SHA SHA (Secure Hash Algoritm) is a widely used hashing algorithm used to generate signatures for data packet authentication. Hashing is a process of producing numeric values to strings of text. The SHA algorithm produces a 160-bit hash value from an arbitrary length string. It uses a longer key than MD5 and should thus be more secure, however it is a fairly new algorithm and has not been tested as extensively.
Using SHA to produce a digital signature for packet authentication accomplishes two important functions:
It proves the data was sent by the sender and was not forged (data authentication).
It proves that the message was not modified or tampered with (data integrity).
