Javascript implementation of some secure hash algorithms:
* md5 message digest algorithm (rfc 1321)
* ripemd-160 algorithm
* sha-1 secure hash algorithm (fips 180-1)
* sha-256 secure hash algorithm (fips 180-2)
* sha-512 secure hash algorithm (fips 180-2)
* hmac keyed-hashing for message authentication (rfc 2104)