Algorithm-IRCSRP2

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lib/Algorithm/IRCSRP2.pm  view on Meta::CPAN

    $self->v(Math::BigInt->new(g())->copy->bmodpow($x->bstr, N()));

    return $self->state('init');
}

sub cbc_decrypt {
    my ($self, $data) = @_;

    my $blocksize = $self->cbc_blocksize();

    die('length($data) % $blocksize != 0') unless (length($data) % $blocksize == 0);

    my $IV = substr($data, 0, $blocksize);
    $data = substr($data, $blocksize);

    my $plaintext = '';

    foreach (@{[ 0 .. (length($data) / $blocksize) - 1 ]}) {
        my $temp = $self->cipher->decrypt(substr($data, 0, $blocksize));
        my $temp2 = xorstring($temp, $IV, $blocksize);
        $plaintext .= $temp2;
        $IV = substr($data, 0, $blocksize);
        $data = substr($data, $blocksize);
    }

    return $plaintext;
}

sub cbc_encrypt {
    my ($self, $data) = @_;

    my $blocksize = $self->cbc_blocksize();

    die('length($data) % $blocksize != 0') unless (length($data) % $blocksize == 0);

    my $IV = urandom($blocksize);
    die('len(IV) == blocksize') unless (length($IV) == $blocksize);

    my $ciphertext = $IV;

    foreach (@{[ 0 .. (length($data) / $blocksize) - 1 ]}) {
        my $xored = xorstring($data, $IV, $blocksize);
        my $enc = $self->cipher->encrypt($xored);

        $ciphertext .= $enc;
        $IV = $enc;
        $data = substr($data, $blocksize);
    }

    die('len(ciphertext) % blocksize == 0') unless (length($ciphertext) % $blocksize == 0);

    return $ciphertext;
}

sub decrypt_message {
    my ($self, $msg) = @_;

    substr($msg, 0, 1, '');

    my $raw = MIME::Base64::decode_base64($msg);

lib/Algorithm/IRCSRP2.pm  view on Meta::CPAN

    my $usernamelen = ord(substr($plain, 1, 2));
    my $username = substr($plain, 2, $usernamelen);

    $msg = substr($plain, 4 + 2 + $usernamelen);

    if ($msg =~ /^\xffKEY/) {

        my $new = substr($msg, 4);

        if (length($new) != (32 + 32)) {
            die('decrypt_message: length($new) != 32 + 32 ; length is ' . length($new));
        }

        $self->debug_cb->('decrypt_message: rekeying');

        $self->session_key(substr($new, 0, 32));
        $self->mac_key(substr($new, 32, 32));
        $self->cipher(Crypt::OpenSSL::AES->new($self->session_key));

        return;
    }

lib/Algorithm/IRCSRP2.pm  view on Meta::CPAN

    return $msg;
}

sub encrypt_message {
    my ($self, $who, $msg) = @_;

    my $times = pack('L>', int(time()));

    # info = len(username) || username || timestamp
    my $infos = chr(length($who)) . $who . $times;

    # ctext = IV || AES-CBC(sessionkey, IV, "M" || info || plaintext)
    my $ctext = $self->cbc_encrypt(padto('M' . $infos . $msg, 16));

    # cmac = HM(mackey, ctext)
    my $cmac = hmac_sha256_128($self->mac_key, $ctext);

    # ircmessage = "*" || Base64(cmac || ctext)
    return '*' . MIME::Base64::encode_base64($cmac . $ctext, '');
}

lib/Algorithm/IRCSRP2/Utils.pm  view on Meta::CPAN

    my @bs = split('', $b);

    foreach my $i (@{[ 0 .. $blocksize - 1 ]}) {
        $xored .= chr(ord($as[$i]) ^ ord($bs[$i]));
    }

    return $xored;
}

sub padto {
    my ($msg, $length) = @_;

    my $L = length($msg);

    if ($L % $length) {
        $msg .= (chr(0) x ($length - $L % $length));
    }

    die('lenth($msg) % $length != 0') unless ((length($msg) % $length) == 0);

    return $msg;
}

sub hmac_sha256_128 {
    my ($key, $data) = @_;

    my $str = Digest::SHA::hmac_sha256($data, $key);
    $str = substr($str, 0, 16);