= Cryptography

[.readme-notice]
NOTE: This document is better viewed at https://docs.openzeppelin.com/contracts/api/utils/cryptography

A collection of contracts and libraries that implement various signature validation schemes and cryptographic primitives. These utilities enable secure authentication, multisignature operations, and advanced cryptographic operations in smart contracts.

 * {ECDSA}, {MessageHashUtils}: Libraries for interacting with ECDSA signatures.
 * {P256}: Library for verifying and recovering public keys from secp256r1 signatures.
 * {RSA}: Library with RSA PKCS#1 v1.5 signature verification utilities.
 * {SignatureChecker}: A library helper to support regular ECDSA from EOAs as well as ERC-1271 signatures for smart contracts.
 * {Hashes}: Commonly used hash functions.
 * {MerkleProof}: Functions for verifying https://en.wikipedia.org/wiki/Merkle_tree[Merkle Tree] proofs.
 * {EIP712}: Contract with functions to allow processing signed typed structure data according to https://eips.ethereum.org/EIPS/eip-712[EIP-712].
 * {ERC7739Utils}: Utilities library that implements a defensive rehashing mechanism to prevent replayability of smart contract signatures based on ERC-7739.
 * {AbstractSigner}: Abstract contract for internal signature validation in smart contracts.
 * {ERC7739}: An abstract contract to validate signatures following the rehashing scheme from {ERC7739Utils}.
 * {SignerECDSA}, {SignerP256}, {SignerRSA}: Implementations of an {AbstractSigner} with specific signature validation algorithms.
 * {SignerERC7702}: Implementation of {AbstractSigner} that validates signatures using the contract's own address as the signer, useful for delegated accounts following EIP-7702.
 * {SignerERC7913}, {MultiSignerERC7913}: Implementations of {AbstractSigner} that validate signatures based on ERC-7913. Including a simple multisignature scheme.
 * {ERC7913P256Verifier}, {ERC7913RSAVerifier}: Ready to use ERC-7913 signature verifiers for P256 and RSA keys.

== Utils

{{ECDSA}}

{{MessageHashUtils}}

{{P256}}

{{RSA}}

{{SignatureChecker}}

{{Hashes}}

{{MerkleProof}}

{{EIP712}}

{{ERC7739Utils}}

== Abstract Signers

{{AbstractSigner}}

{{ERC7739}}

{{SignerECDSA}}

{{SignerP256}}

{{SignerRSA}}

{{SignerERC7702}}

{{SignerERC7913}}

{{MultiSignerERC7913}}

== Verifiers

{{ERC7913P256Verifier}}

{{ERC7913RSAVerifier}}