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sharplispers / ironclad

A cryptographic toolkit written in Common Lisp
BSD 3-Clause "New" or "Revised" License
166 stars 28 forks source link

Please include Ethereum's version of KECCAK256 #7

Closed phmarek closed 6 years ago

phmarek commented 6 years ago

The difference seems to be the LFSR used to build the round constants: https://ethereum.stackexchange.com/questions/30369/difference-between-keccak256-and-sha3

One example hash input and output value pair can be taken from https://github.com/ethereum/solidity/blob/develop/test/liblll/EndToEndTest.cpp#L566

Thanks a lot!

phmarek commented 6 years ago

For reference, here's the calculation of the round constants for the SHA3 case:

(loop with LFSR = #x01
      for i from 0 below 24
      for word = 0
      do (dotimes (j 7)
           (when (oddp LFSR)
             (let ((bit-pos (1- (ash 1 j))))
               (setf word
                     (logxor word 
                             (ash 1 bit-pos)))))
           (setf LFSR 
                 (if (zerop (logand LFSR #x80))
                   (ash LFSR 1)
                   (logxor (ash LFSR 1)
                           #x71))))
      do (format t "~16,'0x~%" word))

For the Ethereum KECCAK256 version the LFSR needs to start with 6.

Please advise how the changed constants should be integrated with the optimized code - and whether all the keccak-names should be fixed to be sha3...

Thanks a lot!

glv2 commented 6 years ago

I added the original Keccak digests (i.e. SHA3 with different padding) in commit 6764e984082221920acadaca1b3186b41b2c12b5.

Hashing with :keccak/256 gives the same result as Ethereum's Keccak-256 (tested with the value in https://ethereum.stackexchange.com/questions/550/which-cryptographic-hash-function-does-ethereum-use).