

The huge data breach serves as a reminder of some basic security tips

Credit: Yahoo


That's because Yahoo, unlike MySpace, LinkedIn and other online services that suffered large breaches in recent years, is an email provider; and email accounts are central to users' online lives. Not only are email addresses used for private communications, but they serve as recovery points and log-in credentials for accounts on many other websites.

An email compromise is one of the worst data breaches that a person could experience online, so here's what you should know:

Fifty shades of hashing

Yahoo said that the "vast majority" of the stolen account passwords were hashed with bcrypt. Hashing is a one-way cryptographic operation that transforms data into a set of random-looking characters that serves as its unique representation -- this is called a hash.

Hashes are not supposed to be reversible, so they're a good way to store passwords. You take input, such as a password, pass it through a hashing algorithm and compare it to a previously stored hash.


Unlike the ageing MD5, which is quite easy to crack if implemented without additional security measures, bcrypt is considered a much stronger algorithm. This means that in theory, the likelihood of hackers cracking "the vast majority" of Yahoo passwords is very low.

But here's the problem: Yahoo's wording suggests that most, but not all passwords were hashed with bcrypt. We don't know how many passwords were hashed with another algorithm, or which one it was. The fact that this hasn't been specified in Yahoo's announcement or FAQ page suggests that it's an algorithm that's weaker than bcrypt and that the company didn't want to give away that information to attackers.


Don't keep emails just because you can



If you're among the people who don't delete welcome emails and other automatic notifications sent by websites, such as password resets, then you might want to consider doing so and even go back to clean your mailbox of such communications.


Be careful when asked for your personal details



Also, don't provide real answers to security questions, if you can avoid it. Make something up that you can remember and use that as answer. In fact, Yahoo doesn't even recommend using security questions anymore, so you can go into your account's security settings and delete them.

Check your email forwarding rules regularly

Email forwarding is one of those "set it and forget it" features. The option is buried somewhere in the email account settings that you never check and if it's turned on there's little to no indication that it's active.


Two-factor authentication everywhere

Turn on two-factor authentication -- this is sometimes called two-step verification -- for any account that supports it. This will prompt the online service to ask for a one-time-use code sent via text message or generated by a smartphone app, in addition to the regular password, when you try to access the account from a new device.


Don't reuse passwords; just don't

There are many secure password management solutions available today that work across different platforms. There's really no excuse for not having unique, complex passwords for every single account that you own. If you do want memorable passwords for a few critical accounts use passphrases instead: sentences made up of words, numbers and even punctuation marks.

Here comes phishing


These emails can masquerade as security notifications, can contain instructions to download malicious programs that are passed as security tools, can direct users to websites that ask them for additional information under the guise of "verifying" their accounts and so on.


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