SHA-512 is a cryptographic hash function that produces a fixed-size 512-bit (64-byte) hash value from input data of any size. It is part of the SHA-2 family, designed by the National Security Agency (NSA) and widely used for data integrity and security purposes. The output is typically represented as a 128-character hexadecimal number. This hash function is commonly used in various applications, including digital signatures, password hashing, and data verification. Its strength lies in its resistance to collision attacks, making it difficult for two different inputs to produce the same hash output, thus ensuring data authenticity.