SHA3-256 Hash Generator

What the SHA3-256 generator does

This produces the SHA3-256 hash of your text, a 64-character hex fingerprint. Type or paste your text, press Convert, and copy or download the result. SHA3-256 is the most-used member of the SHA-3 family, and like any hash it is a one-way fingerprint, so the same text always gives the same result and there is no turning the result back into your text.

It runs in your browser, so nothing you enter is uploaded.

How to use it

1. Enter your text. Type or paste it, or upload a plain text file.
2. Press Convert. The 64-character SHA3-256 hash appears, ready to Copy or Download.

A completely different kind of hash

Here is the thing that makes SHA-3 worth understanding: it is not a newer, bigger SHA-2. It is a different machine inside. SHA-1 and the whole SHA-2 family are built on one design, called Merkle-Damgård, where data is fed through in blocks one after another. SHA-3 is built on something else entirely, called a sponge. You can take the name fairly literally. Your data is "absorbed" into a large pool of internal state, getting stirred in as it goes, and then the hash is "squeezed" back out of that pool. So although SHA3-256 sits next to SHA-256 on a list and produces a fingerprint of the same length, the way it gets there shares almost nothing with the older hashes.

Where SHA-3 came from

SHA-3 has a backstory, and it is a good one. After cracks began to show in SHA-1, NIST decided not to just design the next hash in-house but to run an open competition for it, announced in 2007. Teams from around the world submitted designs, dozens of them, and they were whittled down in public over several years. The winner, chosen in 2012, was an algorithm called Keccak, said roughly as "ketchak", designed by Guido Bertoni, Joan Daemen, Michaël Peeters, and Gilles Van Assche. One name there is worth noting: Joan Daemen also co-designed AES, the encryption standard the world runs on, so this was a proven team. Keccak was standardised as SHA-3 in 2015.

Why have SHA-3 if SHA-2 is fine

This is the natural question, because SHA-2 is not broken, and SHA-256 is still the everyday workhorse. So why build a whole new family? The answer is insurance through difference. SHA-1 and SHA-2 are cousins under the skin, both built on that same Merkle-Damgård design. That raised an uncomfortable thought: if someone ever found a deep flaw in the design itself, it could threaten the entire line at once. SHA-3 was deliberately built on a completely different foundation so that it could not share the same fate. If trouble ever came for SHA-2, the world would already have a strong, structurally unrelated hash ready to step in. It is a backup, not a replacement, which is also why it offers the same output sizes as SHA-2. As a bonus of its design, SHA-3 is naturally immune to a subtle weakness called the length-extension attack that the SHA-2 hashes have to work around.

It is not the same as SHA-256

This catches people out, so it is worth stating plainly. SHA3-256 and SHA-256 are not the same thing, even though both give you a 256-bit, 64-character hash. They are different algorithms from different families, and the same text run through each produces two entirely different results. So if a system asks for SHA-256, do not hand it SHA3-256, and the other way around. The length matching is on purpose, to make SHA-3 an easy drop-in where it is genuinely wanted, but the values are not interchangeable.

The library doing the work

The hashing is handled by js-sha3, a small JavaScript library implementing the SHA-3 family. Your text is read as UTF-8 bytes and run through the sponge in your browser, with the 64-character hex result handed back.

Questions people ask

Is SHA3-256 the same as SHA-256?

No. They produce the same length of hash but are different algorithms from different families, and the same input gives different results. They are not interchangeable.

Is SHA-2 broken, should I switch to SHA-3?

No, SHA-2 is not broken and SHA-256 remains a fine default. SHA-3 exists as a structurally different backup, not because SHA-2 failed. Use whichever a system asks for.

Is SHA-3 faster than SHA-2?

Not usually in software, where SHA-2 often has the edge thanks to built-in processor support. SHA-3's strength is its different, resilient design, not raw speed.

Can I reverse a SHA3-256 hash?

No. It is one-way, so the original text cannot be recovered from it. The SHA-256 page explains why no hash can be reversed, and why "decrypt" tools are really just guessing.

References

1. National Institute of Standards and Technology (2015). FIPS PUB 202: SHA-3 Standard: Permutation-Based Hash and Extendable-Output Functions. https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.202.pdf
2. Bertoni, G., Daemen, J., Peeters, M., Van Assche, G. The Keccak team. https://keccak.team/
3. js-sha3, a SHA-3 and Keccak implementation for JavaScript (npm package). https://www.npmjs.com/package/js-sha3