Math-Crypto Functions.md

79 - Math-Crypto Functions

Mathematical and Cryptographic Functions:

1. addmod(uint x, uint y, uint k) returns (uint): compute (x + y) % k where the addition is performed with arbitrary precision and does not wrap around at 2**256. Assert that k != 0 starting from version 0.5.0.

2. mulmod(uint x, uint y, uint k) returns (uint): compute (x * y) % k where the multiplication is performed with arbitrary precision and does not wrap around at 2**256. Assert that k != 0 starting from version 0.5.0.

3. keccak256(bytes memory) returns (bytes32): compute the Keccak-256 hash of the input

4. sha256(bytes memory) returns (bytes32): compute the SHA-256 hash of the input

5. ripemd160(bytes memory) returns (bytes20): compute RIPEMD-160 hash of the input

6. 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. ecrecover returns an address, and not an address payable.

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Slide Screenshot

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Slide Deck

• addmod() & mulmod()
• keccak256(bytes memory)
• sha256(bytes memory)
• ripemd160(bytes memory)
• ecrecover(bytes32 hash, uint8 v, bytes32 r, bytes32 s)

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References

• Youtube Reference