this.description="The SHA-2 (Secure Hash Algorithm 2) hash functions were designed by the NSA. SHA-2 includes significant changes from its predecessor, SHA-1. The SHA-2 family consists of hash functions with digests (hash values) that are 224, 256, 384 or 512 bits: SHA224, SHA256, SHA384, SHA512.<br><br><ul><li>SHA-512 operates on 64-bit words.</li><li>SHA-256 operates on 32-bit words.</li><li>SHA-384 is largely identical to SHA-512 but is truncated to 384 bytes.</li><li>SHA-224 is largely identical to SHA-256 but is truncated to 224 bytes.</li><li>SHA-512/224 and SHA-512/256 are truncated versions of SHA-512, but the initial values are generated using the method described in Federal Information Processing Standards (FIPS) PUB 180-4.</li></ul> The message digest algorithm for SHA256 variants consists, by default, of 64 rounds, and for SHA512 variants, it is, by default, 160.";