KMAC256 Hash Generator
Generate KMAC256 hashes online. Keccak MAC with 256-bit security, built on cSHAKE256. NIST SP 800-185. Configure key, output bit length, and customization string for domain separation.
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About KMAC256 Hash Generator
KMAC256 is the 256-bit security variant of KMAC (Keccak Message Authentication Code), standardized in NIST SP 800-185. It is built on cSHAKE256 using N='KMAC', providing a keyed hash function with 256-bit collision resistance. KMAC256 supports variable output length, making it suitable for MACs, key derivation, and PRF applications requiring the highest security margin.
Post-Quantum Considerations
KMAC256 provides 256-bit classical security. Against quantum adversaries using Grover's algorithm, the effective security is approximately 128 bits for key search. For post-quantum resilience with a 128-bit quantum security level, KMAC256 with a 256-bit key is recommended over KMAC128.
Variable Output Length Applications
KMAC256's variable output is particularly useful for deriving multiple keys of different lengths from a single master key (e.g., 128-bit AES key, 256-bit HMAC key) by varying the context or output length parameter, all from a single KMAC256 computation per context.