blake2b256

blake2b256, also known as BLAKE2b-256, is the 256-bit digest variant of the BLAKE2b cryptographic hash function. BLAKE2b is designed for speed and security on 64-bit architectures and supports variable output lengths. BLAKE2b-256 is produced by configuring BLAKE2b to produce a 32-byte (256-bit) digest. The BLAKE2 family was designed by Jean-Philippe Aumasson, Samuel Neves, Zooko Wilcox-O'Hearn, and Christian Winnerlein.

The core of BLAKE2b uses a compression function with 12 rounds, operating on 1024-bit input blocks and maintaining an eight-word (64-bit) internal state. It supports keying for MAC-like use, as well as salt and personalization to domain-separate hash instances. It is designed to be faster than MD5 and SHA-1 on contemporary CPUs and often competitive with SHA-256, while offering a simpler implementation and robust security properties.

Security and usage: There are no practical attacks against BLAKE2b-256 that are known to undermine its general design as of now; its security follows from the BLAKE2b design and the chosen digest length. For a 32-byte (256-bit) digest, the expected security level is around 2^256 preimage resistance and about 2^128 collision resistance, assuming no cryptanalytic breakthroughs. It can be used as a drop-in replacement for SHA-256 in many contexts and is common for file integrity checks, digital signatures, and keyed hashing via HMAC-like modes.

Availability: Implementations exist in libraries such as OpenSSL, libsodium, and the reference BLAKE2 code, with broad support across programming languages. BLAKE2b-256 is favored on 64-bit systems for its speed and strong integrity guarantees.