In your case, breaking the hash algorithm is equivalent to finding a collision in the hash algorithm. That means you don’t need to find the password itself (which would be a preimage attack), you just need to find an output of the hash function that is equal to the hash of a valid password (thus … Read more
Short answer: No, time() is not a good salt. Long answer: copied from my answer to Salt Generation and open source software What is a salt? A salt is a random set of bytes of a fixed length that is added to the input of a hash algorithm. Why is salting (or seeding) a hash … Read more
It’s been a while since I asked this question, and I’m much more familiar with the cryptographic theory now, so here is the more modern approach: Reasoning Don’t use md5. Don’t use a single cycle of sha-family quick hashes. Quick hashes help attackers, so you don’t want that. Use a resource-intensive hash, like bcrypt, instead. … Read more
Maybe because salt goes well with hash?
has_secure_password uses bcrypt-ruby. bcrypt-ruby automatically handles the storage and generation of salts for you. A typical hash from bcrypt-ruby looks like this: $2a$10$4wXszTTd7ass8j5ZLpK/7.ywXXgDh7XPNmzfIWeZC1dMGpFghd92e. This hash is split internally using the following function: def split_hash(h) _, v, c, mash = h.split(‘$’) return v, c.to_i, h[0, 29].to_str, mash[-31, 31].to_str end For the example hash this function yields: … Read more
With “salt round” they actually mean the cost factor. The cost factor controls how much time is needed to calculate a single BCrypt hash. The higher the cost factor, the more hashing rounds are done. Increasing the cost factor by 1 doubles the necessary time. The more time is necessary, the more difficult is brute-forcing. … Read more
Since questions about salting hashes come along on a quite regular basis and there seems to be quite some confusion about the subject, I extended this answer. What is a salt? A salt is a random set of bytes of a fixed length that is added to the input of a hash algorithm. Why is … Read more
It doesn’t stop dictionary attacks. What it does is stop someone who manages to get a copy of your password file from using a rainbow table to figure out what the passwords are from the hashes. Eventually, it can be brute-forced, though. The answer to that part is to force your users to not use … Read more
Based on the other answers to this question, I’ve implemented a new approach using bcrypt. Why use bcrypt If I understand correctly, the argument to use bcrypt over SHA512 is that bcrypt is designed to be slow. bcrypt also has an option to adjust how slow you want it to be when generating the hashed … Read more
Using password_hash is the recommended way to store passwords. Don’t separate them to DB and files. Let’s say we have the following input: $password = $_POST[‘password’]; You first hash the password by doing this: $hashed_password = password_hash($password, PASSWORD_DEFAULT); Then see the output: var_dump($hashed_password); As you can see it’s hashed. (I assume you did those steps). … Read more