chemicals, not only compared to other meats, but other countries, U.S. chickens are like 10 to 20 times more contaminated than samples taken from other countries that have been tested. Though diet is not the only source of exposure, as those eating vegetarian have only about 25% lower levels in their bloodstream than those eating meat, though a large proportion of that may be from chicken. For other chemicals, diet may play a larger role. Studies of the pollutants in the breast milk of vegetarians dating back over 30 years have found the average vegetarian levels of some pollutants were only 1 to 2% as high as the national average. In fact, for the 6 out of 7 pollutants they looked at, there wasn't even overlap in the range of scores. The highest vegetarian value was lower than the lowest value obtained in the general population. This is presumed to be because these pollutants concentrate up the food chain, so biting lots from all the way down the food chain, plants, those eating vegetarian, may have an edge. For example, dioxins and meat, fish, and dairy believed to contribute almost all of the dioxin body exposure. And indeed, if you look at those eating strictly plant-based diets, I may only have about a third of the level of dioxins and PCBs, or even less than a fifth circulating throughout their bodies. This study really struck me. Asia has been facing a major problem of treating its millions of pounds of electronic waste every year, and these poor workers of these electronic waste recycling plants can be exposed to high levels of toxic chemicals, ending up with this kind of concentration of PCBs in their bloodstream twice as high as those living about 250 miles away along the coast. But these were non-vegetarian workers at the waste plant. The PCB levels of the vegetarians working at the same plant was even lower. The problem with these cross-sectional studies is that we can't single out the diet. It may be vegetarians of other lifestyle behaviors that protect them. You don't know until you put it to the test, change people's diets and see what happens. That's hard to do with persistent pollutants like PCBs, which may take literally decades to detoxify from the body. But we can get rid of heavy metals like mercury in a matter of months. And indeed, within three months of the exclusion of meat, poultry, fish, and eggs from their diets, there was a significant drop in the levels of toxic heavy metals in their bodies, including mercury, cadmium, and lead, up to about a 30% drop within three months. What if we just stick to organic meat? Certified organic meat comes from livestock that are fed with organically produced feed that is free from pesticides and animal byproducts and by law, and therefore one would assume that there should be a lower accumulation of chemical residues. However, on a practical level, there are simply no studies on the chemical residue content in organic meat. Until now, researchers acquired 76 samples of different kinds of meat, both organic and conventional, and quantified their levels of contamination with 33 different carcinogenic persistent organic pollutants. After all, the ingestion of food contributes more than 90% to the total current exposure to these compounds, especially food from animal origin. On the other hand, an increasing number of consumers are choosing organic. In fact, organic food production increased like 50% during the last decade, so are consumers of organic meat protected or not? Well, no sample was completely free of carcinogenic contaminants, which is to be expected, given how polluted our world is these days. But what was surprising was that the difference between organically and conventionally produced meats were minimal. Furthermore, the current pattern of meat consumption exceeded the maximum limits either way, strikingly the consumption of organically produced meat. Not only does it appear to diminish this carcinogenic risk, but was sometimes found to be even higher. The bottom line, sadly, is that the consumption of organic meat does not diminish the carcinogenic potential associated with the intake of these pollutants.


Hello and welcome to the Supreme Sport YouTube channel. My name is Joel and today I'm gonna be talking you through a session plan. I coach an under eights team and an under tens team. I've done this session with both groups. It works very well with both. I'd say this is actually fit from eight to 12 year olds. So if you are coaching any of those age groups, give this session a go. Let me know how it goes. Leave it in the comments, email us. I'd love to hear your feedback. So this session is working on link up play. My team sometimes struggled to create chances so I put this session together to try and fix that. Obviously it is gonna take time to see a vast improvement. I have seen a better understanding from my forwards on how to link up, create chances and score more goals. So this session is broken up into a warmup, a first drill, a progression of the first drill and then a match at the end where we can put what we've learned into a game situation. So let's get straight into this warmup. As you can see, there is not a lot of equipment used which is why I'm a really big fan of this session. All you need, I'd say either the maximum of five cones. So as you can see, I've got two lines of four, separated by these two cones here. Let's say the left-hand side will start with the ball. The person at the front of this cue will pass it onto the person in this cue. Once they've done this, they're gonna follow their pass onto this cue and then join the back of that line. Once the right-hand side's received the ball, they're gonna do the exact same thing. They're gonna pass it over to this cue and then follow their pass back onto this cue. It will keep a constant movement flowing. It's a very simple warmup. However, it is very good to get them passing early. Make sure their mistakes get out of them before we get into the drills. Make sure you're setting a good standard early on in the warmup because that creates good habits for the drills and the progressions and the matches. Obviously, this can get tedious and it's very important to keep their attention. This encourages them to chat less and they'll be interested in what you have to say. So to progress this, what I've did is I've got the fourth player on the right-hand side to join the middle here. They now have to pass to the player in the middle. Once the player in the middle has received the ball, the player in the cue is gonna make a run this way. The player in the middle then feeds it back to the person in the cue. The runner then passes the ball back into the other cue and then joins that line. So in short, they are doing a one-two with the player in the middle. A simple but effective and relevant warmup. If your team does struggle with this, encourage them to do it slowly to start off with so they get it correct. Once they get into the habit of not giving the ball away or any stray passes, then you can encourage them to pick up the pace. Now that your team's warmed up, we're gonna move on to the next drill. So moving on to the next drill. As you can see, I have two lines of four. My attackers are highlighted in blue. My defenders are highlighted in red. This drill focuses on their first touch and their finishing. Here's how it works. So the defender is always gonna start with the ball. The defender is gonna pass it to the front of the attacking cue. Once the attacker has received the ball, it then turns into a one-v-one between the attacker and the defender. And obviously, if they beat the defender, they have the keeper to beat. This puts them into good habits when they receive the ball after linking up with their forwards and encourages them to be much more direct. This is also a good exercise for your defenders because it works on their ball playing because they're passing it to the attacker and also they're jockeying. You can always make this competitive by adding a point scoring system. If the attacker score, it's a point to them. If they don't, the defenders get a point. Once you've let your team have a good go at this, you can progress it by adding yourself to the side. Defender starts with the ball, passes to the attacker. Once the attacker has his first touch, it then turns into a two-v-one. Now you can see how the warmup was relevant because he works on our one-twos. The attacker could pass it to me, for instance. The defender draws himself in, the attacker makes the run. I feed it to the attacker, the attacker scores. This is a really good way to focus on their movement and finish him. Now, if you really want to make it difficult for the attackers, you can even add two defenders because then when the attacker feeds the ball to me, one defender will press and one defender will jockey. This encourages the attacker to really think about the run that they have to make. For instance, they could come into here, I feed it, they score. Once the attackers have a good understanding of this, you take yourself out and let an attacker do your role. And that's it for the first drill. Let's move on to the progress version. So here is the progress version. As you can see, little to no cones have still been used. Let's talk through this one. So this time, the defender is gonna start with the ball through the middle cone. The defender will dribble the ball towards the goal and then have a shot. Once the defender has had his shot, he then has to high-five the goalkeeper. As soon as the defender high-fives the goalkeeper, they turn around and then it turns into a two-v-one between the front of each cue on the wide. Make sure you let each side take it in turns of who starts with the ball. So now the defender has drawn themselves out. We can do a one-two, he draws himself in, one-two, goal. Another possible way of scoring is if the attacker dribbles towards goal, the other attacker creates an option. The defender jockeys that attacker and when we have a shot, a goal on our own. This works on their decision-making, which is really important in the final third. It's also a great exercise for the defenders, allowing them to dribble, get comfortable with the ball, even have a shot, you know, defenders still can score goals. Also, testing their reactions in a two-v-one situation. Obviously, the attackers do have an advantage because it's a two-v-one, but if the defender gets it right, it will do their confidence a world of good. You can make this competitive by adding point scoring. However, I wouldn't totally recommend it because it might be a bit demoralising for the defenders because the attackers have such an advantage and it may lead to their confidence being knocked, which is not what you want. You can progress this by having two defenders go forward. Once one of them has high-fived the goalkeeper, we can have three attackers going forward, have one in the middle and one each flank. Try and make sure your middle player has the ball. This will really test their decision-making, making sure they find the right pass, whether it's this side, this side, depending where the defenders go, or having a shot or goal. Once you've done this, send them for a drink and then get them ready for the training match. Before you start the match, encourage your players to do what they've learned. You can do this by every time they do a one-two, it counts as an extra goal, or if they score with a one-two, it's double points. Either way, really try and encourage them to link up as a team. And once you've done this, you should be all done. After these drills, your team should have a much better understanding on passing movement, given goals and decision-making, and not to mention finishing as well, which will allow your team to score more goals and create more chances on the match day. So that is the end of the video. I hope you did enjoy. Feel free to give this session a go. Once again, let us know how it went. Let us know if your team improved. Even if you tweaked it to your own team's needs, we'd love to hear it. If you want more videos like this, hit the like button and make sure you subscribe for more content from myself. So last but not least, thank you very much for watching and have a great day. See you later.


Hello everyone, and welcome to this presentation. My name is Sia Vashriyahi, and today I will present the paper Two-Party Adapter Signatures from Identification Schemes. This is a joint work with Andreas Ewig, Sebastian Faust, Christina Ostakova, Monaziz Mitra, and me, Sia Vashriyahi. Andreas, Sebastian, Monaziz, and I are from Tuddamstadt in Germany, and Christina is from ETH Zurich in Switzerland. Okay, let's start with some motivation. Consider the following scenario. We have two parties, Alice and Bob, where Alice has a secret value W, which he would give to Bob in exchange for Bob's signature on a message. Bob, on the other hand, would give Alice a signature, but he would like to be sure that upon his signature being revealed, he would learn the witness W that Alice promised. And by revealed here, I mean that the signature is published on, for example, a bulletin board, a website, or a blockchain. Now, you might be asking, is this a scenario which happens in protocols, actually? And the answer is yes. There are many protocols over the blockchain that need to tackle with such an exchange. For example, we have conditional payments, atomic swaps, and payment channels, as examples. Let's see on a high level what type of protocol do we need in order to handle this exchange. So Alice and Bob would start to communicate with each other. Alice sent some message to Bob, Bob sends to you too. And eventually, Alice would like to be able to get a signature on the message M that she wanted from Bob. And she can extract the signature given the transcript of her communication with Bob and her witness. She can now, of course, send the signature and message pair to the blockchain. Bob would be able to get the signature from the blockchain. And Bob wants to, on the other hand, have the guarantee that given his transcript and the signature which he extracted from the blockchain, he would be able to get Alice's witness. A recent primitive called adapter signatures satisfy what I just described here. I will later in this call go into more details how adapter signatures work. But now I want to give you the history of adapter signatures first. Adapter signatures were introduced in March 2017 by Postera in a mailing list. He proposed a schnore-based construction for adapter signatures. A year later, Pedro Monero Sanchez and Anikid Kate proposed a threshold ECDSA-based variant of adapter signatures in a mailing list. In 2019, adapter signatures were used by MoloVolta et al. in order to construct payment channels. They, of course, require the threshold variant of adapter signatures. However, they did not formalize adapter signatures as a standalone primitive. It was first in 2020 that Aumaya et al. for the first time, proposed the formalization of a single-party adapter signature scheme and provided constructions based on schnore and ECDSA signatures. Later that year, Ezgin et al. et al. proposed two different post-quantum secure adapter signatures from different underlying assumptions. However, until this point, it was unclear from which class of signature schemes one can design and produce adapter signatures. It seemed a little bit ad hoc, the construction that were presented from schnore or ECDSA and it wasn't really clear if there is really an inherent property that can be used from signatures in order to transform them into adapter signatures. Furthermore, the threshold variant of adapter signatures was never formalized until this point. This brings us to our contribution. We know from the work by Klitz, Masny and Pan that ID scheme, identification schemes, can be generically transformed into signature schemes. I will call this class of signature schemes CIGID. In our work, we show how CIGID schemes can be transformed into adapter signatures, in the single-party case. Furthermore, we show how CIGID schemes can be transformed into two-party signature schemes and how these two-party signature schemes can be transformed into two-party adapter signature schemes. Note that our transformations are not generic and the underlying CIGID must satisfy some properties which I will go into more details later in this talk. Okay, now that I have given you some introduction and motivation, I will next follow with some background on adapter signatures, then give you the generic transformation in the single-party case and finally present our two-party adapter signature. Let's continue with some background. Adapter signatures in a more formal explanation work as follows. Alice has a pair of statement and witness where the statement and witness are from something which I call a hard relation, which means that given the statement, the witness cannot be extracted. Alice now sends the statement and the message for which she wants to receive the signature to Bob. Bob at this point generates something we call a pre-signature, a pre-signature which is basically an incomplete signature. Bob sends his pre-signature back to Alice and Alice can now verify if this pre-signature was indeed valid. If so, she would adapt this pre-signature to a full signature. This full signature looks just like a normal signature that Bob would have produced using his secret key. From the naked eye, it is not really clear for someone who just sees the signature that Alice and Bob actually executed an adapter signature protocol. Alice can of course now submit this message and signature pair to the blockchain. Bob would naturally be able to see it and he would be able to run an algorithm called extract which would give him a witness which is in relation with the original statement. So as you can see an adapter signature has four additional algorithms, pre-sign, pre-verify, adapt and extract. The high level idea when designing an adapter signature scheme is to hide this witness in the randomness used for signing. I will go into more details regarding this idea later but first I would like to give you the four properties that adapter signatures must satisfy in order for them to be called secure. The four properties are correctness, unforgeability, pre-signature, adaptability and witness extractability. Let's start with correctness. In correctness we have honest Alice and Bob who start executing the protocol honestly. Bob honestly generates a pre-signature. In this case we expect the pre-signature to be valid. Then Alice would of course adapt this pre-signature to a full signature and sends it to the blockchain. We again expect that the full signature generated in this case would be valid. Finally Bob would be able to extract a witness for the statement originally provided by Alice given the signature and pre-signature. Basically by correctness we just want everything to check out and the algorithm to behave as we expect them. A similar property which is a little bit different is pre-signature adaptability. Pre-signature adaptability is the situation where Alice is honest but Bob might be malicious. Alice sends a statement and message to Bob. Bob generates a pre-signature but he may actually deviate from the algorithm which generates the pre-signature. We want that if the pre-signature is valid and Alice adapts it to a full signature the resulting full signature is valid. So Bob cannot cheat by generating a valid pre-signature which cannot be adapted to a valid full signature. This is a guarantee for Alice because Alice wants to be sure that when getting a valid pre-signature she would actually be able to use it to get a valid signature and send that signature to somewhere as an evidence that Bob signed the message. Okay, let's continue to unforgeability. Unforgeability for adapter signatures is similar to unforgeability for normal signatures except the adversary has an additional capability. The adversary can get pre-signatures on his challenge messages. This means that the adversary should not be able to generate a valid signature on a message M even if he knows a pre-signature on the message M. This is a guarantee for Bob because Bob wants to be sure that no malicious party who is listening to his communication with Alice would be able to actually forge a signature on his behalf. Finally, let's talk about witness extractability. In witness extractability, Bob is honest and he's communicating with a malicious Alice. What Bob wants as a guarantee is that if Alice is able to generate a full signature, a valid full signature by executing this protocol, it should not hold that Bob is unable to extract a witness for the original statement. In other words, Alice should not be able to adapt the pre-signature in somewhat of a malicious way such that she would get a valid signature but Bob is not able to extract a witness. Okay, at this point I will stop talking about our background regarding adapter signatures and we'll continue with our generic transformation in a single party case. To present our generic transformation, I would start with how Schnorr adapter signatures work and then motivate how our transformation actually works. So let's recall what Schnorr is. Well, for Schnorr, we need a cyclic group of order, prime order Q and a hash function which maps elements to ZQ. The generation algorithm simply samples a random element from ZQ and the public key would be G to the power of X. Signing would start by sampling a random element from ZQ and computing G to the power of R. This would be the public randomness and R would be the private randomness. Then the signer computes the hash of G to the power of R, concatenated with M and this S would be R plus H times X. The whole signature would be the hash value plus S. Verifying would involve extracting the public randomness using G to the power of S times Pk to the power of minus H and seeing if hashing this R prime with M would result in the same hash value that the signature included. I will not open the statements here but you can verify that if the signature is valid, this would actually return G to the power of R. Now how can Schnorr signatures, signature scheme, be transformed into an adapter signature? Well, first let's say that the heart relation required for Schnorr is a deloc relation. So the statement would be G to the power of W and W would be an element from ZQ. The pre-signing algorithm simply differs with the signing algorithm in how the hash value is computed. Basically, instead of G to the power of R, G to the power of W times G to the power of R is computed. So we are shifting the public randomness with the offset W here. Verifying would also simply involve putting back this offset when computing R. Now what would we get as a pre-signature upon running this algorithm? Well, we would get R plus H of G to the power of W times G to the power of R. So as you can see, the randomness used here and here do not match the same way that it matched here. But you might already see how we can actually adapt this into a valid signature. We simply have to add the witness to this pre-signature because now the randomness used here and in the hash function are exactly the same. Exactly the same meaning that this value is now in the exponent. Extracting would also only involve subtracting the pre-signature and the signature. This brings me back to my high-level idea which I explained originally. The idea is to hide this witness in the public randomness used when generating the signature. But let's back up a little bit. What is a Schnur signature scheme? Schnur signatures are basically applying Fiat-Shamir heuristic to Schnur identification scheme. So if we do the translation to SIG ID, we would get the following. First, generate a private and public randomness, apply Fiat-Shamir heuristic, generate a signature. And for the verification, we simply need an algorithm that extracts the randomness, but that is given in SIG ID schemes. So it seems possible that SIG ID schemes may be able to be transformed into adapter signatures. Let's see how such a transformation would look like. Well, let's say we have a statement witness paired from a hard relation. Pre-signing would look as follows. Generate the randomness, shift the randomness and continue as in SIG ID, which means apply the Fiat-Shamir heuristic, generate the signature and output H and the pre-signature. For verifying the verification algorithm, first extract the randomness and then shift it. And checks if H is equal to the shifted randomness concatenated with M. Naturally, we would need two additional algorithms. Adapt, which would adapt the pre-signature into a full signature, and extract witness, which would extract the witness given a full signature and a pre-signature. Naturally, we cannot expect that this transformation would work for any hard relation and any SIG ID scheme. There must be some properties that these two, that the signature schemes must satisfy with respect to the hard relation. In more details, there are two properties that SIG ID schemes must satisfy for such a transformation to work. The property one is as follows. Let's say we have a pre-signature. We adapt it and then we extract the randomness from the adapted pre-signature. We would get some random value. On the other hand, if we first extract the randomness from the pre-signature and then shift this randomness, we expect to get the same random value. So if we adapt first and then extract, or if we extract first and then shift the randomness, we should get the same public randomness. This is, for example, necessary in order to prove pre-signature adaptability, where you have a valid pre-signature and you want to make sure that if you adapt it, you would get a valid final signature, a valid full signature. The second property is simpler than the first property. It simply states that if you adapt a pre-signature and then extract the witness from this signature and pre-signature pair, you would get the same witness as it was used originally in order to adapt. This is, of course, needed for, for example, proving extractability. Now, at this point, I will not go into more details regarding our single-party transformation of sig-id to adaptor signatures, and I would now summarize our contribution with respect to single-party adaptor signatures. First, I would like to point out that many signature schemes satisfy these two properties that I mentioned before. It is not only Schnorr, but, for example, Casvang and Julia Quizquat. So it was not a coincidence that Schnorr could have been turned into adaptor signatures. Actually, these other two schemes can also be transformed into adaptor signatures. Second, unique signatures such as BLS cannot be transformed into adaptor signatures because there is no randomness to actually play with in order to transform them into adaptor signatures. We actually proved this in our paper, and if you're interested in the proofs, please take a look at our full paper. Okay, let me continue to go to the final part of this talk and talk about two-party adaptor signatures. So what we saw by now, we saw that we can transform sig-id schemes into adaptor signatures. I will now talk how to transform sig-id schemes into two-party signature schemes and how we can transform two-party signature schemes into two-party adaptor signature schemes. I will not go into too much detail on how these transformations work. I will give a high level overview regarding them. If you're interested, you can check our full paper for more explanation. First, let me motivate why we need two-party signatures and adaptor signatures. There are some applications which require signatures from both parties. However, we would like to have a single signature instead of two signatures. So we don't want to get one signature from Alice, one signature from Bob, and concatenate them. We want to have a single signature on behalf of both parties. On the other hand, we do not wish to run a distributed key generation protocol because some applications would require Alice and Bob to generate such signatures time and time and time and again. And if you have to run a distributed key generation algorithm for every execution of the protocol, this would be quite inefficient. So what we want to have is that Alice would run her key generation algorithm separately, and Bob would do that also separately, so they have functioning secret and public keepers. But they would be able to generate a single signature after running a protocol, which is valid under the aggregated public keys. So the solution to what we want, basically a mechanism which Alice and Bob can use in order to generate a single signature without using distributed key generation, is two-party signature schemes with aggregated public keys. Now, let me show how we can transform CIGID schemes into two-party signatures with aggregated public keys. First, Alice and Bob need to exchange some randomness. This is a very traditional random exchange protocol where one party commits to the randomness, the other party then submits randomness, and they can open the commitment eventually. What they get after running this protocol is Alice would get her private randomness and two public random values, and Bob would also get his private randomness and two public random values. Then, both parties would generate a signature. How does this actually work? Well, first, the two public random values must be combined, then the Fiat-Chama heuristic must be applied, and then the signature can be generated as we discussed previously. Bob also does the same, but he uses his secret key. Alice uses her secret key. By this point, Alice and Bob both have the same hash value, but they have different SIs. They now exchange their SIs, and they would combine these two signatures that they had, and they would eventually get one full signature, which is valid under the aggregated public key. Now, the question is, how can this transformation, this two-party signature scheme, be transformed into a two-party adapter signature scheme? Well, the only thing that we need to change is to shift the randomness first before applying the Fiat-Chama heuristic, and that's it. Okay, I will not go into more details regarding two-party signatures and two-party adapter signatures from SIGID. If you're interested, please take a look at our full paper. Let me conclude the talk now. We actually analyzed which signature schemes can be transformed into adapter signatures, and we provided the generic transformation from SIGID schemes to adapter signatures. Furthermore, before the first time, formally defined what two-party adapter signatures are and provided the generic transformation from SIGID to two-party signatures and two-party adapter signatures. Now, the area of adapter signatures have gained a lot of attraction in the past few years, especially in the blockchain area, so there are many things that can be analyzed. Here, I would mention two future works. One would be to analyze other classes of signatures and see if they can be transformed into adapter signatures. For example, we can think about transforming signatures in the standard model from different assumptions, and by standard model, I mean that we are not in the random oracle model. Second, the main applications of adapter signatures by now have been in the blockchain area. It would be quite interesting to see if this primitive can actually be used in other areas, similar to the way that it was used in the blockchain area to solve some different problems. With this, I would like to thank you all for your attention, and if you have any questions, please feel free to contact me, any of the co-authors, or use the live session to ask your questions. Thank you very much. Thank you.


This episode is dedicated to all you truckers driving the boulevard, keeping our bellies full, shells stocked, septics cleaned, and brains entertained with what you're hauling. In the eyes of this ratchet jaw, I'm honored to have you listening. If you once in a while grab your CV, head to Sesame Street and tell other drivers how to join this weird oak convoy. Appreciate it. May your brake checks be few, your shutter trouble be absent, and your bare bites non-existent. Keep it cool on the stool. This is Spooky Santa and I'm 10 and on the side. Stories and content in Weird Darkness can be disturbing for some listeners and is intended for mature audiences only. Parental discretion is strongly advised. While many of us think of exorcisms as a thing for the movies, the fact is that many more real-life casting out of demons take place than we might think. Even the most well-known of such movies, The Exorcist, was inspired by real-life events. And what's more, the background to these real-life encounters with demonic entities from other realms and their attempts to take over the bodies of others is that they all differ greatly, both in circumstance and location. What is particularly interesting about many of these alleged cases of demonic possession that have led to attempts to perform exorcisms is that many of them have further reaching and often tragic consequences. Indeed, if we believe that part of possession is for a spirit to have a person do their bidding against their will and, at times, according to testimony, their knowledge, then many of the cases here could very well be argued to be demonic possession. However, there is also a fine line to tread, a line between recognizing mental illness and the medical treatment that could confront it and entertaining the possibility that something more unexplained and even otherworldly might be behind some of these fascinating, if grim, cases. I'm Darren Marlar and this is Weird Darkness. Welcome, Weirdos. This is Weird Darkness. Here you'll find stories of the paranormal, supernatural, legends, lore, the strange and bizarre, crime, conspiracy, mysterious, macabre, unsolved and unexplained. Coming up in this episode, demonic possession, it's real and sometimes even more terrifying than even Hollywood can portray. A demon can take hold in a variety of ways and show itself in a variety of forms. And sometimes, when a case is deemed to need an exorcism, the spiritual battle that takes place can appear worse than the possession itself, both during the exorcism and in its aftermath. If you're new here, welcome to the show. While you're listening, be sure to check out WeirdDarkness.com for merchandise, to visit sponsors you hear about during the show, sign up for my newsletter and her contests. Connect with me on social media. Plus, you can visit the Hope in the Darkness page if you're struggling with depression or dark thoughts. You can find all of that and more at WeirdDarkness.com.  While we clearly would not have the time to examine each and every case of apparent demonic possession that resulted in exorcisms, we can look at some of the most intriguing as well as accounts that had very real consequences, either for the person possessed or those around them. Perhaps the best place to start would be with the real-life events that inspired arguably the most famous film portraying possession and exorcism, The Exorcist. The movie was based on the book of the same name by William Peter Blatty and his inspiration came from two very real cases of demonic possession. It is claimed that one of the encounters occurred in 1949 in Cottage City, Maryland. Several newspaper articles appeared telling of the apparent demonic possession of a young boy, most often referred to as Robby in most articles. Not only had Robby become possessed, but he eventually underwent an exorcism thanks to a Jesuit priest. According to most accounts, Robby was from a German Lutheran family that had been introduced to spiritual interests through his Aunt Harriet, including the use of a Ouija board. However, following the death of his aunt, the entire family including Robby began to experience terrifying encounters and a surge of strange paranormal activity. Objects would suddenly lift into the air as if by a pair of invisible hands and strange noises could often be heard in the property. Furniture would also move across the floor completely under its own volition. Even more alarming were the episodes of levitation, where the young boy would float in the air unaided. It is thought by some researchers that the newspaper's source of information was the family's own pastor, Luther Myles Schultz. Instead, it was Schultz who the family turned to when the strange events began happening. One researcher and author who has extensively investigated the case is Thomas B. Allen, who would detail his findings in the book Possessed, The True Story of an Exorcism, and it is his research that provides much of what we know about the case today. I'll place a link to that book in the show notes. Following the start of these unsettling events, the family reported them to their pastor, Luther Myles Schultz, and asked him for his help. He agreed and arranged to have Robby stay at his home for the night, so he could observe him. This also gave Schultz the chance to see if the strange activity followed the young boy to his house. This would, in part, eliminate the possibility that events had been orchestrated by the boy or the family. It was reported that Schultz did indeed witness strange activity on the night Robby spent at the house. He claimed to have seen furniture and ornaments and other household items moving by themselves, as well as strange, unnerving noises. Ultimately, he advised the family that they should contact a Catholic priest and seek them to perform an exorcism. It is here where the story becomes a little murky. According to most accounts, several exorcisms were attempted over the following days and weeks, with most sources stating that at least one of these was performed by a Catholic priest, Edward Hughes. The exorcism was said to have taken place at the Jesuit Georgetown University Hospital. It is said that, during the evening, Robby, who was restrained for his own safety and everyone else's, freed himself and broke a bedspring from the mattress before proceeding to use it to slash Hughes' arm. Following the attack, the exorcism was immediately brought to a close. Following this first exorcism attempt, the family decided to take matters more into their own hands. They took Robby with them to St. Louis to visit relatives and to consult with a priest and professor at St. Louis University. After learning of the case, it was brought to the attention of Jesuit priest William Bodern, who made arrangements to visit the family while they were in St. Louis. He too would claim to have witnessed many strange events while in the house, including objects being thrown through the air and the bed shaking furiously of its own accord. Perhaps most disturbing, however, was the time the young boy would speak in a strange language in a voice that sounded unlike his own. After having witnessed the strange events, Bodern arranged for another exorcism to be performed, this time at the Alexian Brothers Hospital in St. Louis. Incidentally, one of the last surviving people who witnessed the events was Jesuit priest Walter Halloran, who was called in to assist Bodern with the exorcism. Remarkably, he would later attest to seeing such words as evil and hell appear on the young boy's body during the exorcism. There were, he would further claim, many other scratches and markings that appeared on his body as if out of nowhere. Those present also witnessed the mattress of the bed shaking uncontrollably. At one point, Robbie lashed out and broke Halloran's nose. The exorcism appeared to have worked, however, and according to the account, Robbie blended back into anonymity and was never bothered, at least to the best of public knowledge by such paranormal phenomena again. Speaking decades later before his death, though, Halloran stated that although he was there and that the events did happen, he could not go on the record to state that the boy was definitely possessed because he didn't feel he was qualified to do so. To some people, this was a discrete sign of skepticism on Halloran's part. Whether that is the case or not is not fully known. The case, though, is hard to pin down as completely factually accurate. Perhaps the best place to start when examining the validity of such claims is with the family's pastor, Luther Miles Schultz and the fact that he had an intense interest in parapsychology. While this isn't necessarily proof that he might have gone into the case with a biased mind and, intentionally or not, reported on things that were proof of strange phenomena, it is certainly a charge that has been leveled by skeptics, not least in light of the refusal by Halloran to confirm on record that the young boy was possessed by an evil spirit. It is perhaps worth noting that parapsychologist J.B. Rine was also at least partially skeptical of the events reported by Schultz, specifically those at his home, stating that it was possible that he unconsciously exaggerated some of the events that evening. We should also note, however, that strange paranormal happenings were witnessed by many people, with around 40 people being present for the eventual exorcism alone. One researcher who took an interest in the case and was ultimately very skeptical of the claims was Mark Obsasnik. He would highlight that Halloran, despite what had been reported, had not heard the boy's voice change to one that was not his own, and that Obsasnik suspected that the Latin phrases and words he used were likely ones he had heard from the priests themselves. He essentially believed that Robbie was merely an attention-seeking prankster who had orchestrated the events. Obsasnik would even highlight the words and scratches that suddenly appeared on the young boy's body. He noted how none of those present, including Halloran, checked Robbie's fingernails to see if he had in fact made the scratches himself. That something happened would appear to be not in doubt. Whether those events were of a true paranormal nature is perhaps open to debate. True or not, though, the reports of the events still served to inspire the movie The Exorcist. Truly unsettling events from 1634 in Loudoun also served to inspire Blatty. According to most accounts, several nuns claimed they were possessed by evil spirits following persistent illicit dreams they had concerning a particular priest named Urban Grandier. It is claimed that during the exorcism of these nuns, they made many blasphemous statements and even made sexual motions toward the priests themselves. These actions sound almost identical to some of the scenes in the movie and were undoubtedly responsible for influencing them. Perhaps an even more concern, Grandier was eventually arrested and accused of wrongdoing himself, being subject to various torture methods of the Church. Coming up, it's another famous and questionable case, one that is altogether a lot more harrowing and one that even disturbs me after hearing how it ends. That's next on Weird Darkness. Weird Darkness is now partnering with Paranormality Magazine. Paranormality Magazine is based out of love for the strange, unexplained and paranormal, as well as a fascination with the people and creators that make the paranormal community what it is. Exploring all 40 subjects, from phantoms to UFOs and every cryptid creature in between, their global team collects stories, conducts interviews and reports on cutting-edge paranormal projects. They also consider contributions from outside writers, researchers and artists. Visit WeirdDarkness.com slash magazine to learn more or subscribe to Paranormality Magazine. That's WeirdDarkness.com slash magazine. And you can get 10% off your subscription if you use the promo code Weird. That's WeirdDarkness.com slash magazine promo code Weird. WeirdDarkness.com slash magazine promo code Weird. The only thing more spooky than Halloween in October is Spooky Empire. Join me on October 27th through the 29th in Orlando, Florida to meet horror celebrities like a nightmare on Elm Street's Freddy Krueger, Robert England and co-star Heather Langingham. Hellraiser's Doug Pinhead Bradley will be there with other casts from the film, Candyman's Tony Todd, an American werewolf in London's David Moughton, the cryptkeeper John Kassier, Rose McGowan from Charmed in Death Proof, Kane Hodder from the Friday the 13th films, Harry Hamlin from Clash of the Titans and so many more including Cassandra Peterson, better known as Elvira Mistress of the Dark. Get autographs, take photos and hear Q&A sessions with your favorite horror celebs. They've even asked me to moderate a few celebrity Q&As too. You'll also find horror-themed workshops like making movie props and makeup, horror writing and more. Get all the details, see a full list of celebrities and grab your tickets at spookyempire.com. That's spookyempire.com and I hope to see you there October 27th through the 29th in Orlando, Florida. The apparent possession and exorcism of Annalise McKell in Bavaria, West Germany in 1975 and 1976 also inspired several movies, perhaps the most well-known being the exorcism of Emily Rose in 2005, almost three decades after the ultimately tragic events unfolded. McKell grew up in a Catholic family who were particularly strict in their beliefs but largely had a normal upbringing. Then for no reason that could be determined, when she was 16 years old she suddenly blacked out at school. Following this episode she appeared to be in a permanent daze or trance. When she finally returned to normal she claimed to have no recollection that anything strange had happened. The incident was largely forgotten about until a year later when she again awoke in a strange trance-like state, this time convulsing and even wetting the bed. Once more she recalled no memory of the episode when she came to but her family now looked to seek medical help. She was ultimately diagnosed with temporal lobe epilepsy. This condition causes blackouts, seizures and on occasion hallucinations. With regular medication her condition could be controlled and she continued her education at the University of Wurzburg. However, as her first year unfolded in 1973 the drugs began to fail increasingly and she became more and more withdrawn. Even worse she was beginning to hallucinate strange devil faces watching her as well as hearing voices telling her she was damned. It was during this time that Annalise began to increasingly believe that a demonic entity had possessed her, one that was becoming more and more powerful as the days and weeks went on and what's more she believed it was a problem that medication couldn't help with. It was noted by those around her that Annalise was increasingly unable to enter Christian buildings or even be near Christian symbols such as a crucifix, in part due to her own rantings as well as the observations of friends and family others began to consider that she might in fact be possessed by some evil force. Both Annalise and several family members approached multiple priests to examine the case and perform an exorcism. However, all would decline stating that it was in her best interests to continue with medical treatment and that she should return to the doctor to alter her medication. Perhaps because of this refusal or perhaps whatever entity had taken control of her, if indeed that was the case, her mental state and overall condition began to deteriorate rapidly and she would act in the most extreme way. She would, for example, tear her clothes from her body at random moments or carry out hundreds of squats without stopping. On other occasions she would hide under the table or behind furniture, often making animal noises.  As a result of this continuing and escalating behavior, the family sought the help of another priest. Only this time the priest in question, Ernst Alt, agreed that she was possessed by an evil spirit and claimed that an exorcism was warranted. It would be a claim that would be examined years later in a court of law. Ernst Alt would seek permission from his local bishop, Joseph Stangel, to perform an exorcism on Annalise. His request was granted.  What followed was a ten-month period during which dozens of exorcisms were performed, with some of these lasting upwards of four hours at a time. Some of the revelations of these exorcisms were as bizarre as they were thought-provoking. Not least the assertion put forward by Annalise herself that she was possessed by no less than six demons, each of which she named Lucifer, Cain, Judas Iscariot, Adolf Hitler, Miro, and a disgraced priest named Fleischmann. She further claimed that these entities were jostling between themselves to fully take over her body. As intriguing an idea as it might be that such specific historical figures might be behind attempts to possess a person, it may be a red flag that Annalise's problems were more mental than paranormal, or at least her perception of them. This is something we'll return to shortly. Perhaps more unnerving though was the repeated ideas from Annalise that she should die to, quote, a tone for the wayward youth of the day and the apostate priests of the modern church, unquote. As the exorcisms went on, Annalise's condition continued to decline. She would eat less and less, eventually stopping altogether. She had to be restrained, physically so, for most of the exorcisms and she even broke the bones in her knees from the vast numbers of hours she spent knelt praying. In total, 67 separate exorcisms were carried out on Annalise before her death on July 1, 1976. It was determined that she had died from dehydration and malnutrition. Essentially, intentionally or not, she had been starved to death. And a little over 18 months after her tragic demise, the circumstances around her death and, more specifically, those who were around in her final months would find themselves at the center of a legal court trial. Following the investigation into her death, her parents, as well as the two priests, Ernst Alt and Arnold Renz, were arrested and charged with negligent homicide. In short, their actions and failure to intervene and seek medical assistance, particularly when the young woman stopped eating, had directly resulted in her death. The case came to trial in March 1978 and had captured the interest of the entire country. And the picture painted by the prosecution was not a pretty one. They claimed that it was clear that Annalise was not possessed and that her belief that she was possessed came from a combination of her temporal lobe epilepsy, which, remember, she had been diagnosed with and her upbringing in such a strict, unforgiving religious environment. While the defense argued that the exorcisms had been legal and protected under the country's rights to religious beliefs, even the bishop who had authorized the exorcisms to go ahead distanced himself from them, stating that if he had been aware of Annalise's medical diagnosis, he would not have given permission for them to go ahead. All of those accused were found guilty of the charges. What's more, they were each given suspended prison sentences. What's interesting about this, especially as the case that sparked intense debate in the West German media about the church's outdated attitude to what was essentially mental illness, is that these sentences were much more than what the prosecution had asked for, which was merely a fine and a guilty verdict. It showed how seriously the authorities were looking at such attitudes from the Catholic Church and almost certainly as a result, the number of exorcisms authorized in the country dropped dramatically. Ultimately, whether Annalise was possessed or not and it was the prosecution's assertion that she wasn't, there were ample occasions where intervention from either her parents or either of the priests could have saved her life, even in the final days. In a strange twist of sorts, decades after the case, on June 6, 2013, the house in which Annalise lived and where she endured the months of torturous exorcisms suffered a significant fire. And while the damage was repairable and judged to be a case of arson, many rumors began to swirl that the flames were caused by her spirit and must still reside within the walls of the building. Around the same time as the Annalise-Mckel case across the English Channel in Osset in West Yorkshire in England, another similarly disturbing encounter unfolded. The incident involved a butcher, Michael Taylor, who had been displaying questionable behavior throughout much of 1974. Although most knew him as a kind, married man and the father of five children, he also suffered from bouts of depression, in part due to his persistent back trouble. Although the tailors were not particularly religious, many of the local town were, and a friend of the family suggested they join them at a church group meeting, the Christian Fellowship Group, in an effort to help Michael's depression. Much to his wife Christine's surprise, Michael appeared to take to the group, attending regularly and being an active contributor. He particularly struck up a relationship with the group's 21-year-old pastor, Marie Robinson, who was 10 years his junior. In fact, he spent so much time with Marie that his wife would eventually confide in other members of the group that she believed he had desires of having an affair with her. When it came to light that he and Marie had engaged in several private rituals involving only the two of them, Christine only became all the more concerned, even more so when she learned that these rituals only took place when there was a full moon. As Michael spent less and less time at home at an increasing amount of time with Marie, Christine, feeling more and more desperate, put her concerns to Michael at one of the group meetings in front of all those present. It is at this point when the tail really takes a dramatic turn. Michael would claim that an evil influence had cast a shadow over him before going on to launch a volatile verbal assault on Marie. At one point, he went to physically attack her and had to be restrained by other members of the group. For her part, Marie would say that she saw his whole features change right before her eyes and that he had become almost bestial with a really wild look in his eyes. Perhaps amazingly, Michael would later claim to have no memory of the incident. Ultimately, the group forgave him for the outburst and the matter was officially at least put to bed. However, the worst was still to come. Despite their efforts to forget about the bizarre episodes, it quickly became apparent to all those in the group that there was something wrong with Michael. What's more, rather than getting better or even stabilizing, he was clearly becoming worse. When local ministers were asked to overlook the situation, the genuine question of whether he might indeed be possessed by a demonic entity was discussed, and ultimately it was decided that an exorcism would be in his best interests. Two of the ministers themselves would perform the exorcism, Peter Vincent and Raymond Smith, which took place just short of midnight on October 5, 1974 at St. Thames Church in Barnsley. Throughout the exorcism, Michael would react violently, convulsing, spitting and screaming obscenities. The exorcism lasted right into the next morning, during which time some questionable activities were carried out, such as pushing a crucifix forcibly into his mouth and drenching him repeatedly with holy water. After several hours of this, Michael had become almost animalistic, lashing out and even growling at anyone who approached him. Several members of the group were present and later attested to such events. They claimed there were over 40 spiritual entities inside Michael and that while they had managed to cast out most of them, several remained. After eight hours of the session, the two priests had to halt the proceedings due to exhaustion. They suggested that both Michael and Christine should rest and they would begin the exorcism again the following day. It was an exorcism that never happened. At just before 10 am, on October 7, PC Ian Walker was driving his patrol car down the street upon which the tailors lived. To his shock there in the middle of the road, naked, looking confused and covered in blood, was Michael Taylor. As Walker stopped the car and cautiously approached Taylor, he lay on the ground and curled up. Walker recalled he was saying repeatedly, quote, it is the blood of Satan, unquote. By the time Walker had taken in more of the activity on the street, he noticed another police car already parked outside the property. He learned that neighbors had called the police due to a disturbance coming from the Taylor house. When the policeman walked toward the property, he suddenly saw his inspector rush out the front door. He stood there a moment and then doubled over and vomited. He would offer to Walker that he, quote, didn't want to see this one, unquote, continuing that he had never seen nothing like it before. He would further elaborate that whatever Taylor had done, he had ripped at her and that there was not much of her left. When Walker stepped inside despite his inspector's warning, he realized that the her in question was Christine Taylor, Michael's wife. The living room was a scene of absolute chaos and destruction, with blood splattered and washed upon almost every wall and surface. It was also what appeared to be brain matter on the floor. Close by was the body of Christine Taylor and the family dog. Each of them was barely recognizable. It would later come to light that around 9.30 a.m., only minutes before the arrival of the police car and then PC Walker, Michael Taylor had strangled his wife before tearing and clawing at her face, almost tearing it off completely. Both of her eyes were completely gouged out, and her tongue was ripped from her jaw. Parts of the bone of the face were clearly visible from what must have been a frenzied attack. Their unfortunate pet dog had seemingly suffered a similar brutal attack, with damage to all four of its limbs. Needless to say, Michael was arrested and taken into custody. Once there, he would begin to reveal just what had happened and why. When they asked Michael to tell them what had happened, he began by telling them of the exorcism the previous day. According to police records of his statement, he would state that those who had performed the exorcism had danced around him and kept him in the church all the way through the night. Then he would state the power was in him and that he couldn't get rid of it and neither could they. It was perhaps the last part of that initial response that was the most chilling. He would offer to the officers that it was too late and that he was, quote, compelled by a force within me to destroy everything living within the house. During the course of the questioning, he would claim that he loved his wife deeply and could remember nothing whatsoever about the attack. However, when he was asked how he felt right then at that moment, he would reply, perhaps ominously, that he felt released and that the evil in her has been destroyed. He was swiftly charged with Christine's murder and remanded in custody to await trial. The crime quickly drew national attention from the newspapers and given the background to the case, combined with the recently released film The Exorcist, many people took an intense interest in the upcoming trial. The trial itself began in March 1975 and Michael again testifying in his defense claimed that he had no memory of killing his wife and that he was under the influence of dark, evil forces. He further offered, whether sincere or not, that his wife, whom he claimed to have loved dearly, was also possessed by an evil entity. His defense also turned their attention to the Christian Fellowship Prayer Group, who they essentially likened to a cult and went further claiming that the group had lit the fuse of the eventual horrific murder with their warped religious ideals. Defense lawyer Mr. Ognal would be particularly blunt when he stated that, quote, we submit the tailor is a mere cipher. The real guilt lies elsewhere. Religion is the key. Those who have been referred to in evidence and those clerics in particular should be with him in spirit now in this building and each day he is incarcerated in Broadbore and not least on the day he must endure the bitter reunion with his five motherless children, unquote. Powerful words no doubt might they be accurate. Might the private rituals between Marie Robinson have been a catalyst of sorts that resulted in murder? Just what were these rituals and why did they take place? And what of the eager nature with which the local ministers went ahead with an exorcism, an exorcism that appears to be more in line with the methods of the inquisition of the Dark Ages? Whatever the case, Michael Taylor was ultimately found not guilty of murder due to reason of insanity. He was sentenced to two years in Broadbore Secure Hospital, legally declared insane by the state. After these two years, he was transferred to Bradford Royal Infirmary and was ultimately released back into the public in the early 1980s. We have to ask if Michael Taylor was suffering from genuine insanity, was he really rehabilitated to a satisfactory degree in just four years? And above all else, was he really possessed by an evil entity that temporarily took over his thoughts and actions for its own ends? Or were these blackouts genuine signs of mental illness on Taylor's part? It is perhaps worth noting that Taylor was brought back before the court in 2005 on the charge of indecently touching a teenager and was ultimately ordered back into psychiatric care once more. What's interesting about this grim affair is Taylor had said to the police when he was arrested that it was all his fault and asked if he was going back to Broadmoor for killing his wife. He had by all accounts continued to display on behavior when he returned to live in Osset following his release back into society. And he would seemingly continue to suffer from depression, even attempting to commit suicide on at least four separate occasions. Was Michael Taylor mentally unwell so much that at one stage he blacked out and brutally murdered his wife, a woman he maintained he deeply loved decades after her murder? Or was he really subjected to the powers of some dark force that overtook him completely, leaving him no memory of the attack his body had been used to carry out? It is a case that continues to fascinate many in different fields, from those of psychiatry and criminology, and those who contemplate that the notion of demonic possession has more validity to it than many people would like to even consider. Incidentally, the attempted exorcism of Michael Taylor was the last such ritual connected to the Anglican Church, at least officially, which came under quite an attack from commentators and the general public. And while they stand their ground, as well as distancing themselves from the notion of exorcisms, there is little doubt that the entire episode reflected badly on them. Much earlier than the other exorcisms we have examined so far is another such casting out that took place in 1912 in Milwaukee, Wisconsin, with the exorcism of Anna Eklund. In truth, although the first exorcism took place in 1912, the bizarre events stretched back some years. Perhaps the first rumblings that strange events were heading their way came as far back as the late 1890s when Anna was still a teenager. During this time, she would suddenly begin withdrawing from any religious symbols or books and could not physically bring herself to even step into a church.  Furthermore, she would often speak in languages that she didn't know, including Latin and German. A decade later in 1908 and after a steady continuous decline in her behavior, another apparent revelation swept through the Milwaukee community. According to this new information, the girl's father and her aunt practiced witchcraft and it was they who were responsible for her blasphemous behavior. Ultimately, several medical professionals examined Anna but could find no physical or psychiatric reason for her displays. By 1912, with all other apparent avenues exhausted, the family and local community would turn to the church for help. An exorcism was granted and was performed by Father Theophilus Reisinger. Initially, it appeared as though the exorcism had been a success. However, after several months, the strange happenings surrounding Anna returned and they were even worse than before. Local rumors swirled that Anna's father and aunt were once again behind the strange encounters of the terrified young woman, claiming they had put some kind of spell or curse on her from afar. These bizarre experiences would go on for almost 20 years until in 1928, Anna, desperate for help, turned to Father Reisinger for help once more. Reisinger would agree to help Anna. He would also request several other priests adept in exorcism to help him in his attempts to cast out this evil presence once and for all. The exorcism would take place on August 17, 1928 at a Franciscan sisters convent. And according to the records of the event, the activity was immediate and intense. Anna immediately reacted badly to the holy water and recoiled away from crosses. Even more unsettling, she would often make hissing noises like a cat about to strike and at one point was claimed to have walked up the walls like a spider before being forced down and restrained on the bed. Even once restrained, she still managed to levitate a considerable distance from the bed. Throughout the exorcism, she would let out howls and screams and she would vomit an ominous liquid. Even more alarming though were the physical changes to her appearance that were witnessed by those present. Her head and lips swelled noticeably while her eyes bulged in their sockets in an unnatural way. Some people reported that her entire body appeared to increase in size right before their eyes, before returning to its normal dimensions. And this happened on several different occasions. There were three separate exorcisms in total, which took place over a period of 23 days. During the course of those sessions, the priests believed that at least four different spirits were seeking to take possession of Anna's body, with one of these claiming to be Bill's above himself. However, it was two of the lesser known spirits that were perhaps most revealing. It was believed that they were the spirits of her father and aunt who had since passed away. It would appear, despite the intense nature of the exorcisms, that they were ultimately successful and Anna suddenly sat up as if she had been snapped out of a trance. Her case is perhaps one of the most credible on record and certainly one that warrants further study. Up next, it's a 2008 case where the church actually turned the demon-possessed person away, handing her off to mental health practitioners. At first, anyway. A creature, part of the darkness before God created the heavens and earth, has awakened. It had slumbered, hibernating from the light. Now it's hungry and wanting to feed.  Everyone in the small town of Standard Illinois is turning to former Chicago cop Rob Aletto to find them. But as he starts his search, more people disappear. Rob is quickly overwhelmed. The night itself seems to come alive, taking these people. Aletto must find out why and discover a way to stop it before the entire town slips into darkness. Into Darkness by Jason R. Davis, narrated by Weird Darkness host Darren Marlar, the greatly anticipated sequel to Inside the Mirrors. Hear a free sample on the audiobooks page at WeirdDarkness.com. WeirdDarkness is lacking, as is any scientific proof, but he still exists and is still seen. And now, you can search for Bigfoot every month in the Find Bigfoot calendar by Timothy Wayne Williams. Each month, you'll be captivated by an original Timothy Wayne Williams painting, beautiful and captivating. But within each painting hides a monster. Bigfoot is hiding somewhere in each painting. Search for Bigfoot and invite others to do so as well with the new Find Bigfoot calendar available now at WeirdDarkness.com Without a doubt, one of the most intriguing cases of apparent demonic possession happened in more recent times, in 2008, when a woman in New York referred to in reports as Julia approached her church claiming she was possessed by an unknown spirit. Unable to help, the church would turn to psychiatrists for their opinion on the matter. One such person who learned of the case was Dr. Richard Gallagher, the associate professor of clinical psychiatry at New York Medical College. He would interview Julia and investigate the background to her claims. Amazingly, he began to suspect that Julia wasn't making the whole thing up, nor could mental illness explain the bizarre happenings. For example, Julia would often respond to his questions in voices that were clearly not her own. She would also behave in drastically different ways to her usual demeanor. Strangest of all, any kind of religious artifact or symbol caused her to recoil. Gallagher also noted that Julia would go into trance-like states, and it was often while in these states that vile language and threats were made, often in voices that were clearly not hers. He would elaborate that these voices were often guttural and vaguely masculine. Perhaps most disturbing to Dr. Gallagher though was that during phone conversations he would have, these same strange voices would appear on the line out of nowhere and then disappear again. He convinced more than ever that Julia was experiencing something of a paranormal nature and exorcism was arranged which Gallagher attended. What he witnessed that evening would turn his belief system on its head. As the exorcism progressed, Gallagher witnessed Julia levitate while the room itself would become intensely hot. Items would also fly off shelves while Julia herself would speak in different languages and even demonstrate personal details of those in attendance. Even stranger, when normal water was sprinkled over her, she was unconcerned. But when the same thing was done with holy, blessed water, something that she had not known, she reacted violently. Perhaps most remarkable though was that after the exorcism, she appeared to be free of whatever demon or spirit had taken hold of her. Although he couldn't explain them, Dr. Gallagher, a man of mainstream science, was convinced that the encounter was something truly out of the ordinary and unexplainable. As we can see then, while there are certainly some cases where possession may not have been the cause of some of the bizarre behavior we've examined, others cannot so easily be dismissed. Of course, whether that means that the notion of a person being overtaken by an evil spirit or entity is accurate or whether it's the result of the complexities of the human mind remains open to debate. Perhaps the idea of demonic possession is so far removed from the 21st century thought process that the notion is immediately dismissed without consideration. Indeed, what was and currently still is, at least to some, still regarded as essential dark magic and occult powers may one day eventually be explained by science. Of course, whether that means our understanding of possession shifts our collective scientific perspective is perhaps yet to be determined. The cold hard fact of the matter is that belief in demonic possession remains in place right across the world, if only to some people. And more often than not, many people who claim or are believed to be possessed are subjected to harsh, often unforgiving and tragic rituals. Rituals from which they sometimes don't survive. Thanks for listening and be sure to stick around for the bloopers at the end. If you'd like to learn more about the dangers of demons and what to do about them, I presented a half-hour message on this topic back in November of 2022 in my other podcast, Church of the Undead. I'll place a link to the episode in the show notes if you'd like to listen to it. If you like Weird Darkness, please share it with someone you know who loves the paranormal or strange stories, true crime, monsters or unsolved mysteries like you do. You can email me anytime with your questions or comments at darren at WeirdDarkness.com. WeirdDarkness.com is also where you can find information on any of the sponsors you heard about during the show, find all of my social media, listen to audiobooks I've narrated, sign up for the email newsletter, find other podcasts that I host, including Church of the Undead, visit the store for Weird Darkness merchandise and more. WeirdDarkness.com is also where you can find the hope in the darkness page if you or someone you know is struggling with depression or dark thoughts. Also on the website, if you have a true paranormal or creepy tale to tell, you can click on Tell Your Story. You can find all of that and more at WeirdDarkness.com. All stories on Weird Darkness are purported to be true unless stated otherwise, and you can find links to the stories or the authors in the show notes. Demon possession and exorcisms was written by Marcus Louth for UFO Insight. Weird Darkness is a registered trademark. Copyright, Weird Darkness. And now that we're coming out of the dark, I'll leave you with a little light. Ephesians 6, verse 12, For we do not wrestle against flesh and blood, but against the rulers, against the authorities, against the cosmic powers over this present darkness, against the spiritual forces of evil in the heavenly places. And a final thought.   His attack is psychological, Damian, and powerful. William Peter Blatty, author of The Exorcist. I'm Darren Marlar. Thanks for joining me in the Weird Darkness. Freed himself and broke a bedspring from the mattress before proceeding to freed himself and broke a bedstring. One researcher who took an interest in the case and was ultimately very skeptical of the claims was Mark Upsesnik. Upsesnik? Upsesnik? And that Upsesnik and that Upsesnik and that Upsesnik being subject to various torture messages? Yes, torture messages. Not torture methods, torture messages. Right. Like those notes that you get in school from the cheerleaders that say, no, I will not go to prom with you. I know you didn't ask me, but I thought I'd go ahead and head that off at the pass. Torture messages. Alright. Torture methods. Let's try it again. Let's try it again.