Cryptographic Primitives
========================

Here we implement the various cryptographic primitives needed for KEVM.

.. code-block:: k

    module KRYPTO
        imports STRING-SYNTAX

-  ``Keccak256`` takes a string and returns a 64-character hex-encoded
   string of the 32-byte keccak256 hash of the string.
-  \`Sha256' takes a String and returns a 64-character hex-encoded
   string of the 32-byte SHA2-256 hash of the string.
-  \`RipEmd160' takes a String and returns a 40-character hex-encoded
   string of the 20-byte RIPEMD160 hash of the string.
-  ``ECDSARecover`` takes a 32-character byte string of a message, v, r,
   s of the signed message and returns the 64-character public key used
   to sign the message. See `this StackOverflow
   post <https://ethereum.stackexchange.com/questions/15766/what-does-v-r-s-in-eth-gettransactionbyhash-mean>`__
   for some information about v, r, and s.

.. code-block:: k

        syntax String ::= Keccak256 ( String )                            [function, hook(KRYPTO.keccak256)]
                        | ECDSARecover ( String , Int , String , String ) [function, hook(KRYPTO.ecdsaRecover)]
                        | Sha256 ( String )                               [function, hook(KRYPTO.sha256)]
                        | RipEmd160 ( String )                            [function, hook(KRYPTO.ripemd160)]
    endmodule