SHA-3 Generator

Generate SHA3-224, SHA3-256, SHA3-384 or SHA3-512 hashes. The FIPS 202 standard, built on Keccak.

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What is SHA-3?

A different design, kept ready in case SHA-2 falls.

SHA-3 is the hash family NIST standardised in 2015 as FIPS 202, after a public competition won by Keccak. Instead of SHA-2's Merkle–Damgård design it uses a sponge construction, so an attack on SHA-2 wouldn't carry over. It comes in the same four sizes as SHA-2: 224, 256, 384 and 512 bits.

SHA-3 is not the Keccak-256 hash that Ethereum uses. NIST changed the padding when it standardised Keccak, so the same input gives a different result. Like any fast hash, it isn't for storing passwords either.

Frequently asked

Is SHA-3 better than SHA-256?

Not more secure in practice: both are unbroken. SHA-3 uses a completely different design, the sponge construction, so it's a backup if SHA-2 is ever broken, and it resists length-extension attacks. SHA-256 is faster in most software and far more widely supported.

Is SHA3-256 the same as Keccak-256?

No. Ethereum and Solidity's keccak256 use the original Keccak submission. NIST changed the padding when it published SHA-3, so the same input gives a different hash. This tool computes the FIPS 202 version.

Which SHA-3 size should I pick?

SHA3-256 is the usual default. Otherwise use whatever your protocol specifies: SHA3-224 and SHA3-384 exist mainly to match the SHA-2 output sizes.