About the SHA-3 Hash Generator
SHA-3, standardised by NIST in 2015, uses the Keccak sponge construction, a completely different design from SHA-1 and SHA-2. That makes it a valuable alternative: if a weakness were ever found in the SHA-2 family, SHA-3 would be unaffected. This tool offers all four output sizes and computes them locally from your text.
SHA-3 is immune to the length-extension attacks that affect SHA-256 and SHA-512, which simplifies some protocols. It is secure and, like the other general-purpose hashes, fast, so not for passwords. Note that SHA-3 differs from plain Keccak-256, which is used by Ethereum; that variant is available in the Keccak-256 tool.
The sponge works by absorbing message blocks into a 1600-bit state and then squeezing output back out of it, and the size you pick changes the rate at which it absorbs. So SHA3-256 and SHA3-512 are not related to each other by truncation the way SHA-256 and SHA-224 are: they read the input at different block sizes, which changes both the digest and the throughput. Larger sizes take in fewer bytes per permutation and therefore run measurably slower on the same input. Choose the bit size to match what the receiving system expects, and hex or Base64 output.
How to use
- Paste text.
- Choose the SHA-3 size.
- Copy the hash.
Common questions
- Is SHA-3 better than SHA-256?
- Not stronger in practice, but built on a different design, so it is a hedge against a future SHA-2 weakness. It also resists length-extension attacks.
- Is SHA-3 the same as Keccak-256?
- No. SHA-3-256 uses different padding from the original Keccak-256 that Ethereum uses. Use the Keccak-256 tool for Ethereum.
- Which size should I pick?
- SHA3-256 is the common default; match the size the other system specifies.