What is Blake2b?

BLAKE2b is a high-speed cryptographic hash function that serves as the successor to the original BLAKE algorithm, which was a finalist in the NIST SHA-3 competition. Designed by Jean-Philippe Aumasson, Samuel Neves, Zooko Wilcox-O'Hearn, and Christian Winnerlein, BLAKE2b is optimized for 64-bit platforms and can produce digests of up to 512 bits. It is based on a modified ChaCha stream cipher core combined with a HAIFA iteration mode, processing input data in 128-byte blocks through 12 rounds of mixing operations that blend message words with internal state using addition, XOR, and rotation operations.

BLAKE2b is renowned for being faster than MD5 while providing security comparable to SHA-3. It requires no special hardware instructions and performs exceptionally well on modern 64-bit processors, making it one of the fastest secure hash functions available in software. The algorithm supports keyed hashing (MAC), personalization, and tree hashing modes natively without requiring additional constructions like HMAC. BLAKE2b has been formally analyzed and has no known security weaknesses; its large security margins inherited from the BLAKE SHA-3 submission provide confidence in its long-term resilience against cryptanalytic advances.

In the cryptocurrency world, BLAKE2b is most notably used by Siacoin as its proof-of-work mining algorithm, where it enables efficient mining while maintaining cryptographic integrity. Nano (formerly RaiBlocks) also uses BLAKE2b for its block hashing operations. Beyond cryptocurrencies, BLAKE2b has achieved widespread adoption across the software industry — it is the default hash function in libsodium, used by Argon2 (the Password Hashing Competition winner) as an internal component, integrated into WireGuard VPN, and supported natively in Linux kernel 4.12+. Its combination of speed, security, and simplicity has made it one of the most widely deployed modern hash functions.