SHA3-512 is the largest SHA-3 digest (FIPS 202, 2015): 512 bits, 128 hex characters, from a Keccak sponge with a 1024-bit capacity, giving 256-bit collision resistance. It is the SHA-3 counterpart to SHA-512.

How does the sponge construction work?

SHA-3 is a sponge. A 1600-bit state absorbs the input a block at a time, running the Keccak-f permutation (24 rounds) after each block, then squeezes the digest out of the first part of the state. The part never exposed, the capacity, is twice the digest length, which is what sets the security level. The state is never fully output, so there is no length-extension attack, unlike SHA-2.

Is SHA3-512 secure, and how fast is it?

Yes, with the largest margin in the family and no known attack. It is also the slowest: with 1024 bits of capacity only 72 bytes are absorbed per permutation, so in software it runs around a third the speed of SHA-512. Pick it for 256-bit security requirements or long-term archives.

How does SHA-3 differ from Keccak?

Only in the padding. NIST appended two bits to the message before the Keccak padding when it standardised SHA-3 in 2015, so SHA-3 digests differ from the original Keccak's for every input. Ethereum adopted Keccak-256 before the change and kept it, so what Solidity calls sha3 or keccak256 does not match SHA3-256. This tool gives you both families; pick the one the other side uses.

Is my text or file uploaded anywhere?

Nothing leaves your browser. The hash is computed on your machine, by the browser's Web Crypto API or a WebAssembly build of the algorithm loaded on first use, and the page makes no request with your input. You can load the page, go offline and keep hashing.

How do I get the SHA3-512 of a file?

Drop the file onto the input or choose it with the button, and the tool reads it in your browser and hashes the bytes. Files up to 1 GB work; past that the browser would need the whole file in memory, so the tool declines. Paste the published digest into the Verify field to compare.

Hex, Base64 or Base64url: which should I use?

Hex is the common form: 128 characters from 0 to 9 and a to f, the same value in upper or lower case. Base64 writes the same 64 bytes in fewer characters, and Base64url swaps + and / for - and _ with no padding. Switch the output and the digest is re-encoded, not recomputed.

Why does my digest differ from the command line?

Text is hashed as UTF-8 bytes, which is what every language and command line does by default. A trailing newline changes the digest, so `echo -n` or this tool's input, with no newline added, matches a command-line tool run on a file without one.

How do I compute an HMAC-SHA3-512?

Turn on HMAC and enter the secret: the tool computes HMAC-SHA3-512 over the input with that key, the standard RFC 2104 construction, so the value matches what a server-side HMAC library produces. The key is hashed as UTF-8 text.

SHA3-512 hash generator.

Paste text or drop a file and read its SHA3-512 digest as you type. SHA3-512 is the largest SHA-3 digest, 256-bit security from the Keccak sponge; everything runs in your browser and nothing is uploaded.512 bits128 hex characters2015 published0 bytes uploaded

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How it works

4 steps, no account. It runs in your browser and nothing is uploaded.

Enter text or a file
Type or paste anything, or drop a file onto the input. The digest updates with every keystroke.
Pick the algorithm and format
SHA3-512 is the default; switch to SHA3-224, SHA3-256 and SHA3-384, and read the digest as hex or Base64.
Key it, when you need a signature
Turn on HMAC and enter a secret to sign the input instead of hashing it.
Verify, copy or download
Paste a published digest to confirm a download, or copy and download your own.

SHA-3 against SHA-2 and Keccak

SHA-3 is the standard in reserve. A different construction from SHA-2, chosen so a break in one would not take both; slower in software, immune to length extension.

SHA3-224
224 bits, 56 hex characters. A capacity of 448 bits: the 112-bit security level in the SHA-3 family.
SHA3-256
256 bits, 64 hex characters. Capacity 512 bits, 128-bit security. The SHA-3 size to reach for by default.
SHA3-384
384 bits, 96 hex characters. Capacity 768 bits, 192-bit security. Rarer, for policies that ask for more than 128 bits.
SHA3-512
512 bits, 128 hex characters. Capacity 1024 bits, 256-bit security. The slowest per byte: the sponge absorbs only 72 at a time.
Keccak-256
256 bits. The same permutation as SHA3-256 with the pre-standard padding, so different digests. What Ethereum means by sha3.
SHA-256
256 bits, 2001. A Merkle–Damgård chain: open to length extension, so HMAC exists to close the hole. Everywhere, and fast.
SHA-512
512 bits, 2001. Also Merkle–Damgård, on 64-bit words. Faster than SHA3-512 in software by two or three times.
BLAKE3
256 bits, 2020. A tree hash: parallel, several times faster than SHA-3 in software, and also immune to length extension.

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SHA3-512 hash generator.