HS Crypto is a software library in C (supplied with full source code) which offers a programmer an API to several data encryption / decryption algorithms. Implemented methods include the use of 2 either pre-defined or dynamically generated translation tables, an XOR-based stream cipher method with random dynamic key, plus the library includes RFC1321 MD5 Message Digest Algorithm The table encryption is implemented via the use of two either pre-defined translation tables or any of the 2 or a combination of dynamically generated translation tables. Decryption is implemented in a similar way using reverse tables. The stream cipher method uses randomly generated key which must be known to both receiver and transmitter to encode each byte with a rotating byte of the key RFC1321 MD5 algorithm generates a 16 byte data signature which is unique to the input data. This may be used for data integrity checking or in digital signature applications.