SHA3-256 Generator
Compute the SHA3-256 hash of any text with the Keccak-based SHA-3 standard from FIPS 202. The tool encodes your input as UTF-8 and returns the 256-bit digest as 64 hex characters or as Base64. It is useful for developers who need SHA-3 digests for protocols, test fixtures and integrity checks, or who want to compare results with another SHA-3 library.
Frequently asked questions
What is SHA3-256?
SHA3-256 is a hash function from the SHA-3 standard, FIPS 202, built on the Keccak sponge construction. It produces a 256-bit digest, shown as 64 hexadecimal characters. Its internal design is completely different from SHA-2.
Is SHA3-256 the same as Keccak-256 used by Ethereum?
No. Ethereum uses the original Keccak-256 submission, which pads its input differently from the final SHA-3 standard. The two give different digests for the same text. This tool computes the standardized SHA3-256 from FIPS 202.
What are the SHA3-256 test vectors?
The empty string hashes to a7ffc6f8bf1ed76651c14756a061d662f580ff4de43b49fa82d80a4b80f8434a. The text abc hashes to 3a985da74fe225b2045c172d6bd390bd855f086e3e9d525b46bfe24511431532. Both match the NIST examples.
Why choose SHA-3 over SHA-256?
SHA-3 offers a backup if a weakness is ever found in SHA-2, because the two designs share nothing. It is also immune to length extension attacks. SHA-256 remains secure and is more widely supported, so pick SHA-3 when a specification calls for it.
How is my input processed?
Your text is encoded as UTF-8 and hashed byte for byte. Every space and line break counts. The computation runs in WebAssembly on the server, and the input is not stored.
What is the difference between the hex and Base64 outputs?
Both encode the same 32-byte digest. Hex uses 64 lowercase characters, while Base64 needs 44 characters including one padding sign. Use the format your code or documentation expects.
Can SHA3-256 be reversed?
No. SHA3-256 is a one-way function, so the original text cannot be computed from the digest. Short or common inputs can still be guessed by trying candidates, so never treat a hash of a guessable value as secret.
Is SHA3-256 suitable for passwords?
Not on its own. It is fast, so attackers can test many guesses per second. Use a password hashing function such as Argon2, bcrypt or scrypt instead.
How long may the text be?
The tool accepts up to 5 MiB of text per request. Longer data or binary files are better hashed locally, for example with openssl dgst -sha3-256.
Does SHA3-256 give the same result everywhere?
Yes. Any correct implementation returns the same digest for the same bytes. If two tools disagree, the cause is almost always a different text encoding, a trailing newline or the Keccak variant mix-up described above.