ParallelHashXOF256

What is ParallelHashXOF256?

ParallelHashXOF256 is the extendable-output form of ParallelHash256 based on cSHAKE256. Its internal encoding does not commit to a fixed output length before output begins. This calculator reads text, a local file, or a file URL and returns the requested number of output bits in the selected encoding. Identical input bytes, block size, customization string, and output length produce the same result.

How to use this hash calculator

Choose Text, Local File, or File URL as the source. For text, select the input encoding. Set Block Size (B) as a byte count, the output length, and an optional Customization string. Use Hex when comparing technical test vectors, or Base64 when a compact text representation is more convenient.

Result example

With UTF-8 abc, block size 8 bytes, empty customization, and a 512-bit output, ParallelHashXOF256 is fa4878e1d900892eb773cb8fe9f61e54ece40f8caf7010a712c424d98267c7f4d202dbed1a9a20c475e16e8422625c74f6dd1ebd00a1536dab2011386ccd4d93 in Hex. The same inputs produce a different digest under ordinary ParallelHash256 because the two modes encode output length differently.

Important limitations

ParallelHashXOF256 output intentionally differs from ordinary ParallelHash256, even when the input, block size, customization string, and displayed output length are the same. ParallelHash is unkeyed; use KMACXOF256 when keyed authentication is required.

ParallelHashXOF is specified in NIST SP 800-185.

Frequently asked questions

Why does my result differ from another tool?

Check the exact input bytes, Block Size (B) in bytes, customization string, output length, and whether the other tool uses ParallelHash or ParallelHashXOF.

Can I use the result to verify data?

Yes, if every parameter is defined by the protocol and the expected value is trusted. Matching an untrusted digest copied from the same location does not establish authenticity.