1<?php 2 3/** 4 * RSA Private Key 5 * 6 * @category Crypt 7 * @package RSA 8 * @author Jim Wigginton <terrafrost@php.net> 9 * @copyright 2015 Jim Wigginton 10 * @license http://www.opensource.org/licenses/mit-license.html MIT License 11 * @link http://phpseclib.sourceforge.net 12 */ 13 14namespace phpseclib3\Crypt\RSA; 15 16use phpseclib3\Crypt\Common; 17use phpseclib3\Crypt\Random; 18use phpseclib3\Crypt\RSA; 19use phpseclib3\Crypt\RSA\Formats\Keys\PSS; 20use phpseclib3\Exception\UnsupportedFormatException; 21use phpseclib3\Math\BigInteger; 22 23/** 24 * Raw RSA Key Handler 25 * 26 * @package RSA 27 * @author Jim Wigginton <terrafrost@php.net> 28 * @access public 29 */ 30class PrivateKey extends RSA implements Common\PrivateKey 31{ 32 use Common\Traits\PasswordProtected; 33 34 /** 35 * Primes for Chinese Remainder Theorem (ie. p and q) 36 * 37 * @var array 38 * @access private 39 */ 40 protected $primes; 41 42 /** 43 * Exponents for Chinese Remainder Theorem (ie. dP and dQ) 44 * 45 * @var array 46 * @access private 47 */ 48 protected $exponents; 49 50 /** 51 * Coefficients for Chinese Remainder Theorem (ie. qInv) 52 * 53 * @var array 54 * @access private 55 */ 56 protected $coefficients; 57 58 /** 59 * Public Exponent 60 * 61 * @var mixed 62 * @access private 63 */ 64 protected $publicExponent = false; 65 66 /** 67 * RSADP 68 * 69 * See {@link http://tools.ietf.org/html/rfc3447#section-5.1.2 RFC3447#section-5.1.2}. 70 * 71 * @access private 72 * @param \phpseclib3\Math\BigInteger $c 73 * @return bool|\phpseclib3\Math\BigInteger 74 */ 75 private function rsadp($c) 76 { 77 if ($c->compare(self::$zero) < 0 || $c->compare($this->modulus) > 0) { 78 throw new \OutOfRangeException('Ciphertext representative out of range'); 79 } 80 return $this->exponentiate($c); 81 } 82 83 /** 84 * RSASP1 85 * 86 * See {@link http://tools.ietf.org/html/rfc3447#section-5.2.1 RFC3447#section-5.2.1}. 87 * 88 * @access private 89 * @param \phpseclib3\Math\BigInteger $m 90 * @return bool|\phpseclib3\Math\BigInteger 91 */ 92 private function rsasp1($m) 93 { 94 if ($m->compare(self::$zero) < 0 || $m->compare($this->modulus) > 0) { 95 throw new \OutOfRangeException('Signature representative out of range'); 96 } 97 return $this->exponentiate($m); 98 } 99 100 /** 101 * Exponentiate 102 * 103 * @param \phpseclib3\Math\BigInteger $x 104 * @return \phpseclib3\Math\BigInteger 105 */ 106 protected function exponentiate(BigInteger $x) 107 { 108 switch (true) { 109 case empty($this->primes): 110 case $this->primes[1]->equals(self::$zero): 111 case empty($this->coefficients): 112 case $this->coefficients[2]->equals(self::$zero): 113 case empty($this->exponents): 114 case $this->exponents[1]->equals(self::$zero): 115 return $x->modPow($this->exponent, $this->modulus); 116 } 117 118 $num_primes = count($this->primes); 119 120 if (!static::$enableBlinding) { 121 $m_i = [ 122 1 => $x->modPow($this->exponents[1], $this->primes[1]), 123 2 => $x->modPow($this->exponents[2], $this->primes[2]) 124 ]; 125 $h = $m_i[1]->subtract($m_i[2]); 126 $h = $h->multiply($this->coefficients[2]); 127 list(, $h) = $h->divide($this->primes[1]); 128 $m = $m_i[2]->add($h->multiply($this->primes[2])); 129 130 $r = $this->primes[1]; 131 for ($i = 3; $i <= $num_primes; $i++) { 132 $m_i = $x->modPow($this->exponents[$i], $this->primes[$i]); 133 134 $r = $r->multiply($this->primes[$i - 1]); 135 136 $h = $m_i->subtract($m); 137 $h = $h->multiply($this->coefficients[$i]); 138 list(, $h) = $h->divide($this->primes[$i]); 139 140 $m = $m->add($r->multiply($h)); 141 } 142 } else { 143 $smallest = $this->primes[1]; 144 for ($i = 2; $i <= $num_primes; $i++) { 145 if ($smallest->compare($this->primes[$i]) > 0) { 146 $smallest = $this->primes[$i]; 147 } 148 } 149 150 $r = BigInteger::randomRange(self::$one, $smallest->subtract(self::$one)); 151 152 $m_i = [ 153 1 => $this->blind($x, $r, 1), 154 2 => $this->blind($x, $r, 2) 155 ]; 156 $h = $m_i[1]->subtract($m_i[2]); 157 $h = $h->multiply($this->coefficients[2]); 158 list(, $h) = $h->divide($this->primes[1]); 159 $m = $m_i[2]->add($h->multiply($this->primes[2])); 160 161 $r = $this->primes[1]; 162 for ($i = 3; $i <= $num_primes; $i++) { 163 $m_i = $this->blind($x, $r, $i); 164 165 $r = $r->multiply($this->primes[$i - 1]); 166 167 $h = $m_i->subtract($m); 168 $h = $h->multiply($this->coefficients[$i]); 169 list(, $h) = $h->divide($this->primes[$i]); 170 171 $m = $m->add($r->multiply($h)); 172 } 173 } 174 175 return $m; 176 } 177 178 /** 179 * Performs RSA Blinding 180 * 181 * Protects against timing attacks by employing RSA Blinding. 182 * Returns $x->modPow($this->exponents[$i], $this->primes[$i]) 183 * 184 * @access private 185 * @param \phpseclib3\Math\BigInteger $x 186 * @param \phpseclib3\Math\BigInteger $r 187 * @param int $i 188 * @return \phpseclib3\Math\BigInteger 189 */ 190 private function blind($x, $r, $i) 191 { 192 $x = $x->multiply($r->modPow($this->publicExponent, $this->primes[$i])); 193 $x = $x->modPow($this->exponents[$i], $this->primes[$i]); 194 195 $r = $r->modInverse($this->primes[$i]); 196 $x = $x->multiply($r); 197 list(, $x) = $x->divide($this->primes[$i]); 198 199 return $x; 200 } 201 202 /** 203 * EMSA-PSS-ENCODE 204 * 205 * See {@link http://tools.ietf.org/html/rfc3447#section-9.1.1 RFC3447#section-9.1.1}. 206 * 207 * @return string 208 * @access private 209 * @param string $m 210 * @throws \RuntimeException on encoding error 211 * @param int $emBits 212 */ 213 private function emsa_pss_encode($m, $emBits) 214 { 215 // if $m is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error 216 // be output. 217 218 $emLen = ($emBits + 1) >> 3; // ie. ceil($emBits / 8) 219 $sLen = $this->sLen !== null ? $this->sLen : $this->hLen; 220 221 $mHash = $this->hash->hash($m); 222 if ($emLen < $this->hLen + $sLen + 2) { 223 throw new \LengthException('RSA modulus too short'); 224 } 225 226 $salt = Random::string($sLen); 227 $m2 = "\0\0\0\0\0\0\0\0" . $mHash . $salt; 228 $h = $this->hash->hash($m2); 229 $ps = str_repeat(chr(0), $emLen - $sLen - $this->hLen - 2); 230 $db = $ps . chr(1) . $salt; 231 $dbMask = $this->mgf1($h, $emLen - $this->hLen - 1); // ie. stlren($db) 232 $maskedDB = $db ^ $dbMask; 233 $maskedDB[0] = ~chr(0xFF << ($emBits & 7)) & $maskedDB[0]; 234 $em = $maskedDB . $h . chr(0xBC); 235 236 return $em; 237 } 238 239 /** 240 * RSASSA-PSS-SIGN 241 * 242 * See {@link http://tools.ietf.org/html/rfc3447#section-8.1.1 RFC3447#section-8.1.1}. 243 * 244 * @access private 245 * @param string $m 246 * @return bool|string 247 */ 248 private function rsassa_pss_sign($m) 249 { 250 // EMSA-PSS encoding 251 252 $em = $this->emsa_pss_encode($m, 8 * $this->k - 1); 253 254 // RSA signature 255 256 $m = $this->os2ip($em); 257 $s = $this->rsasp1($m); 258 $s = $this->i2osp($s, $this->k); 259 260 // Output the signature S 261 262 return $s; 263 } 264 265 /** 266 * RSASSA-PKCS1-V1_5-SIGN 267 * 268 * See {@link http://tools.ietf.org/html/rfc3447#section-8.2.1 RFC3447#section-8.2.1}. 269 * 270 * @access private 271 * @param string $m 272 * @throws \LengthException if the RSA modulus is too short 273 * @return bool|string 274 */ 275 private function rsassa_pkcs1_v1_5_sign($m) 276 { 277 // EMSA-PKCS1-v1_5 encoding 278 279 // If the encoding operation outputs "intended encoded message length too short," output "RSA modulus 280 // too short" and stop. 281 try { 282 $em = $this->emsa_pkcs1_v1_5_encode($m, $this->k); 283 } catch (\LengthException $e) { 284 throw new \LengthException('RSA modulus too short'); 285 } 286 287 // RSA signature 288 289 $m = $this->os2ip($em); 290 $s = $this->rsasp1($m); 291 $s = $this->i2osp($s, $this->k); 292 293 // Output the signature S 294 295 return $s; 296 } 297 298 /** 299 * Create a signature 300 * 301 * @see self::verify() 302 * @access public 303 * @param string $message 304 * @return string 305 */ 306 public function sign($message) 307 { 308 switch ($this->signaturePadding) { 309 case self::SIGNATURE_PKCS1: 310 case self::SIGNATURE_RELAXED_PKCS1: 311 return $this->rsassa_pkcs1_v1_5_sign($message); 312 //case self::SIGNATURE_PSS: 313 default: 314 return $this->rsassa_pss_sign($message); 315 } 316 } 317 318 /** 319 * RSAES-PKCS1-V1_5-DECRYPT 320 * 321 * See {@link http://tools.ietf.org/html/rfc3447#section-7.2.2 RFC3447#section-7.2.2}. 322 * 323 * @access private 324 * @param string $c 325 * @return bool|string 326 */ 327 private function rsaes_pkcs1_v1_5_decrypt($c) 328 { 329 // Length checking 330 331 if (strlen($c) != $this->k) { // or if k < 11 332 throw new \LengthException('Ciphertext representative too long'); 333 } 334 335 // RSA decryption 336 337 $c = $this->os2ip($c); 338 $m = $this->rsadp($c); 339 $em = $this->i2osp($m, $this->k); 340 341 // EME-PKCS1-v1_5 decoding 342 343 if (ord($em[0]) != 0 || ord($em[1]) > 2) { 344 throw new \RuntimeException('Decryption error'); 345 } 346 347 $ps = substr($em, 2, strpos($em, chr(0), 2) - 2); 348 $m = substr($em, strlen($ps) + 3); 349 350 if (strlen($ps) < 8) { 351 throw new \RuntimeException('Decryption error'); 352 } 353 354 // Output M 355 356 return $m; 357 } 358 359 /** 360 * RSAES-OAEP-DECRYPT 361 * 362 * See {@link http://tools.ietf.org/html/rfc3447#section-7.1.2 RFC3447#section-7.1.2}. The fact that the error 363 * messages aren't distinguishable from one another hinders debugging, but, to quote from RFC3447#section-7.1.2: 364 * 365 * Note. Care must be taken to ensure that an opponent cannot 366 * distinguish the different error conditions in Step 3.g, whether by 367 * error message or timing, or, more generally, learn partial 368 * information about the encoded message EM. Otherwise an opponent may 369 * be able to obtain useful information about the decryption of the 370 * ciphertext C, leading to a chosen-ciphertext attack such as the one 371 * observed by Manger [36]. 372 * 373 * @access private 374 * @param string $c 375 * @return bool|string 376 */ 377 private function rsaes_oaep_decrypt($c) 378 { 379 // Length checking 380 381 // if $l is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error 382 // be output. 383 384 if (strlen($c) != $this->k || $this->k < 2 * $this->hLen + 2) { 385 throw new \LengthException('Ciphertext representative too long'); 386 } 387 388 // RSA decryption 389 390 $c = $this->os2ip($c); 391 $m = $this->rsadp($c); 392 $em = $this->i2osp($m, $this->k); 393 394 // EME-OAEP decoding 395 396 $lHash = $this->hash->hash($this->label); 397 $y = ord($em[0]); 398 $maskedSeed = substr($em, 1, $this->hLen); 399 $maskedDB = substr($em, $this->hLen + 1); 400 $seedMask = $this->mgf1($maskedDB, $this->hLen); 401 $seed = $maskedSeed ^ $seedMask; 402 $dbMask = $this->mgf1($seed, $this->k - $this->hLen - 1); 403 $db = $maskedDB ^ $dbMask; 404 $lHash2 = substr($db, 0, $this->hLen); 405 $m = substr($db, $this->hLen); 406 $hashesMatch = hash_equals($lHash, $lHash2); 407 $leadingZeros = 1; 408 $patternMatch = 0; 409 $offset = 0; 410 for ($i = 0; $i < strlen($m); $i++) { 411 $patternMatch |= $leadingZeros & ($m[$i] === "\1"); 412 $leadingZeros &= $m[$i] === "\0"; 413 $offset += $patternMatch ? 0 : 1; 414 } 415 416 // we do | instead of || to avoid https://en.wikipedia.org/wiki/Short-circuit_evaluation 417 // to protect against timing attacks 418 if (!$hashesMatch | !$patternMatch) { 419 throw new \RuntimeException('Decryption error'); 420 } 421 422 // Output the message M 423 424 return substr($m, $offset + 1); 425 } 426 427 /** 428 * Raw Encryption / Decryption 429 * 430 * Doesn't use padding and is not recommended. 431 * 432 * @access private 433 * @param string $m 434 * @return bool|string 435 * @throws \LengthException if strlen($m) > $this->k 436 */ 437 private function raw_encrypt($m) 438 { 439 if (strlen($m) > $this->k) { 440 throw new \LengthException('Ciphertext representative too long'); 441 } 442 443 $temp = $this->os2ip($m); 444 $temp = $this->rsadp($temp); 445 return $this->i2osp($temp, $this->k); 446 } 447 448 /** 449 * Decryption 450 * 451 * @see self::encrypt() 452 * @access public 453 * @param string $ciphertext 454 * @return bool|string 455 */ 456 public function decrypt($ciphertext) 457 { 458 switch ($this->encryptionPadding) { 459 case self::ENCRYPTION_NONE: 460 return $this->raw_encrypt($ciphertext); 461 case self::ENCRYPTION_PKCS1: 462 return $this->rsaes_pkcs1_v1_5_decrypt($ciphertext); 463 //case self::ENCRYPTION_OAEP: 464 default: 465 return $this->rsaes_oaep_decrypt($ciphertext); 466 } 467 } 468 469 /** 470 * Returns the public key 471 * 472 * @access public 473 * @return mixed 474 */ 475 public function getPublicKey() 476 { 477 $type = self::validatePlugin('Keys', 'PKCS8', 'savePublicKey'); 478 if (empty($this->modulus) || empty($this->publicExponent)) { 479 throw new \RuntimeException('Public key components not found'); 480 } 481 482 $key = $type::savePublicKey($this->modulus, $this->publicExponent); 483 return RSA::loadFormat('PKCS8', $key) 484 ->withHash($this->hash->getHash()) 485 ->withMGFHash($this->mgfHash->getHash()) 486 ->withSaltLength($this->sLen) 487 ->withLabel($this->label) 488 ->withPadding($this->signaturePadding | $this->encryptionPadding); 489 } 490 491 /** 492 * Returns the private key 493 * 494 * @param string $type 495 * @param array $options optional 496 * @return string 497 */ 498 public function toString($type, array $options = []) 499 { 500 $type = self::validatePlugin( 501 'Keys', 502 $type, 503 empty($this->primes) ? 'savePublicKey' : 'savePrivateKey' 504 ); 505 506 if ($type == PSS::class) { 507 if ($this->signaturePadding == self::SIGNATURE_PSS) { 508 $options += [ 509 'hash' => $this->hash->getHash(), 510 'MGFHash' => $this->mgfHash->getHash(), 511 'saltLength' => $this->getSaltLength() 512 ]; 513 } else { 514 throw new UnsupportedFormatException('The PSS format can only be used when the signature method has been explicitly set to PSS'); 515 } 516 } 517 518 if (empty($this->primes)) { 519 return $type::savePublicKey($this->modulus, $this->exponent, $options); 520 } 521 522 return $type::savePrivateKey($this->modulus, $this->publicExponent, $this->exponent, $this->primes, $this->exponents, $this->coefficients, $this->password, $options); 523 524 /* 525 $key = $type::savePrivateKey($this->modulus, $this->publicExponent, $this->exponent, $this->primes, $this->exponents, $this->coefficients, $this->password, $options); 526 if ($key !== false || count($this->primes) == 2) { 527 return $key; 528 } 529 530 $nSize = $this->getSize() >> 1; 531 532 $primes = [1 => clone self::$one, clone self::$one]; 533 $i = 1; 534 foreach ($this->primes as $prime) { 535 $primes[$i] = $primes[$i]->multiply($prime); 536 if ($primes[$i]->getLength() >= $nSize) { 537 $i++; 538 } 539 } 540 541 $exponents = []; 542 $coefficients = [2 => $primes[2]->modInverse($primes[1])]; 543 544 foreach ($primes as $i => $prime) { 545 $temp = $prime->subtract(self::$one); 546 $exponents[$i] = $this->modulus->modInverse($temp); 547 } 548 549 return $type::savePrivateKey($this->modulus, $this->publicExponent, $this->exponent, $primes, $exponents, $coefficients, $this->password, $options); 550 */ 551 } 552} 553