yescrypt Hash

What is yescrypt?

YesCrypt is a cryptographic hash function designed as an evolutionary extension of the scrypt memory-hard key derivation function (KDF), specifically tailored for password hashing in modern cryptographic applications. Introduced in 2013 as part of the YesCrypt project, it builds upon scrypt’s core principles—namely, its resistance to brute-force and GPU/ASIC attacks through memory-intensive operations—while introducing architectural refinements to mitigate emerging threats. Structurally, YesCrypt retains scrypt’s hierarchical design, incorporating a salted input, a variable-cost parameterized memory pool (S), and a parallelizable but memory-bound CPU-bound operation (ROM) to enforce computational overhead. The primary use-case lies in secure password storage, where its memory-hard properties deter large-scale cracking via distributed or specialized hardware, though it is not natively standardized and remains niche compared to alternatives like Argon2 or bcrypt. Its modularity allows customization of memory usage (B), CPU cost (N), and parallelization (p), enabling fine-grained trade-offs between security and performance for specific deployment scenarios.

Despite its robust design, YesCrypt exhibits vulnerabilities rooted in its reliance on tunable parameters and implementation quirks. The algorithm’s memory-hard nature is theoretically sound, but its susceptibility to cracking stems from suboptimal parameter defaults and GPU/CPU optimizations. Early versions lacked rigorous validation of salt distribution, leaving systems vulnerable to rainbow table attacks if salts were reused or predictable. Moreover, YesCrypt’s parallelizable ROM function, while mitigating GPU advantages, can be optimized on modern CPUs with techniques like cache exploitation or side-channel attacks, reducing its intended computational overhead. Additionally, its reliance on legacy cryptographic assumptions (e.g., SHA-256 for intermediate hashing) introduces collision risks if underlying primitives are compromised. Finally, the absence of formal post-quantum resistance or adaptive parameter updates renders it vulnerable to future advancements in cryptanalysis, particularly against quantum-resistant attacks or specialized hardware accelerators.

Identifying yescrypt 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 yescrypt, security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

How to Crack yescrypt

If you need to recover the plaintext password for a yescrypt 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.