About SHA3-256 Hash Generator
This SHA3-256 hash generator computes the SHA3-256 digest of your text or file. SHA3-256 produces a 256-bit value, written as 64 hexadecimal characters. It is free, needs no sign-up and runs in your browser, so nothing you enter is uploaded.
SHA-3 is a different design from SHA-1 and SHA-2. It is built on the Keccak sponge construction, which won a public NIST competition and was published as FIPS 202 in 2015. It was chosen as a backup in case SHA-2 were ever weakened, and it is not subject to the length-extension trick that affects plain SHA-256.
The most important thing to know is that SHA3-256 is not the same as Keccak-256. Ethereum and some older libraries use the original Keccak submission, which differs in its padding byte, so the digest of the same text is different. If your result does not match an Ethereum tool, that is the reason. This page computes standard FIPS 202 SHA3-256.
Browsers do not offer SHA-3 through Web Crypto, so this page uses its own implementation, checked against the NIST test vector for "abc". For ordinary integrity checks SHA-256 is more widely supported, and SHA3-256 is the right pick when a specification names it.
How to use SHA3-256 Hash Generator
- Choose an algorithm from the row of buttons: MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, SHA3-256, SHA3-512 or CRC32. SHA-256 is a good default.
- Choose Text and type or paste your input, or choose File and pick a file from your device. The hash updates as you type.
- Read the digest in the result box. Tick Uppercase for capital hex letters, or Base64 output to show the digest in Base64 instead of hex.
- For a keyed hash, tick HMAC with secret key and enter the key. The result is then labelled HMAC-SHA-256 (or whichever algorithm you chose).
- To verify a download or a value from documentation, paste the expected hash into Compare with a known hash. The tool says Match or No match.
- Use Copy to put the digest on your clipboard.
Features
- Nine algorithms: MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, SHA3-256, SHA3-512 and CRC32.
- Hashes text as UTF-8, so accented letters, other scripts and emoji hash the same way as on a server or in a command-line tool.
- Hashes a file you choose from your device. The file is read in your browser and never uploaded.
- HMAC with a secret key for every algorithm except CRC32, following RFC 2104.
- Hex output in lowercase or uppercase, or Base64 output.
- Compare with a known hash. Case, spaces and a leading 0x are ignored, and the expected value can be hex or Base64.
- SHA-1, SHA-256, SHA-384 and SHA-512 use the Web Crypto API in your browser, which is fast and well tested.
- A warning appears when you pick MD5, SHA-1 or CRC32, because they are not safe for security purposes.
- One-click copy of the result.
Worked examples
SHA3-256 of "abc" gives 3a985da74fe225b2045c172d6bd390bd855f086e3e9d525b46bfe24511431532
The NIST test vector.
SHA3-256 of an empty input gives a7ffc6f8bf1ed76651c14756a061d662f580ff4de43b49fa82d80a4b80f8434a
SHA3-256 of "The quick brown fox jumps over the lazy dog" gives 69070dda01975c8c120c3aada1b282394e7f032fa9cf32f4cb2259a0897dfc04
Privacy: how it works
- The text, the file and the HMAC key stay in your browser tab. Nothing is sent to Ulkaa or to any other server, which you can confirm in the Network tab of your browser developer tools.
- Because the work happens on your own device, large files are limited by your browser memory rather than by an upload limit.
Tips
- To verify a download, choose File, pick the downloaded file, and paste the publisher hash into the compare box. A match means the bytes are identical to what the publisher hashed.
- Hash the same text twice with a trailing space added once. Seeing two unrelated digests is the quickest way to understand the avalanche effect.
- A hash you found on the same page as the download only protects against corruption. It cannot protect you if the page itself was altered.
- HMAC takes the key as plain text. If your key is hex or Base64, decode it first, or the result will not match another system.
Frequently asked questions
Is it really free?
Yes. There is no price, no trial and no credit card. Ulkaa Tool does the work with your own device, so there is no server bill to pass on to you.
Do I need an account?
No. There is no sign-up and no login. Open the page and use it. An Ulkaa account is not needed for anything on this tool.
Does it run in my browser?
Yes. Your text and files are processed by code running in your browser tab, on your own device.
Is my data uploaded?
No. Your text and files are never sent to Ulkaa or to anyone else. You can check this yourself by watching the Network tab in your browser developer tools while you use the tool.
Is SHA3-256 the same as Keccak-256?
No. They share the same core, but SHA3-256 adds a different padding byte, so the digests differ. Ethereum uses Keccak-256. This tool computes the standard SHA3-256.
Is SHA-3 better than SHA-2?
It is not stronger in any proven sense. It is a different design, so a break in SHA-2 would not carry over. It resists length extension by construction. Both are considered secure today.
More Hash Generator pages
- Hash GeneratorHash text or a file with MD5, SHA-1, SHA-2, SHA-3 or CRC32, add an HMAC key, and check the result against a known hash.
- MD5 Hash GeneratorGet the 128-bit MD5 hash of text or a file as 32 hexadecimal characters.
- SHA-1 Hash GeneratorGet the 160-bit SHA-1 hash of text or a file as 40 hexadecimal characters.
- SHA-224 Hash GeneratorGet the 224-bit SHA-224 hash of text or a file as 56 hexadecimal characters.
- SHA-256 Hash GeneratorGet the 256-bit SHA-256 hash of text or a file as 64 hexadecimal characters.
- SHA-384 Hash GeneratorGet the 384-bit SHA-384 hash of text or a file as 96 hexadecimal characters.
- SHA-512 Hash GeneratorGet the 512-bit SHA-512 hash of text or a file as 128 hexadecimal characters.
- SHA3-512 Hash GeneratorGet the 512-bit SHA3-512 hash of text or a file as 128 hexadecimal characters.
- CRC32 Checksum CalculatorCalculate the 32-bit CRC32 checksum of text or a file as 8 hexadecimal characters.
- HMAC-SHA256 GeneratorSign a message with a secret key using HMAC-SHA256 and read the result as hex or Base64.
- File Checksum CalculatorHash a file on your device and compare it with the checksum the publisher gave you.