Class BSV::Primitives::PublicKey ¶

Inherits: Object

A secp256k1 public key for address derivation and signature verification.

Public keys are points on the secp256k1 curve. They can be serialised in compressed (33-byte) or uncompressed (65-byte) form, converted to Bitcoin addresses, and used to verify ECDSA signatures.

@example Derive address from a public key

pub = private_key.public_key
pub.address #=> "1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa"

Constants¶

MAINNET_PUBKEY_HASH ¶

Address version byte for mainnet P2PKH addresses.

TESTNET_PUBKEY_HASH ¶

Address version byte for testnet P2PKH addresses.

Attributes¶

point [R] ¶

• @return [OpenSSL::PKey::EC::Point] the underlying curve point

Public Class Methods¶

from_bytes(bytes) ¶

Create a public key from raw bytes (compressed or uncompressed). - @param bytes [String] 33-byte compressed or 65-byte uncompressed encoding - @return [PublicKey]

from_hex(hex) ¶

Create a public key from a hex string. - @param hex [String] hex-encoded compressed or uncompressed public key - @return [PublicKey]

from_private_key(private_key) ¶

Derive the public key from a {PrivateKey}. - @param private_key [PrivateKey] the private key - @return [PublicKey]

Public Instance Methods¶

==(other) ¶

• @param other [Object] the object to compare
• @return [Boolean] +true+ if both keys represent the same curve point

address(network: = :mainnet) ¶

Derive a Base58Check-encoded Bitcoin address. - @param network [Symbol] +:mainnet+ or +:testnet+ - @return [String] the P2PKH address

compressed() ¶

Return the compressed (33-byte) encoding. - @return [String] compressed public key bytes

derive_child(private_key, invoice_number) ¶

Derive a child public key using BRC-42 key derivation.

Computes HMAC-SHA256(key: ECDH_shared_secret, msg: invoice_number) and adds the corresponding curve point to this public key. The result matches the public key of {PrivateKey#derive_child} with the same inputs, enabling public-key-only derivation. - @param private_key [PrivateKey] the counterparty's private key - @param invoice_number [String] the invoice number (UTF-8) - @return [PublicKey] the derived child public key

derive_shared_secret(private_key) ¶

Derive an ECDH shared secret with another party's private key.

Computes the shared point by multiplying this public key by the given private key's scalar. The result is commutative: alice_pub.derive_shared_secret(bob_priv) == bob_pub.derive_shared_secret(alice_priv)

This is the foundational primitive for BRC-42 key derivation, BRC-77/78 messaging, and ECIES encryption. - @param private_key [PrivateKey] the other party's private key - @return [PublicKey] the shared secret as a public key (curve point)

hash160() ¶

Compute the Hash160 (RIPEMD-160 of SHA-256) of the compressed public key. - @return [String] 20-byte public key hash

initialize(point) ¶

• @param point [OpenSSL::PKey::EC::Point] a point on the secp256k1 curve
• @raise [ArgumentError] if point is not an EC point or is at infinity
• @return [PublicKey] a new instance of PublicKey

to_hex(compressed: = true) ¶

Return the public key as a hex string. - @param compressed [Boolean] whether to use compressed encoding (default: true) - @return [String] hex-encoded public key

uncompressed() ¶

Return the uncompressed (65-byte) encoding. - @return [String] uncompressed public key bytes

verify(hash, signature) ¶

Verify an ECDSA signature against a message hash. - @param hash [String] 32-byte message digest - @param signature [Signature] the signature to verify - @return [Boolean] +true+ if the signature is valid