mhash() applies a hash function specified by
hash
to the data
.
hash
The hash id. One of the MHASH_XXX constants.
data
The user input, as a string.
key
If specified, the function will return the resulting HMAC instead. HMAC is keyed hashing for message authentication, or simply a message digest that depends on the specified key. Not all algorithms supported in mhash can be used in HMAC mode.