Package eu.webtoolkit.jwt.auth

Class HashFunction

java.lang.Object
eu.webtoolkit.jwt.auth.HashFunction
Direct Known Subclasses:
BCryptHashFunction, MD5HashFunction
public abstract class HashFunction extends Object
An abstract cryptographic hash function interface.

A cryptographic hash function computes a hash value from a message, for which it is hard to guess another message that generates the same hash.

These hash functions are intended for short messages, typically passwords or random tokens, and thus not suitable for computing the hash value of a large document.

When used for passwords, to avoid dictionary attacks, the hash functions accept also a random salt which is hashed together with the password. Not all hash functions are adequate for passwords hashes.

  • Constructor Details

    • HashFunction

      public HashFunction()

  • Method Details

    • getName

      public abstract String getName()
      Returns the name for this hash function.

      This should return a (short) name that uniquely identifies this hash function.

    • compute

      public abstract String compute(String msg, String salt)
      Computes the hash of a message + salt.

      The message is usually an ASCII or UTF-8 string.

      The salt and the computed hash are encoded in printable characters. This is usually ASCII-encoded or could be Base64-encoded.

    • verify

      public boolean verify(String msg, String salt, String hash)
      Verifies a message with the salted hash.

      The base implementation will recompute the hash of the message with the given salt, and compare it to the hash.

      Some methods however store the salt and additional settings in the hash, and this information is thus needed to verify the message hash.