SHA-3 Hash Generator

What this tool does

SHA-3 Hash Generator computes the FIPS 202 SHA-3 digests in all four standard sizes and the original Keccak variants used by Ethereum and Solidity. It hashes text, hex or Base64 bytes and streamed files, supports per-line batches and verifies results against expected values.

SHA-3 is the newest NIST hash standard, published as FIPS 202 in 2015 after a public competition won by the Keccak algorithm. Unlike SHA-1 and SHA-2, which share the Merkle–Damgård design, SHA-3 is built on a sponge construction, so a weakness found in SHA-2 would not carry over. It is not vulnerable to length-extension attacks, which makes it safe to use as a simple keyed hash, and it is increasingly required in new standards and post-quantum signature schemes.

This tool offers SHA3-224, SHA3-256, SHA3-384 and SHA3-512, plus Keccak-224 to Keccak-512, the pre-standard versions with the original padding byte. That distinction matters: Ethereum adopted Keccak before NIST changed the padding, so Solidity’s keccak256() and Ethereum addresses use Keccak-256, whose output differs from SHA3-256 for the same input. You can hash UTF-8 text, or raw bytes given as hex, which is how Ethereum data is usually written, as well as streamed files of any size. All hashing runs in your browser.

How to use SHA-3 Hash Generator

1. Select Text or Files as the input source.
2. Enter text, hex bytes or Base64 bytes, or drop files.
3. Choose the Algorithm: a SHA3 size, or a Keccak variant for Ethereum work.
4. Set “Input is” to Hex bytes when hashing encoded data such as an ABI-packed value.
5. Pick the Output format and, if needed, paste a value to compare against.
6. Copy the result or export a checksum file.

Tips for better results

• An Ethereum function selector is the first 4 bytes (8 hex characters) of the Keccak-256 of its signature, for example transfer(address,uint256) gives a9059cbb.
• Ethereum hex values often start with 0x; the hex input mode strips it automatically.
• SHA3-256 of an empty input is a7ffc6f8bf1ed76651c14756a061d662f580ff4de43b49fa82d80a4b80f8434a, which is useful to confirm you picked SHA-3 rather than Keccak.
• SHA-3 is slower than SHA-256 in software but resists length-extension attacks by design.

Common use cases

• Computing Solidity function selectors and event topics.
• Producing SHA3-256 digests required by a newer protocol or compliance standard.
• Cross-checking hashes produced by a blockchain library or smart contract.
• Verifying files distributed with SHA3 checksums.

Common mistakes to avoid

• Using SHA3-256 where Ethereum expects Keccak-256, or the reverse. The outputs never match.
• Hashing the text “0x1234” when the protocol expects the two bytes 12 34; set “Input is” to Hex bytes.
• Assuming SHA-3 replaces SHA-2 because SHA-2 is broken. SHA-2 remains secure; SHA-3 is an alternative with a different design.