Wikipedia lists it in his article in the section 'Radix-64 Applications ' and is the origin of it at crypt (3) with apparently onlyement modern use being bcrypt. This format is particularly useful for storing hashes of passwords, since all parameters except the actual password are included.įirst of all, what is strange is that the encoding used for salt and hash is a strange non-standard Base64 dialect. VSThis measure protects against rainbow tables, that is, by using a list of precomputed hashes of commonly used passwords.Īnd finally the last 23 bytes or 31 encoded ASCII characters are the real bcrypt hash: HaK3MyTDt / W 8FCjUOtbY3Pmres5rsma. Most implementations automatically create a salt for the caller, which is fine. The next 22 ASCII characters (16 raw bytes) 0SN / h83Gt1jZMR6924.Kd. Next part 08 $ is the work factor passed to the function. Historically, bcrypt was $ 2 $ but since no one at the time thought about Unicode support, a new version had to be defined. first part $ 2a $ is the protocol version identifier. Here is the modular encryption format defined and used by OpenBSD. So, how it works You first need a password and set the number of iterations as a log work factor between 4 and 31, doubling the required calculation with each increment. This is called key extension and should be used with any what (usually weak) password provided by the user to protect against brute force attacks (i.e. Compared to cryptographic hash functions (like SHA-256), the main advantage of using bcrypt is that a developer can set the cost of computing the hash. The Bcrypt protocol… is a kind of mess Originally posted by Patrick Favre -Bubble theīy writing my own library bcrypt, being dissatisfied with the current implementation of the de facto Java standard jBcrypt, I discovered a lot of strange things around the bcrypt protocol (note: not the underlying cryptographic primitive 'Eksblowfish ').ī crypt is a password hash function designed by Niels Provos and David Mazières in 1999 which became popular as the default password hash algorithm for OpenBSD ¹.

What is bcrypt