Polynomial

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Pentester, ex-developer, security researcher, reverse engineer, electronics tinkerer, internet activist, zombie eradicator, promulgator of useless facts, shrubbery inspector, bacon aficionado, devourer of donuts.

Strengths: Security, Crypto, Win32 API, C#, .NET, PHP, x86 assembly

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Opinions are my own. Advice provided with no warranty.

	32,822 reputation	bio	website	en.wikipedia.org/wiki/…	visits	member for	1 year, 7 months
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Jul 23	comment	Does the salt need to be unique or not predictable? Too much to discuss in comments, so I posted stuff to a pastebin: pastebin.com/raw.php?i=Hein4cy0
Jul 23	comment	Does the salt need to be unique or not predictable? Making the salt hidden just turns it into a pepper. The point of a salt is to make each hash unique. The point of a pepper is to make it impossible to crack passwords with SQL-only access. You're trying to protect yourself against all attackers. All you're doing, in your scheme, is making the salt the pepper and vice versa, then using a predictable salt. It provides no benefit at all. In fact, it's less secure. Just generate a random unpredictable salt, and have a constant long random pepper.
Jul 23	comment	Writing exploit code that bypasses IPS detection This doesn't really answer the question. OP wasn't asking for IDS recommendations.
Jul 23	comment	Does the salt need to be unique or not predictable? Well the `userID` is predictable if it's an auto-increment. Can you guarantee to never leak a user's ID? The reason for mixing pass + pepper is that the salt for bcrypt is automatically generated, so it's easier to implement. You should not hard-code the salt, since it is an integral part of the security of bcrypt. The same goes for PBKDF2, since it uses HMAC, where the salt becomes the key. It must be unique. The pepper is only there for obfuscation purposes, as an extra defense against the SQL injection model of attackers.
Jul 22	comment	How to store salt? @apfel Read my answer. It explains why salts should be random and non-public. Your answer also doesn't explain why we salt, or why we don't need to obfuscate the salt.
Jul 22	comment	How to store salt? @GarrettAlbright I mentioned scrypt in the second-to-last paragraph. The only downside with Scrypt is that there aren't as many libraries available, and there hasn't been much study of it. Right now I'd suggest bcrypt, since FPGA-based cracking engines are not a security concern for most people, but when scrypt has been studied carefully by a few cryptographers I'd be happy to tell people to use it instead.
Jul 21	comment	I may have given a check to a scam organization is my account at risk I also suggest you talk to the police. Scams like this are highly illegal - falling under the jurisdiction of the FBI (US) or SOCA (UK). Agencies have got a huge database of these kinds of scams, and can often actually identify the groups likely to be responsible. They also will be able to give you lots of good advice and reasonable expectations for what they might do with your data. Also, if the bad guys do manage to steal money from your account, a police incident number can do wonders for an insurance claim.
Jul 21	comment	Does the salt need to be unique or not predictable? PBKDF2 is still pretty good. GPUs accelerate it massively, but your security margin is still greater than your performance hit. Even if the GPU can do SHA256 ten thousand times faster than your CPU, you only have to compute one hash, but the attacker has to compute billions. I agree that bcrypt is better, though.
Jul 21	comment	What is the application of SHA384withRSAEncryption? It's not used to store password hashes. It's used to verify the authenticity and integrity of arbitrary data in the database. For passwords, use bcrypt.
Jul 20	comment	To salt, or not to salt? Keep in mind that you should use a non-public value for a salt, as I describe here. The salt should not be any more public than the password hash. If the salt is available, you're vulnerable to attacks using single-salt rainbow tables which give you no time to respond to a breach.
Jul 20	comment	Is it wrong to collect and store IP addresses? I'd count them as personal information, especially if you're storing them against records of activity.
Jul 20	comment	How to store salt? @SilverViper That's a bad idea. It gives an attacker the salt, allowing them to compute a rainbow table ahead of time, before overtly breaching your database. In such a situation, the attacker can log in immediately after the attack and you have no time to react. See my answer for a more detailed explanation of this problem.
Jul 20	comment	How to store salt? @X-Zero There should be no difference at all, and it makes things more awkward when using an adaptive KDF.
Jul 20	comment	How to store salt? @Wes Hehe, thanks! :D
Jul 20	comment	How to store salt? At this point your answer hasn't really bought anything to the table, so you should probably have just linked the article in a comment. It's a nice article though - very thorough and covers all the bases. I'll keep a bookmark for future reference!
Jul 20	comment	How to store salt? @Earlz The second salt is called a pepper, which protects you from attackers that only have access to the database. It's useful, but since you're using parameterised queries (you are using them, right?) SQL injection isn't a problem, so that model of attacker is much less likely.
Jul 20	comment	Should I encrypt data on my server as an extra layer of protection? @Ramhound An interesting question indeed. I did ponder that, but assumed some sort of cross-payment service. Still, it's a bad idea.
Jul 20	comment	How wep wireless security works? Agreed. WEP is deprecated by the IEEE, which means that your ISP is basically going against what the IEEE says you should do. Furthermore, it can leave them in an interesting legal position should your network connection be used for illegal purposes, since they prevented you from securing your network to a reasonable level.
Jul 20	comment	How wep wireless security works? @Ramhound My bad, I missed that part of his question.
Jul 20	comment	How to store salt? @Earlz That's not the purpose of a salt, and it's nearly impossible to keep salts hidden anyway!