cSHAKE128 File Hash
Calculate a customizable cSHAKE128 digest from a local file or URL with configurable output length and domain separation. Read more
What is cSHAKE128?
cSHAKE128 is a customizable extendable-output function defined in NIST SP 800-185. It hashes raw file bytes and uses Function Name and Customization parameters for domain separation. Empty values make it equivalent to SHAKE128 File Hash at the same output length.
How to use this file hash calculator
Choose a local file or URL, set the output length, and enter the parameters required by your protocol. Function Name is intended for formally defined functions; application-specific labels normally belong in Customization. Local files stay in your browser, while URL access depends on CORS.
Result example
A file containing exactly abc, with empty Function Name and Customization and a 256-bit output, produces 5881092dd818bf5cf8a3ddb793fbcba74097d5c526a6d35f97b83351940f2cc8 in Hex. The filename is not part of the input.
Important limitations
cSHAKE128 is unkeyed; customization separates uses but does not authenticate a file. Use KMAC128 when a secret key is required, and obtain comparison values through a trusted channel.
Frequently asked questions
Why does my result differ from another tool?
Check the raw file bytes, output length, Function Name, Customization, and parameter encodings. All must match exactly.
Can I use the result to verify a download?
Yes, when the protocol defines every parameter and the expected digest is trusted. For encoded text input, use the cSHAKE128 text calculator.
