Cryptographic global variables

Solidity provides cryptographic functions for hashing values within contract functions. There are two hashing functions – SHA2 and SHA3.

The sha3 or keccak256 function converts the input into a hash based on the sha3 algorithm, while sha256 converts the input into a hash based on the sha2 algorithm. It is recommended to use the keccak256 function for hashing needs.

The following code block illustrates this:

pragma solidity >=0.7.0 <0.9.0;
contract CryptoFunctions {
    
    function CryptoDemo() pure public returns (bytes32, 
      bytes32){ 
        return (sha256("r"), keccak256("r"));
    }
    
}

The result of executing this function is shown in the following screenshot. The result of both the keccak256 and sha3 functions is the same:

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