Decodes a public key as ECPoint from a compressed public key string.

If unsure, .restore_public_key should be used.

Parameters:

• pub (String): the public key in prefixed compressed format.
• prime (BigInt): the prime number that shapes the field, default: EC_PRIME_P.

Secp256k1::Util.decode_compressed_public_key "03d885aed4bcaf3a8c95a57e3be08caa1bd6a060a68b9795c03129073597fcb19a"

Returns an ECPoint containing the public key.

Raises if compressed public key is malformed or comes with invalid prefix.

A helper function to generate 32 pseudo-random bytes within the elliptic curve field size of EC_ORDER_N.

Secp256k1::Util.new_private_key
# => "b795cd2c5ce0cc632ca1f65e921b9c751b363e97fcaeec81c02a85b763448268"

Exports the compressed public key from an ECPoint with either the prefix "02" or "03".

The prefix can be later used to recover the y coordinate of the public key, see .decode_compressed_public_key. Bitcoin uses this format to generate shorter addresses as compared to using uncompressed keys.

Parameters:

• p (ECPoint): the public key point which shall be compressed.

Secp256k1::Util.public_key_compressed_prefix my_public_key
# => "03d885aed4bcaf3a8c95a57e3be08caa1bd6a060a68b9795c03129073597fcb19a"

Gets a public key from a private key.

This is basically a wrapper function to perform an elliptic curve multiplication with the generator point g and a provided private key priv.

Parameters:

• priv (BigInt): the private key to be used.

Secp256k1::Util.public_key_from_private BigInt.new("b795cd2c5ce0cc632ca1f65e921b9c751b363e97fcaeec81c02a85b763448268", 16)

Returns an ECPoint containing the public key.

Exports the uncompressed public key from an ECPoint without prefix.

Ethereum uses this format to generate addresses. For prefixed uncompressed public keys, see .public_key_uncompressed_prefix.

Parameters:

• p (ECPoint): the public key point which shall be uncompressed.

Secp256k1::Util.public_key_uncompressed my_public_key
# => "d885aed4bcaf3a8c95a57e3be08caa1bd6a060a68b9795c03129073597fcb19a67299d1cf25955e9b6425583cbc33f4ab831f5a31ef88c7167e9eb714cc758a5"

Exports the uncompressed public key from an ECPoint with prefix "04".

Bitcoin uses this format to generate uncompressed addresses. For unprefixed public keys, see .public_key_uncompressed.

Parameters:

• p (ECPoint): the public key point which shall be uncompressed.

Secp256k1::Util.public_key_uncompressed_prefix my_public_key
# => "04d885aed4bcaf3a8c95a57e3be08caa1bd6a060a68b9795c03129073597fcb19a67299d1cf25955e9b6425583cbc33f4ab831f5a31ef88c7167e9eb714cc758a5"

Detects public key type and tries to restore the ECPoint from it.

Parameters:

• pub (String): the public key in any format.
• prime (BigInt): the prime number that shapes the field, default: EC_PRIME_P.

Secp256k1::Util.restore_public_key "d885aed4bcaf3a8c95a57e3be08caa1bd6a060a68b9795c03129073597fcb19a67299d1cf25955e9b6425583cbc33f4ab831f5a31ef88c7167e9eb714cc758a5"

Returns an ECPoint containing the public key.

Raises if public key format is unknown.

A generic utility to encode single hex bytes as strings, e.g., "07"

Parameters:

• i (Int32): the integer to be formatted as padded hex byte.

Secp256k1::Util.to_padded_hex_01 7
# => "07"

An utility tool to ensure hex keys are always 32 bytes; it pads the number with leading zeros if it's shorter.

Parameters:

• i (BigInt): the integer to be formatted as padded hex byte string.

Secp256k1::Util.to_padded_hex_32 BigInt.new 7
# => "0000000000000000000000000000000000000000000000000000000000000007"