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lib/Blockchain/Ethereum/Keystore/Keyfile.pm  view on Meta::CPAN

use Carp;
use File::Slurp;
use JSON::MaybeXS qw(decode_json encode_json);
use Crypt::PRNG;
use Net::SSH::Perl::Cipher;

use Blockchain::Ethereum::Keystore::Key;
use Blockchain::Ethereum::Keystore::Keyfile::KDF;

sub new {
    my ($class, %params) = @_;

    my $self = bless {}, $class;
    for (qw(cipher ciphertext mac version iv kdf id private_key)) {
        $self->{$_} = $params{$_} if exists $params{$_};
    }

    return $self;
}

sub cipher {
    shift->{cipher};
}

sub ciphertext {
    shift->{ciphertext};
}

sub mac {
    shift->{mac};
}

sub version {
    shift->{version};
}

sub iv {
    shift->{iv};
}

sub kdf {
    shift->{kdf};
}

sub id {
    shift->{id};
}

sub private_key {
    shift->{private_key};
}

sub _json {
    return shift->{json} //= JSON::MaybeXS->new(utf8 => 1);
}

sub import_file {
    my ($self, $file_path, $password) = @_;

    my $content = read_file($file_path);
    my $decoded = $self->_json->decode(lc $content);

    return $self->_from_object($decoded, $password);
}

sub _from_object {
    my ($self, $object, $password) = @_;

    my $version = $object->{version};

    croak 'Version not supported' unless $version && $version == 3;

    return $self->_from_v3($object, $password);
}

sub _from_v3 {
    my ($self, $object, $password) = @_;

    my $crypto = $object->{crypto};

    $self->{cipher}     = 'AES128_CTR';
    $self->{ciphertext} = $crypto->{ciphertext};
    $self->{mac}        = $crypto->{mac};
    $self->{version}    = 3;
    $self->{iv}         = $crypto->{cipherparams}->{iv};

    my $header = $crypto->{kdfparams};

    $self->{kdf} = Blockchain::Ethereum::Keystore::Keyfile::KDF->new(
        algorithm => $crypto->{kdf},     #
        dklen     => $header->{dklen},
        n         => $header->{n},
        p         => $header->{p},
        r         => $header->{r},
        c         => $header->{c},
        prf       => $header->{prf},
        salt      => $header->{salt});

    $self->{private_key} = $self->_private_key($password);

    return $self;
}

sub change_password {
    my ($self, $old_password, $new_password) = @_;

    return $self->import_key($self->_private_key($old_password), $new_password);
}

sub _private_key {
    my ($self, $password) = @_;

    return $self->private_key if $self->private_key;

    my $cipher = Net::SSH::Perl::Cipher->new(
        $self->cipher,    #
        $self->kdf->decode($password),
        pack("H*", $self->iv));

    my $key = $cipher->decrypt(pack("H*", $self->ciphertext));

    return Blockchain::Ethereum::Keystore::Key->new(private_key => $key);
}