These functions are intended to work with » mhash. Mhash can be used to create checksums, message digests, message authentication codes, and more.
This is an interface to the mhash library. mhash supports a wide variety of hash algorithms such as MD5, SHA1, GOST, and many others. For a complete list of supported hashes, refer to the documentation of mhash. The general rule is that you can access the hash algorithm from PHP with MHASH_HASHNAME. For example, to access TIGER you use the PHP constant MHASH_TIGER.
This extension is obsoleted by Hash.