SHA2 Hash Generator

What the SHA-2 generator does

This generates a SHA-2 hash of your text. Here is the honest detail up front, because the name is a little loose: SHA-2 is not one algorithm but a whole family of them, and this tool gives you the one almost everyone means by SHA-2, namely SHA-256, as a 64-character hex fingerprint. Type or paste your text, press Convert, and copy or download the result.

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 SHA-256 hash appears, ready to Copy or Download.

SHA-2 is a family, not a single hash

It helps to know what SHA-2 actually refers to. It is a set of related hash functions published by the United States standards body NIST, all defined in the same standard. The members differ mainly in how long a fingerprint they produce: SHA-224, SHA-256, SHA-384, and SHA-512, along with a couple of less common cousins, SHA-512/224 and SHA-512/256. Under the surface they run on two engines, a 32-bit one that powers SHA-224 and SHA-256, and a 64-bit one that powers SHA-384 and SHA-512. So "SHA-2" is the surname of a family, and each member is a specific hash with its own digest length. If you want one of the other sizes, this site has a dedicated tool for each: SHA-224, SHA-384, and SHA-512.

Why this gives you SHA-256

Of the whole family, SHA-256 is the one in everyday use, by a wide margin. It strikes the balance most people want between a strong, roomy fingerprint and good speed, and it is what sits behind website certificates, file checksums, and Bitcoin. So when a form, a guide, or a colleague says "use SHA-2" without naming a size, SHA-256 is what they mean, and it is what this tool produces. The output here is identical to what the dedicated SHA-256 tool gives, which is also where the fuller story of how SHA-256 works and where it is used is laid out.

The library doing the work

The hashing is handled by js-sha256, a small, widely used JavaScript implementation. Your text is read as UTF-8 bytes and run through SHA-256 in your browser, and the 64-character hex result comes straight back.

Questions people ask

Is SHA-2 the same as SHA-256?

Not exactly. SHA-2 is the family, and SHA-256 is its most-used member. Because that is what nearly everyone means by SHA-2, this tool produces SHA-256.

Which member does this give me?

SHA-256, a 64-character hex hash. It is the same output as the dedicated SHA-256 tool.

Can I get the other sizes?

Yes. Use the SHA-224, SHA-384, or SHA-512 tools for those digest lengths.

Can I reverse a SHA-2 hash?

No. A hash keeps only a fingerprint of your text and discards the rest, so there is nothing to turn back into the original. The SHA-256 page explains why in full.

References

1. National Institute of Standards and Technology (2015). FIPS PUB 180-4: Secure Hash Standard (SHS). https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.180-4.pdf
2. js-sha256, a SHA-256 implementation for JavaScript (npm package). https://www.npmjs.com/package/js-sha256