php-bitpay-client/src/Bitpay/PrivateKey.php
2014-10-06 18:23:11 -04:00

366 lines
9.9 KiB
PHP

<?php
/**
* @license Copyright 2011-2014 BitPay Inc., MIT License
* see https://github.com/bitpay/php-bitpay-client/blob/master/LICENSE
*/
namespace Bitpay;
use Bitpay\Util\Secp256k1;
use Bitpay\Util\Gmp;
use Bitpay\Util\Util;
use Bitpay\Util\SecureRandom;
/**
* @package Bitcore
* @see https://en.bitcoin.it/wiki/List_of_address_prefixes
*/
class PrivateKey extends Key
{
/**
* @var PublicKey
*/
protected $publicKey;
/**
* @var string
*/
public $pemEncoded = '';
/**
* @var array
*/
public $pemDecoded = array();
/**
* @return string
*/
public function __toString()
{
return (string) $this->hex;
}
/**
* @return PublicKey
*/
public function getPublicKey()
{
if (null === $this->publicKey) {
$this->publicKey = new PublicKey();
$this->publicKey->setPrivateKey($this);
$this->publicKey->generate();
}
return $this->publicKey;
}
/**
* Generates an EC private key
*
* @return \Bitpay\PrivateKey
*/
public function generate()
{
if (!empty($this->hex)) {
return $this;
}
do {
$privateKey = \Bitpay\Util\SecureRandom::generateRandom(32);
$this->hex = strtolower(bin2hex($privateKey));
} while (gmp_cmp('0x'.$this->hex, '1') <= 0 || gmp_cmp('0x'.$this->hex, '0x'.Secp256k1::N) >= 0);
$this->dec = Util::decodeHex($this->hex);
return $this;
}
/**
* Checks to see if the private key value is not empty and
* the hex form only contains hexits and the decimal form
* only contains devimal digits.
*
* @return boolean
*/
public function isValid()
{
return ($this->hasValidDec() && $this->hasValidHex());
}
/**
* @return boolean
*/
public function hasValidHex()
{
return (!empty($this->hex) || ctype_xdigit($this->hex));
}
/**
* @return boolean
*/
public function hasValidDec()
{
return (!empty($this->dec) || ctype_digit($this->dec));
}
/**
* Creates an ECDSA signature of $message
*
* @return string
*/
public function sign($data)
{
if (!ctype_xdigit($this->hex)) {
throw new \Exception('The private key must be in hex format.');
}
if (empty($data)) {
throw new \Exception('You did not provide any data to sign.');
}
$e = Util::decodeHex(hash('sha256', $data));
do {
if (substr(strtolower($this->hex), 0, 2) != '0x') {
$d = '0x'.$this->hex;
} else {
$d = $this->hex;
}
$k = SecureRandom::generateRandom(32);
$k_hex = '0x'.strtolower(bin2hex($k));
$n_hex = '0x'.Secp256k1::N;
$a_hex = '0x'.Secp256k1::A;
$p_hex = '0x'.Secp256k1::P;
$Gx = '0x'.substr(Secp256k1::G, 2, 64);
$Gy = '0x'.substr(Secp256k1::G, 66, 64);
$P = new Point($Gx, $Gy);
// Calculate a new curve point from Q=k*G (x1,y1)
$R = Gmp::doubleAndAdd($k_hex, $P);
$Rx_hex = Util::encodeHex($R->getX());
$Ry_hex = Util::encodeHex($R->getY());
$Rx_hex = str_pad($Rx_hex, 64, '0', STR_PAD_LEFT);
$Ry_hex = str_pad($Ry_hex, 64, '0', STR_PAD_LEFT);
// r = x1 mod n
$r = gmp_strval(gmp_mod('0x'.$Rx_hex, $n_hex));
// s = k^-1 * (e+d*r) mod n
$edr = gmp_add($e, gmp_mul($d, $r));
$invk = gmp_invert($k_hex, $n_hex);
$kedr = gmp_mul($invk, $edr);
$s = gmp_strval(gmp_mod($kedr, $n_hex));
// The signature is the pair (r,s)
$signature = array(
'r' => Util::encodeHex($r),
's' => Util::encodeHex($s),
);
$signature['r'] = str_pad($signature['r'], 64, '0', STR_PAD_LEFT);
$signature['s'] = str_pad($signature['s'], 64, '0', STR_PAD_LEFT);
} while (gmp_cmp($r, '0') <= 0 || gmp_cmp($s, '0') <= 0);
$sig = array(
'sig_rs' => $signature,
'sig_hex' => self::serializeSig($signature['r'], $signature['s']),
);
return $sig['sig_hex']['seq'];
}
/**
* ASN.1 DER encodes the signature based on the form:
* 0x30 + size(all) + 0x02 + size(r) + r + 0x02 + size(s) + s
* http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf
*
* @param string
* @param string
* @return string
*/
public static function serializeSig($r, $s)
{
$dec = '';
$byte = '';
$seq = '';
$digits = array();
$retval = array();
for ($x = 0; $x < 256; $x++) {
$digits[$x] = chr($x);
}
$dec = Util::decodeHex($r);
while (gmp_cmp($dec, '0') > 0) {
$dv = gmp_div($dec, '256');
$rem = gmp_strval(gmp_mod($dec, '256'));
$dec = $dv;
$byte = $byte.$digits[$rem];
}
$byte = strrev($byte);
// msb check
if (gmp_cmp('0x'.bin2hex($byte[0]), '0x80') >= 0) {
$byte = chr(0x00).$byte;
}
$retval['bin_r'] = bin2hex($byte);
$seq = chr(0x02).chr(strlen($byte)).$byte;
$dec = Util::decodeHex($s);
$byte = '';
while (gmp_cmp($dec, '0') > 0) {
$dv = gmp_div($dec, '256');
$rem = gmp_strval(gmp_mod($dec, '256'));
$dec = $dv;
$byte = $byte.$digits[$rem];
}
$byte = strrev($byte);
// msb check
if (gmp_cmp('0x'.bin2hex($byte[0]), '0x80') >= 0) {
$byte = chr(0x00).$byte;
}
$retval['bin_s'] = bin2hex($byte);
$seq = $seq.chr(0x02).chr(strlen($byte)).$byte;
$seq = chr(0x30).chr(strlen($seq)).$seq;
$retval['seq'] = bin2hex($seq);
return $retval;
}
/**
* Decodes PEM data to retrieve the keypair.
*
* @param string $pem_data The data to decode.
* @return array The keypair info.
*/
public function pemDecode($pem_data)
{
$beg_ec_text = '-----BEGIN EC PRIVATE KEY-----';
$end_ec_text = '-----END EC PRIVATE KEY-----';
$decoded = '';
$ecpemstruct = array();
$pem_data = str_ireplace($beg_ec_text, '', $pem_data);
$pem_data = str_ireplace($end_ec_text, '', $pem_data);
$pem_data = str_ireplace("\r", '', trim($pem_data));
$pem_data = str_ireplace("\n", '', trim($pem_data));
$pem_data = str_ireplace(' ', '', trim($pem_data));
$decoded = bin2hex(base64_decode($pem_data));
if (strlen($decoded) < 230) {
throw new \Exception('Invalid or corrupt secp256k1 key provided. Cannot decode the supplied PEM data.');
}
$ecpemstruct = array(
'oct_sec_val' => substr($decoded, 14, 64),
'obj_id_val' => substr($decoded, 86, 10),
'bit_str_val' => substr($decoded, 106),
);
if ($ecpemstruct['obj_id_val'] != '2b8104000a') {
throw new \Exception('Invalid or corrupt secp256k1 key provided. Cannot decode the supplied PEM data.');
}
$private_key = $ecpemstruct['oct_sec_val'];
$public_key = $ecpemstruct['bit_str_val'];
if (strlen($private_key) < 64 || strlen($public_key) < 128) {
throw new \Exception('Invalid or corrupt secp256k1 key provided. Cannot decode the supplied PEM data.');
}
$this->pemDecoded = array('private_key' => $private_key, 'public_key' => $public_key);
return $this->pemDecoded;
}
/**
* Encodes keypair data to PEM format.
*
* @param array $keypair The keypair info.
* @return string The data to decode.
*/
public function pemEncode($keypair)
{
if (is_array($keypair) && (strlen($keypair[0]) < 64 || strlen($keypair[1]) < 128)) {
throw new \Exception('Invalid or corrupt secp256k1 keypair provided. Cannot decode the supplied PEM data.');
}
$dec = '';
$byte = '';
$seq = '';
$decoded = '';
$beg_ec_text = '';
$end_ec_text = '';
$ecpemstruct = array();
$digits = array();
for ($x = 0; $x < 256; $x++) {
$digits[$x] = chr($x);
}
$ecpemstruct = array(
'sequence_beg' => '30',
'total_len' => '74',
'int_sec_beg' => '02',
'int_sec_len' => '01',
'int_sec_val' => '01',
'oct_sec_beg' => '04',
'oct_sec_len' => '20',
'oct_sec_val' => $keypair[0],
'a0_ele_beg' => 'a0',
'a0_ele_len' => '07',
'obj_id_beg' => '06',
'obj_id_len' => '05',
'obj_id_val' => '2b8104000a',
'a1_ele_beg' => 'a1',
'a1_ele_len' => '44',
'bit_str_beg' => '03',
'bit_str_len' => '42',
'bit_str_val' => '00'.$keypair[1],
);
$beg_ec_text = '-----BEGIN EC PRIVATE KEY-----';
$end_ec_text = '-----END EC PRIVATE KEY-----';
$dec = trim(implode($ecpemstruct));
if (strlen($dec) < 230) {
throw new \Exception('Invalid or corrupt secp256k1 keypair provided. Cannot encode the supplied data.');
}
$dec = Util::decodeHex('0x'.$dec);
while (gmp_cmp($dec, '0') > 0) {
$dv = gmp_div($dec, '256');
$rem = gmp_strval(gmp_mod($dec, '256'));
$dec = $dv;
$byte = $byte.$digits[$rem];
}
$byte = $beg_ec_text . "\r\n" . chunk_split(base64_encode(strrev($byte)), 64) . $end_ec_text;
$this->pemEncoded = $byte;
return $byte;
}
}