Initializes a new instance of the HMACSHA1 class with a randomly generated key.
Assembly: mscorlib (in mscorlib.dll)
HMACSHA1 is a type of keyed hash algorithm that is constructed from the SHA1 hash function and used as an HMAC, or hash-based message authentication code. The HMAC process mixes a secret key with the message data, hashes the result with the hash function, mixes that hash value with the secret key again, and then applies the hash function a second time. The output hash is 160 bits (20 bytes) in length.
This constructor uses a 64-byte, randomly generated key.