Does anyone know why NISTs SHA3 256 output Hash for the 1600 bit file is different to other SHA3 256 output hashes? I have been trying to implement my own SHA3 256 function in python to try and learn and understand how it works. I have been comparing my hashes with an online sha3 tool found here https://emn178.github.io/online-tools/sha3_256.html and the test files on the NIST website found here https://csrc.nist.gov/projects/cryptographic-standards-and-guidelines/example-values. I realised that the output hash found in the 1600 bit file found on the NIST file is different from the one on the online tool. I have even used a python sha3 library and the result of the hash is the same as the one on the online tool. Does anyone know why the NIST output hash is different? I know NIST has made some changes to SHA3 padding but I am still unsure.
NIST gave the 1600-bit input as a bit-string, with each byte in LSb first bit order. So 1 1 0 0 0 1 0 1 is A3, not C5 as one would expect.