Decodes a public key as EC_Point 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 EC_Point 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 EC_Point 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 (EC_Point): 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 EC_Point containing the public key.

Exports the uncompressed public key from an EC_Point without prefix.

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

Parameters:

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

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

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

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

Parameters:

• p (EC_Point): 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 EC_Point 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 EC_Point 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"