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Keccak-512 Hash Generator

Generate Keccak-512 hashes online. The original pre-NIST Keccak, 512-bit (128 hex character) output. Note: Keccak-512 differs from SHA3-512. Supports HMAC-Keccak-512.

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Frequently Asked Questions

What is Keccak-512?
Keccak-512 is the largest output variant of the original Keccak hash function, producing a 512-bit (128 hex character) digest. It uses 0x01 padding, unlike SHA3-512 (0x06 padding).
Keccak-512 vs SHA3-512 — what's the difference?
Padding only: 0x01 for Keccak-512, 0x06 for SHA3-512. They produce completely different digests for the same input.
How secure is Keccak-512?
Keccak-512 provides 256-bit collision resistance and 512-bit preimage resistance. The sponge construction makes it immune to length-extension attacks. No practical attacks are known.

About Keccak-512 Hash Generator

Keccak-512 is the 512-bit variant of the original Keccak hash function (pre-NIST standardization). It uses the Keccak sponge with a 576-bit rate and 1024-bit capacity — the same parameters as SHA3-512 — but applies 0x01 padding instead of NIST's 0x06. This produces a completely different 512-bit (128 hex character) digest from SHA3-512 for the same input.

Keccak-512 vs SHA3-512

The sole algorithmic difference is one byte of padding. Keccak-512 appends 0x01 before the multi-rate padding; SHA3-512 appends 0x06 (encoding NIST's 2-bit domain suffix "01"). Despite this minor difference, the outputs are completely unrelated. Always use the variant that matches your system's specification.

Use Cases

Keccak-512 is used in legacy systems built before the NIST SHA-3 standard was finalized, or in systems that require explicit compatibility with the original Keccak competition submission. For new applications, SHA3-512 (the NIST standard) is generally preferred.