Blake2b-256 Hash

What is Blake2b-256?

Blake2b-256 is a cryptographic hash function designed as part of the BLAKE (Blake2) family, introduced in 2013 by Jean-Philippe Aumasson, Daniel J. Bernstein, and Zuccherato as an evolution of the original BLAKE (Blake1) to address security vulnerabilities and improve performance. Structurally, it follows a Merkle-Damgård construction with a fixed output length of 256 bits, leveraging a variable-length input (up to 2³⁶⁵–¹ bytes) processed through a compression function composed of 16 rounds of permutation operations on 128-bit words. The algorithm incorporates a keyed variant (Blake2b-keyed) and supports parallelizable compression blocks, making it highly efficient for both general-purpose hashing and cryptographic applications like password storage (via keyed hashing) and blockchain data integrity verification. Its design prioritizes speed, simplicity, and resistance to length-extension attacks, while maintaining compatibility with the broader BLAKE family’s optimizations for modern hardware, including SIMD instructions and GPU acceleration.

Blake2b-256’s susceptibility to cracking stems from several architectural and implementation weaknesses. Unlike modern keyed hashes (e.g., Argon2), it lacks built-in salting by default, making it vulnerable to precomputed rainbow table attacks if reused across contexts. Its compression rounds, though robust against brute-force efforts, are optimized for speed rather than collision resistance, enabling GPU/FPGA-based attacks (e.g., via CUDA or OpenCL) to achieve high throughput for hash inversion or collision finding. Additionally, its fixed-output length and lack of a post-processing step (like HMAC) expose it to length-extension attacks if improperly chained, and its reliance on 128-bit internal state words may be exploitable via differential cryptanalysis under specialized hardware acceleration. While not inherently broken, these factors render it less suitable for high-security applications compared to dedicated keyed hashes or memory-hard functions.

Identifying Blake2b-256 Hashes

Identifying a hash blindly is often difficult because multiple algorithms can output strings of the exact same length. For example, a standard 32-character hexadecimal string could be MD5, NTLM, MD4, or LM. To definitively identify Blake2b-256, security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

How to Crack Blake2b-256

If you need to recover the plaintext password for a Blake2b-256 hash during a penetration test or forensics investigation, you must supply the correct module ID to your cracking software. Use the exact commands provided at the top of this page to target the hash successfully.