⚠️ Warning

You are welcome to use this at your own risk. No liabilities, no warranty, check LICENSE file.

ECDSA lib for PHP

Easy interface and to the point API for following curves and features:

• Secp256k1 (using GMP calculations)
• Secp256k1_RPC (using bitcoin's original libsecp256k1 written in C lang, requires furqansiddiqui/secp256k1-rpc RPC server)
• Built-in support for RFC6979 for generation of deterministic yet secure k nonce.

Prerequisites

• PHP ^8.2
• ext-gmp
• ext-curl (for furqansiddiqui/secp256k1-rpc)

Installation

composer require furqansiddiqui/ecdsa-php

Documentation

KeyPair

Method	Returns	Description
__construct	-	Requires EllipticCurveInterface and AbstractByteArray (private key) as arguments.
public	PublicKey	Creates and holds on to instance of PublicKey for corresponding private key.
sign	Signature	Creates a signature. Depending on ECC curve passed in constructor, the returning Signature instance may or may not have recovery id set.
signRecoverable	Signature	Creates a recoverable signature. This signature will always contain a recovery id.
findRecoveryId	int	Finds a recovery id for given Signature and message hash.
verify	bool	Verifies a signature with given Signature and message hash.
verifyPublicKey	bool	Verifies a recoverable signature. It is possible to override recovery id directly in arguments for this method if Signature does not have a recovery id set.

PublicKey

Constructor	Arguments	Description
fromDER	AbstractByteArray	Expects 65 byte long DER encoded public key starting with \x04 prefix.

$pub = PublicKey::fromDER(Buffer::fromBase16("hex-string"))

Method	Returns	Description
getUnCompressed	Buffer	Gets DER serialized uncompressed public key. 65 bytes long including prefix of \x04.
getCompressed	Buffer	Get DER serialized compressed public key. 33 bytes long including \x02 or \x03 prefix.
compare	int	Compares with another PublicKey instance. Returns 0 if identical OR a negative value if public keys do not match.

Signature

Property	Type	Description
r	AbstractByteArray	Signature value r. (readonly)
s	AbstractByteArray	Signature value s. (readonly)
recoveryId	int	Recovery ID (v) for signature. Defaults to -1 when there is no recovery id available. (readonly)

Constructor	Arguments	Description
fromDER	AbstractByteArray	Unserializes a DER encoded signature .
fromCompact	AbstractByteArray	Unserializes a 65 byte compact signature where first byte is v (recovery id) followed by 32 bytes each for r and s.

Method	Returns	Description
getDER	Buffer	Returns a DER encoded signature starts with \x30 byte.
compare	int	Compares with another Signature instance. Returns 0 if identical OR a negative value if signatures do not match.

EllipticCurveInterface

Method	Returns	Description
validatePrivateKey	bool	Validates a private key.
generatePublicKey	PublicKey	Generates public key from given private key.
getPublicKeyFromCompressed	PublicKey	Retrieves uncompressed public key from given compressed variant. Accepted prefixes are \x02 or \x03.
sign	Signature	Creates a signature from private key and message hash. This method may or may not retrieve recovery id depending on ECC curve used. Therefore, recovery Id may have to be retrieved separately.
recoverPublicKeyFromSignature	PublicKey	Recovers a public key from given Signature and message hash. Can be used to retrieve recovery id in 1-4 iterations.
verify	bool	Verifies a signature with given PublicKey, Signature and message hash.

Difference in Secp256k1 variants

Method	Secp256k1_GMP	Secp256k1_RPC
sign	🚫 Does not return recovery id with signature r and s values. It is recommended to use KeyPair which provides signRecoverable and findRecoveryId methods.	✅ Returns recovery id alongside signature.