SHAKE128 and SHAKE256 Hash Generator

What is SHAKE?

SHAKE is the extendable-output function from NIST FIPS 202, the same standard that defines SHA-3. Rather than a fixed digest, it produces as many bytes as you ask for, from 1 through 1,048,576, with 32 as the default here.

Choose SHAKE128 or SHAKE256, set a length, then hash typed text or uploaded files. Results include the raw output bytes and the lowercase hexadecimal form.

Why variable length changes what a hash is for

A fixed hash gives you a fingerprint. An extendable one gives you a deterministic byte stream of arbitrary length from a seed, which is a different and broader tool: derive several keys from one secret, generate a mask of exactly the size a protocol wants, or produce reproducible pseudorandom data from a known input.

Doing that with a fixed-length hash means chaining or counter tricks that are easy to get subtly wrong. SHAKE gives you the length directly.

Are there alternatives?

SHA3 is the fixed-length member of the same standard, and the right pick when you just want a digest. BLAKE3 also has extendable output and runs considerably faster.

For deriving keys specifically, a purpose-built KDF is usually the better answer, and passwords always belong with Argon2id Hash Generator.

Fun facts and more info

The 128 and 256 in the names are security strengths, not output lengths. SHAKE128 can emit a megabyte if you ask, and it does not become stronger for doing so. Asking for more bytes never adds security beyond the variant's strength.

Requesting a longer output does not change the earlier bytes either. The first 32 bytes of a 1000-byte SHAKE256 result are identical to a 32-byte one over the same input, so length is a stream position rather than a parameter that reshapes the whole digest.