Crypto Tools
SHA-512 Hash
Hash a string with SHA-512, with optional HMAC key authentication. Computed locally, nothing is uploaded.
HMAC is a message authentication code built on a hash function and a secret key. It verifies that data is intact and really comes from who it claims to. Published as RFC 2104 in 1997, it is used widely in IPSec, TLS/SSL and similar protocols.
About SHA-512
SHA-512 is one of the longest-output members of the SHA-2 family, designed by the U.S. National Security Agency (NSA) and published by NIST in 2001. It turns data of any length into a 512-bit (64-byte) digest, usually written as 128 hexadecimal characters.
On 64-bit processors SHA-512 is usually faster than SHA-256, because it works on 64-bit words internally. It fits the scenarios with the highest security requirements: digital signatures, certificate authority (CA) signatures, high-assurance file integrity checks. No practical collision attack against SHA-512 is known.
About HMAC
HMAC (Hash-based Message Authentication Code) adds a shared secret key on top of the hash function, so only parties holding the key can compute and verify the code. That is what keeps a message from being altered or forged along the way. HMAC-SHA512 gives a longer digest than HMAC-SHA256, for cases that ask for a longer authentication code.
The SHA family compared
The SHA family covers SHA-1 (160 bit, no longer recommended), SHA-224/256 (224/256 bit, known as SHA-2), SHA-384/512 (384/512 bit, also SHA-2) and the newer SHA-3 series. SHA-512 gives the longest output and performs well on 64-bit systems, which makes it the first pick where the strongest guarantee is needed.