”;
Solidity provides inbuilt cryptographic functions as well. Following are important methods −
-
keccak256(bytes memory) returns (bytes32) − computes the Keccak-256 hash of the input.
-
ripemd160(bytes memory) returns (bytes20) − compute RIPEMD-160 hash of the input.
-
sha256(bytes memory) returns (bytes32) − computes the SHA-256 hash of the input.
-
ecrecover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) returns (address) − recover the address associated with the public key from elliptic curve signature or return zero on error. The function parameters correspond to ECDSA values of the signature: r – first 32 bytes of signature; s: second 32 bytes of signature; v: final 1 byte of signature. This method returns an address.
Following example shows the usage of cryptographic function in Solidity.
Example
pragma solidity ^0.5.0;
contract Test {
function callKeccak256() public pure returns(bytes32 result){
return keccak256("ABC");
}
}
Run the above program using steps provided in Solidity First Application chapter.
Output
0: bytes32: result 0xe1629b9dda060bb30c7908346f6af189c16773fa148d3366701fbaa35d54f3c8
”;