SM3 is China's national cryptographic hash, published by the Office of State Commercial Cryptography Administration in 2010 and standardised as GB/T 32905-2016 and, since 2018, in ISO/IEC 10118-3. It is a 256-bit Merkle–Damgård hash in SHA-256's shape, with its own message expansion and round functions.

Yes, with no practical attack on the full 64 rounds (published results reach about a third of them). It gives 128-bit collision resistance, the same as SHA-256, and performs about the same in software. It has had less open cryptanalysis than SHA-2, which is the usual caveat.

Everywhere Chinese regulation applies: SM2 digital signatures hash with SM3, the TLCP transport protocol and the SM-cipher TLS 1.3 suites use it, Chinese banking, government and payment systems require it, and OpenSSL, BouncyCastle and the Linux kernel implement it for that reason.

How does SM3 compare to SHA-256?

Same size, same construction family, same security level, different constants and round functions, so unrelated digests. A system wants one or the other by policy: SM3 with SM2 and SM4 in China, SHA-256 almost everywhere else. The toolbar gives you SHA-256 and SHA3-256 beside it to compare.

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 SM3 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: 64 characters from 0 to 9 and a to f, the same value in upper or lower case. Base64 writes the same 32 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-SM3?

Turn on HMAC and enter the secret: the tool computes HMAC-SM3 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.

SM3 hash generator.

Paste text or drop a file and read its SM3 digest as you type. SM3 is China's national 256-bit hash, required with SM2 and SM4 in Chinese systems and in ISO/IEC 10118-3; everything runs in your browser and nothing is uploaded.256 bits64 hex characters2010 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
SM3 is the default; switch to SHA-256 and SHA3-256, 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.

Standards side by side

Standards travel with their jurisdictions. The same bytes, four standardised digests: which one a system wants depends on who wrote its rules.

SM3
China's GB/T 32905-2016, also ISO/IEC 10118-3:2018. 256 bits, Merkle–Damgård, a design in SHA-256's shape. Required with SM2 and SM4 in Chinese systems.
Whirlpool
ISO/IEC 10118-3:2004. 512 bits from an AES-like block cipher run in Miyaguchi–Preneel mode. VeraCrypt and TrueCrypt offered it.
SHA-256
NIST FIPS 180-4. 256 bits. The world's default: TLS, code signing, Bitcoin, every package manager.
SHA3-256
NIST FIPS 202. 256 bits from the Keccak sponge, the backup design chosen in case SHA-2 falls.

Nearby in the hash generators. Every one free, in the browser.

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Lets your AI editor search, preview and install blocks for you.MCP server: Basic usage
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SM3 hash generator.