A cryptographic hash function is an algorithm that takes an arbitrary amount of data as input and produces the enciphered text of fixed size. Even a slight change in the input gives a completely different output.
Solidity provides the following cryptographic functions: Function Properties
keccak256(bytes memory) returns (bytes32) Computes the Keccak-256 hash of the input sha256(bytes memory) returns (bytes32) Computes the SHA-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 used for cryptography or return
Zero if an error occurs. The parameters correspond to ECDSA
Ethereum uses Keccak for hashing which is similar but not the same as SHA_256. For proof of work, it uses a custom scheme called ethash which is designed to be ASIC-resistant.
Example: In the below example, a smart contract is created to take a string as input and give an 8 digit hash as an output.