NAME
Bitcoin::Crypto - Bitcoin cryptography in Perl
SYNOPSIS
use Bitcoin::Crypto qw(btc_extprv);
# extended keys are used for mnemonic generation and key derivation
my $mnemonic = btc_extprv->generate_mnemonic();
say "your mnemonic code is: $mnemonic";
my $master_key = btc_extprv->from_mnemonic($mnemonic);
my $derived_key = $master_key->derive_key("m/0'");
# basic keys are used for signatures and addresses
my $priv = $derived_key->get_basic_key();
my $pub = $priv->get_public_key();
say "private key: " . $priv->to_wif();
say "public key: " . $pub->to_hex();
say "address: " . $pub->get_segwit_address();
my $message = "Hello CPAN";
my $signature = $priv->sign_message($message);
if ($pub->verify_message($message, $signature)) {
say "successfully signed message '$message'";
say "signature: " . unpack "H*", $signature;
}DESCRIPTION
Cryptographic module for common Bitcoin-related tasks and key pair management.
SCOPE
This module allows you to do basic tasks for Bitcoin such as:
creating extended keys and utilizing bip32 key derivation
creating private key / public key pairs
address generation (in legacy, compatibility and segwit formats)
signature generation and verification
importing / exporting using popular mediums (WIF, mnemonic, hex)
using custom (non-Bitcoin) networks
This module won't help you with:
serializing transactions
using any Bitcoin CLI tools / clients
connecting to Bitcoin network
WHERE TO START?
Documentation and examples in this module assume you're already familiar with the basics of Bitcoin protocol and asymmetric cryptography. If that's not the case, start with learning about those topics.
If you like to learn by example, dive right into the examples directory.
There are many things that you may want to achieve with this module. Common topics include:
create a key pair for signature or address generation
Start with Bitcoin::Crypto::Key::Private if you already have some data you want to use as a private key entropy (like Bitcoin's WIF format or hex data). If you'd like to generate a key and get a list of words (a mnemonic), Bitcoin::Crypto::Key::ExtPrivate is what you want.
generate many keys at once
Bitcoin::Crypto::Key::ExtPrivate will allow you to derive as many keys as you want from a master key, so you won't have to store multiple private key seeds. Bitcoin::Crypto::Key::ExtPublic can be then used to derive public keys lazily. (Note: storing extended public keys together with private keys in a hot storage will put your extended private key at risk!)
work with other cryptocurrencies
You can work with any cryptocurrency as long as it is based on the same fundamentals as Bitcoin. You have to register a network in Bitcoin::Crypto::Network first, with the protocol data valid for your cryptocurrency.
serialize a Bitcoin script
Bitcoin::Crypto::Script will help you build and serialize a script, but not run it.
work with Bitcoin-related encodings
HOW TO READ THE DOCUMENTATION?
Most functions in this documentation have a code line showcasing the arguments used by the function.
These lines are not meant to be valid perl. They're there for you to understand what arguments the function expects.
Most packages in this module have the types of their thrown exceptions documented near the bottom of the document. The exceptions section may be useful to understand which types of exceptions can be thrown when using functions or methods from the package and what they mean. It is not meant to be a full list of exceptions a function can throw and unblessed errors may still be raised.
SHORTCUT FUNCTIONS
This package exports the following functions when asked for them. They are shourtcut functions and will load needed packages and return their names. You can then use names of loaded packages to instantiate them however you want. You can also load all of them with the :all tag in import. These functions can be used as follows:
use Bitcoin::Crypto qw(btc_pub);
# loads Bitcoin::Crypto::Key::Public and returns package name
# we can now use it to run its methods
my $public_key = btc_pub->from_hex($hex_data);btc_extprv
Loads Bitcoin::Crypto::Key::ExtPrivate
btc_prv
Loads Bitcoin::Crypto::Key::Private
btc_extpub
Loads Bitcoin::Crypto::Key::ExtPublic
btc_pub
Loads Bitcoin::Crypto::Key::Public
btc_script
Loads Bitcoin::Crypto::Script
DISCLAIMER
Although the module was written with an extra care and appropriate tests are in place asserting compatibility with many Bitcoin standards, due to complexity of the subject some bugs may still be present. In the world of digital money, a single bug may lead to losing funds. I encourage anyone to test the module themselves, review the test cases and use the module with care. Suggestions for improvements and more edge cases to test will be gladly accepted, but there is no warranty on your funds being manipulated by this module.
SPEED
Since most of the calculations are delegated to the XS (and further to libtommath and libtomcrypt) most tasks should be fairly quick to finish, in Perl definition of quick. The module have a little bit of startup time because of Moo and Type::Tiny, measured in miliseconds. The biggest runtime bottleneck seem to be the key derivation mechanism, which imports a key once for every derivation path part. Some tasks, like signature generation and verification, should be very fast thanks to libtomcrypt doing all the heavy lifting. All in all, the module should be able to handle any task which does not require brute forcing (like vanity address generation).
TODO
Taproot compatibility
Better test coverage
SEE ALSO
AUTHOR
Bartosz Jarzyna <bbrtj.pro@gmail.com>
COPYRIGHT AND LICENSE
Copyright (C) 2018 - 2022 by Bartosz Jarzyna
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.