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SHA-3 hash generator

Generate SHA-3 digests (224, 256, 384 or 512 bits) in your browser. SHA-3 is built on the Keccak sponge construction, structurally different from SHA-2.

Input

Pick a variant, then generate. NIST SHA-3 padding (not raw Keccak).

The crypto library loads from a CDN on first use, then everything runs locally. Nothing you type is uploaded.
SHA-3 digest

The digest appears below in hexadecimal.

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Keccak sponge construction

SHA-3 is based on Keccak, the winner of NIST's 2007-2012 hash competition, standardized in FIPS 202. Instead of the Merkle-Damgard structure used by SHA-2, it uses a sponge construction that absorbs input into a 1600-bit state and squeezes out the digest. This completely different design means any future break of SHA-2 is unlikely to affect SHA-3.

SHA-3 vs Keccak

Raw Keccak (as used by Ethereum) and NIST SHA-3 differ in padding: SHA-3 appends the domain-separation bits 01 before the final pad. This tool computes standard NIST SHA-3, so its SHA3-256 of an input will not match Ethereum's Keccak-256 of the same input. Pick the variant that matches your protocol.

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SHA-3 Hash FAQs

Which SHA-3 variant should I choose?
SHA3-256 is the standard default, matching SHA-256's digest length with a different design. SHA3-512 gives the largest margin; SHA3-224 and SHA3-384 exist for protocols that need those exact sizes.
Is SHA-3 better than SHA-2?
Not better, different. SHA-3 was standardized as a backup in case SHA-2 ever weakens. Both are secure today; SHA-3's sponge design also makes it naturally resistant to length-extension attacks.
Why does my hash differ from Ethereum's Keccak-256?
Ethereum uses the original Keccak submission padding, while NIST SHA-3 added domain-separation bits. Same sponge, different padding, different digests. This tool follows the NIST standard.
How does the sponge construction work?
Input is absorbed into a large internal state in blocks, mixed with a permutation, then the digest is squeezed out of the state. The capacity parameter controls the security level.
Is my input uploaded?
No. SHA-3 is computed by the js-sha3 library loaded from a CDN and executed locally; your text never leaves the browser.
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