sop / gcm

lib/GCM/GCM.php

Indentation +248 added lines, -248 removed lines

@@ -14,267 +14,267 @@
  */
 class GCM
 {
-    /**
-     * Block of 64 zero bits.
-     *
-     * @var string
-     */
-    const ZB_64 = "\0\0\0\0\0\0\0\0";
+	/**
+	 * Block of 64 zero bits.
+	 *
+	 * @var string
+	 */
+	const ZB_64 = "\0\0\0\0\0\0\0\0";
     
-    /**
-     * Block of 128 zero bits.
-     *
-     * @var string
-     */
-    const ZB_128 = self::ZB_64 . self::ZB_64;
+	/**
+	 * Block of 128 zero bits.
+	 *
+	 * @var string
+	 */
+	const ZB_128 = self::ZB_64 . self::ZB_64;
     
-    /**
-     * Array of supported t-values, that is, the bit length of the
-     * authentication tag.
-     *
-     * See NIST SP-800-38D section 5.2.1.2 for the details.
-     *
-     * @internal
-     *
-     * @var array
-     */
-    const SUPPORTED_T_LEN = array(128, 120, 112, 104, 96, 64, 32);
+	/**
+	 * Array of supported t-values, that is, the bit length of the
+	 * authentication tag.
+	 *
+	 * See NIST SP-800-38D section 5.2.1.2 for the details.
+	 *
+	 * @internal
+	 *
+	 * @var array
+	 */
+	const SUPPORTED_T_LEN = array(128, 120, 112, 104, 96, 64, 32);
     
-    /**
-     * Cipher.
-     *
-     * @var Cipher $_cipher
-     */
-    protected $_cipher;
+	/**
+	 * Cipher.
+	 *
+	 * @var Cipher $_cipher
+	 */
+	protected $_cipher;
     
-    /**
-     * Authentication tag length in bytes.
-     *
-     * @var int
-     */
-    protected $_tagLength;
+	/**
+	 * Authentication tag length in bytes.
+	 *
+	 * @var int
+	 */
+	protected $_tagLength;
     
-    /**
-     * Constructor.
-     *
-     * @param Cipher $cipher Cipher implementation
-     * @param int $tag_length Authentication tag length in bytes
-     * @throws \DomainException If tag length is not supported
-     */
-    public function __construct(Cipher $cipher, $tag_length = 16)
-    {
-        if (!in_array($tag_length << 3, self::SUPPORTED_T_LEN)) {
-            throw new \DomainException(
-                "Tag length $tag_length is not supported.");
-        }
-        $this->_cipher = $cipher;
-        $this->_tagLength = $tag_length;
-    }
+	/**
+	 * Constructor.
+	 *
+	 * @param Cipher $cipher Cipher implementation
+	 * @param int $tag_length Authentication tag length in bytes
+	 * @throws \DomainException If tag length is not supported
+	 */
+	public function __construct(Cipher $cipher, $tag_length = 16)
+	{
+		if (!in_array($tag_length << 3, self::SUPPORTED_T_LEN)) {
+			throw new \DomainException(
+				"Tag length $tag_length is not supported.");
+		}
+		$this->_cipher = $cipher;
+		$this->_tagLength = $tag_length;
+	}
     
-    /**
-     * Encrypt plaintext.
-     *
-     * @param string $P Plaintext
-     * @param string $A Additional authenticated data
-     * @param string $K Encryption key
-     * @param string $IV Initialization vector
-     * @throws \RuntimeException For generic errors
-     * @return array Tuple of ciphertext <code>C</code> and authentication tag
-     *         <code>T</code>
-     */
-    public function encrypt($P, $A, $K, $IV)
-    {
-        $ghash = new GHASH($this->_cipher->encrypt(self::ZB_128, $K));
-        // generate pre-counter block
-        $J0 = $this->_generateJ0($IV, $ghash);
-        // encrypt
-        $C = $this->_gctr(self::_inc32($J0), $P, $K);
-        // generate authentication tag
-        $T = $this->_computeAuthTag($A, $C, $J0, $K, $ghash);
-        return [$C, $T];
-    }
+	/**
+	 * Encrypt plaintext.
+	 *
+	 * @param string $P Plaintext
+	 * @param string $A Additional authenticated data
+	 * @param string $K Encryption key
+	 * @param string $IV Initialization vector
+	 * @throws \RuntimeException For generic errors
+	 * @return array Tuple of ciphertext <code>C</code> and authentication tag
+	 *         <code>T</code>
+	 */
+	public function encrypt($P, $A, $K, $IV)
+	{
+		$ghash = new GHASH($this->_cipher->encrypt(self::ZB_128, $K));
+		// generate pre-counter block
+		$J0 = $this->_generateJ0($IV, $ghash);
+		// encrypt
+		$C = $this->_gctr(self::_inc32($J0), $P, $K);
+		// generate authentication tag
+		$T = $this->_computeAuthTag($A, $C, $J0, $K, $ghash);
+		return [$C, $T];
+	}
     
-    /**
-     * Decrypt ciphertext.
-     *
-     * @param string $C Ciphertext
-     * @param string $T Authentication tag
-     * @param string $A Additional authenticated data
-     * @param string $K Encryption key
-     * @param string $IV Initialization vector
-     * @throws AuthenticationException If message authentication fails
-     * @throws \RuntimeException For generic errors
-     * @return string Plaintext <code>P</code>
-     */
-    public function decrypt($C, $T, $A, $K, $IV)
-    {
-        $ghash = new GHASH($this->_cipher->encrypt(self::ZB_128, $K));
-        // generate pre-counter block
-        $J0 = $this->_generateJ0($IV, $ghash);
-        // generate authentication tag
-        $T2 = $this->_computeAuthTag($A, $C, $J0, $K, $ghash);
-        // check that authentication tag matches
-        if ($T !== $T2) {
-            throw new AuthenticationException("Authentication failed.");
-        }
-        // decrypt
-        return $this->_gctr(self::_inc32($J0), $C, $K);
-    }
+	/**
+	 * Decrypt ciphertext.
+	 *
+	 * @param string $C Ciphertext
+	 * @param string $T Authentication tag
+	 * @param string $A Additional authenticated data
+	 * @param string $K Encryption key
+	 * @param string $IV Initialization vector
+	 * @throws AuthenticationException If message authentication fails
+	 * @throws \RuntimeException For generic errors
+	 * @return string Plaintext <code>P</code>
+	 */
+	public function decrypt($C, $T, $A, $K, $IV)
+	{
+		$ghash = new GHASH($this->_cipher->encrypt(self::ZB_128, $K));
+		// generate pre-counter block
+		$J0 = $this->_generateJ0($IV, $ghash);
+		// generate authentication tag
+		$T2 = $this->_computeAuthTag($A, $C, $J0, $K, $ghash);
+		// check that authentication tag matches
+		if ($T !== $T2) {
+			throw new AuthenticationException("Authentication failed.");
+		}
+		// decrypt
+		return $this->_gctr(self::_inc32($J0), $C, $K);
+	}
     
-    /**
-     * Generate pre-counter block.
-     *
-     * See NIST SP-300-38D section 7.1 step 2 for the details.
-     *
-     * @param string $IV Initialization vector
-     * @param GHASH $ghash GHASH functor
-     * @return string
-     */
-    private function _generateJ0($IV, GHASH $ghash)
-    {
-        // if len(IV) = 96
-        if (12 == strlen($IV)) {
-            return $IV . "\0\0\0\1";
-        }
-        $data = self::_pad128($IV) . self::ZB_64 . self::_uint64(
-            strlen($IV) << 3);
-        return $ghash($data);
-    }
+	/**
+	 * Generate pre-counter block.
+	 *
+	 * See NIST SP-300-38D section 7.1 step 2 for the details.
+	 *
+	 * @param string $IV Initialization vector
+	 * @param GHASH $ghash GHASH functor
+	 * @return string
+	 */
+	private function _generateJ0($IV, GHASH $ghash)
+	{
+		// if len(IV) = 96
+		if (12 == strlen($IV)) {
+			return $IV . "\0\0\0\1";
+		}
+		$data = self::_pad128($IV) . self::ZB_64 . self::_uint64(
+			strlen($IV) << 3);
+		return $ghash($data);
+	}
     
-    /**
-     * Apply GCTR algorithm.
-     *
-     * See NIST SP-300-38D section 6.5 for the details.
-     *
-     * @param string $ICB Initial counter block
-     * @param string $X Input data
-     * @param string $K Encryption key
-     * @return string Output data
-     */
-    private function _gctr($ICB, $X, $K)
-    {
-        // if data is an empty string, return an empty string
-        if ("" == $X) {
-            return "";
-        }
-        // number of blocks
-        $n = ceil(strlen($X) / 16);
-        $CB = $ICB;
-        $Y = "";
-        for ($i = 0; $i < $n - 1; ++$i) {
-            // plaintext block
-            $xi = substr($X, $i << 4, 16);
-            // encrypt block and append to Y
-            $Y .= $xi ^ $this->_cipher->encrypt($CB, $K);
-            // increment counter block
-            $CB = self::_inc32($CB);
-        }
-        // final block
-        $xn = substr($X, $i << 4);
-        // XOR against partial block
-        $Y .= $xn ^ substr($this->_cipher->encrypt($CB, $K), 0, strlen($xn));
-        return $Y;
-    }
+	/**
+	 * Apply GCTR algorithm.
+	 *
+	 * See NIST SP-300-38D section 6.5 for the details.
+	 *
+	 * @param string $ICB Initial counter block
+	 * @param string $X Input data
+	 * @param string $K Encryption key
+	 * @return string Output data
+	 */
+	private function _gctr($ICB, $X, $K)
+	{
+		// if data is an empty string, return an empty string
+		if ("" == $X) {
+			return "";
+		}
+		// number of blocks
+		$n = ceil(strlen($X) / 16);
+		$CB = $ICB;
+		$Y = "";
+		for ($i = 0; $i < $n - 1; ++$i) {
+			// plaintext block
+			$xi = substr($X, $i << 4, 16);
+			// encrypt block and append to Y
+			$Y .= $xi ^ $this->_cipher->encrypt($CB, $K);
+			// increment counter block
+			$CB = self::_inc32($CB);
+		}
+		// final block
+		$xn = substr($X, $i << 4);
+		// XOR against partial block
+		$Y .= $xn ^ substr($this->_cipher->encrypt($CB, $K), 0, strlen($xn));
+		return $Y;
+	}
     
-    /**
-     * Compute authentication tag
-     *
-     * See NIST SP-300-38D section 7.1 steps 5-6 for the details.
-     *
-     * @param string $A Additional authenticated data
-     * @param string $C Ciphertext
-     * @param string $J0 Pre-counter block
-     * @param string $K Encryption key
-     * @param GHASH $ghash GHASH functor
-     * @return string Authentication tag <code>T</code>
-     */
-    private function _computeAuthTag($A, $C, $J0, $K, GHASH $ghash)
-    {
-        $data = self::_pad128($A) . self::_pad128($C) .
-             self::_uint64(strlen($A) << 3) . self::_uint64(strlen($C) << 3);
-        $S = $ghash($data);
-        return substr($this->_gctr($J0, $S, $K), 0, $this->_tagLength);
-    }
+	/**
+	 * Compute authentication tag
+	 *
+	 * See NIST SP-300-38D section 7.1 steps 5-6 for the details.
+	 *
+	 * @param string $A Additional authenticated data
+	 * @param string $C Ciphertext
+	 * @param string $J0 Pre-counter block
+	 * @param string $K Encryption key
+	 * @param GHASH $ghash GHASH functor
+	 * @return string Authentication tag <code>T</code>
+	 */
+	private function _computeAuthTag($A, $C, $J0, $K, GHASH $ghash)
+	{
+		$data = self::_pad128($A) . self::_pad128($C) .
+			 self::_uint64(strlen($A) << 3) . self::_uint64(strlen($C) << 3);
+		$S = $ghash($data);
+		return substr($this->_gctr($J0, $S, $K), 0, $this->_tagLength);
+	}
     
-    /**
-     * Pad data to 128 bit block boundary.
-     *
-     * @param string $data
-     * @return string
-     */
-    private static function _pad128($data)
-    {
-        $padlen = 16 - strlen($data) % 16;
-        if (16 != $padlen) {
-            $data .= str_repeat("\0", $padlen);
-        }
-        return $data;
-    }
+	/**
+	 * Pad data to 128 bit block boundary.
+	 *
+	 * @param string $data
+	 * @return string
+	 */
+	private static function _pad128($data)
+	{
+		$padlen = 16 - strlen($data) % 16;
+		if (16 != $padlen) {
+			$data .= str_repeat("\0", $padlen);
+		}
+		return $data;
+	}
     
-    /**
-     * Increment 32 rightmost bits of the counter block.
-     *
-     * See NIST SP-300-38D section 6.2 for the details.
-     *
-     * @param string $X
-     * @return string
-     */
-    private static function _inc32($X)
-    {
-        $Y = substr($X, 0, -4);
-        // increment counter
-        $n = self::strToGMP(substr($X, -4)) + 1;
-        // wrap by using only the 32 rightmost bits
-        $Y .= substr(self::gmpToStr($n, 4), -4);
-        return $Y;
-    }
+	/**
+	 * Increment 32 rightmost bits of the counter block.
+	 *
+	 * See NIST SP-300-38D section 6.2 for the details.
+	 *
+	 * @param string $X
+	 * @return string
+	 */
+	private static function _inc32($X)
+	{
+		$Y = substr($X, 0, -4);
+		// increment counter
+		$n = self::strToGMP(substr($X, -4)) + 1;
+		// wrap by using only the 32 rightmost bits
+		$Y .= substr(self::gmpToStr($n, 4), -4);
+		return $Y;
+	}
     
-    /**
-     * Convert integer to 64 bit big endian binary string.
-     *
-     * @param int $num
-     * @return string
-     */
-    private static function _uint64($num)
-    {
-        // truncate on 32 bit hosts
-        if (PHP_INT_SIZE < 8) {
-            return "\0\0\0\0" . pack("N", $num);
-        }
-        return pack("J", $num);
-    }
+	/**
+	 * Convert integer to 64 bit big endian binary string.
+	 *
+	 * @param int $num
+	 * @return string
+	 */
+	private static function _uint64($num)
+	{
+		// truncate on 32 bit hosts
+		if (PHP_INT_SIZE < 8) {
+			return "\0\0\0\0" . pack("N", $num);
+		}
+		return pack("J", $num);
+	}
     
-    /**
-     * Convert string to GMP number.
-     *
-     * String is interpreted as an unsigned integer with big endian order and
-     * the most significant byte first.
-     *
-     * @param string $data Binary data
-     * @return \GMP
-     */
-    public static function strToGMP($data)
-    {
-        return gmp_import($data, 1, GMP_MSW_FIRST | GMP_BIG_ENDIAN);
-    }
+	/**
+	 * Convert string to GMP number.
+	 *
+	 * String is interpreted as an unsigned integer with big endian order and
+	 * the most significant byte first.
+	 *
+	 * @param string $data Binary data
+	 * @return \GMP
+	 */
+	public static function strToGMP($data)
+	{
+		return gmp_import($data, 1, GMP_MSW_FIRST | GMP_BIG_ENDIAN);
+	}
     
-    /**
-     * Convert GMP number to string.
-     *
-     * Returned string represents an unsigned integer with big endian order and
-     * the most significant byte first.
-     *
-     * @param \GMP $num GMP number
-     * @param int $size Width of the string in bytes
-     * @return string Binary data
-     */
-    public static function gmpToStr(\GMP $num, $size)
-    {
-        $data = gmp_export($num, 1, GMP_MSW_FIRST | GMP_BIG_ENDIAN);
-        $len = strlen($data);
-        if ($len < $size) {
-            $data = str_repeat("\0", $size - $len) . $data;
-        }
-        return $data;
-    }
+	/**
+	 * Convert GMP number to string.
+	 *
+	 * Returned string represents an unsigned integer with big endian order and
+	 * the most significant byte first.
+	 *
+	 * @param \GMP $num GMP number
+	 * @param int $size Width of the string in bytes
+	 * @return string Binary data
+	 */
+	public static function gmpToStr(\GMP $num, $size)
+	{
+		$data = gmp_export($num, 1, GMP_MSW_FIRST | GMP_BIG_ENDIAN);
+		$len = strlen($data);
+		if ($len < $size) {
+			$data = str_repeat("\0", $size - $len) . $data;
+		}
+		return $data;
+	}
 }

lib/GCM/GHASH.php

Indentation +85 added lines, -85 removed lines

@@ -11,94 +11,94 @@
  */
 class GHASH
 {
-    /**
-     * Fixed R-block.
-     *
-     * @var string
-     */
-    const R = "\xE1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
+	/**
+	 * Fixed R-block.
+	 *
+	 * @var string
+	 */
+	const R = "\xE1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
     
-    /**
-     * Hash subkey.
-     *
-     * @var string $_subkey
-     */
-    protected $_subkey;
+	/**
+	 * Hash subkey.
+	 *
+	 * @var string $_subkey
+	 */
+	protected $_subkey;
     
-    /**
-     * Constructor.
-     *
-     * @param string $subkey Hash subkey
-     */
-    public function __construct($subkey)
-    {
-        if (strlen($subkey) != 16) {
-            throw new \LengthException("Subkey must be 128 bits.");
-        }
-        $this->_subkey = $subkey;
-    }
+	/**
+	 * Constructor.
+	 *
+	 * @param string $subkey Hash subkey
+	 */
+	public function __construct($subkey)
+	{
+		if (strlen($subkey) != 16) {
+			throw new \LengthException("Subkey must be 128 bits.");
+		}
+		$this->_subkey = $subkey;
+	}
     
-    /**
-     * Compute hash.
-     *
-     * @param string $X Input string
-     * @return string Hash
-     */
-    public function compute($X)
-    {
-        $len = strlen($X);
-        if (0 != $len % 16) {
-            throw new \UnexpectedValueException(
-                "Input string must be a multiple of 128 bits.");
-        }
-        $Y = GCM::ZB_128;
-        // number of 128-bit blocks
-        $m = $len >> 4;
-        for ($i = 0; $i < $m; ++$i) {
-            $xi = substr($X, $i << 4, 16);
-            $Y = $this->_mult($Y ^ $xi, $this->_subkey);
-        }
-        return $Y;
-    }
+	/**
+	 * Compute hash.
+	 *
+	 * @param string $X Input string
+	 * @return string Hash
+	 */
+	public function compute($X)
+	{
+		$len = strlen($X);
+		if (0 != $len % 16) {
+			throw new \UnexpectedValueException(
+				"Input string must be a multiple of 128 bits.");
+		}
+		$Y = GCM::ZB_128;
+		// number of 128-bit blocks
+		$m = $len >> 4;
+		for ($i = 0; $i < $m; ++$i) {
+			$xi = substr($X, $i << 4, 16);
+			$Y = $this->_mult($Y ^ $xi, $this->_subkey);
+		}
+		return $Y;
+	}
     
-    /**
-     * Functor method for <code>compute</code>.
-     *
-     * @param string $arg
-     * @return string
-     */
-    public function __invoke($arg)
-    {
-        return $this->compute($arg);
-    }
+	/**
+	 * Functor method for <code>compute</code>.
+	 *
+	 * @param string $arg
+	 * @return string
+	 */
+	public function __invoke($arg)
+	{
+		return $this->compute($arg);
+	}
     
-    /**
-     * Apply block multiplication operation.
-     *
-     * See NIST SP-800-38D, chapter 6.3 for the details.
-     *
-     * @param string $X
-     * @param string $Y
-     * @return string
-     */
-    private function _mult($X, $Y)
-    {
-        $x = GCM::strToGMP($X);
-        $Z = GCM::strToGMP(GCM::ZB_128);
-        $V = GCM::strToGMP($Y);
-        $R = GCM::strToGMP(self::R);
-        for ($i = 0; $i < 128; ++$i) {
-            // if bit at X[i] is set
-            if (gmp_testbit($x, 127 - $i)) {
-                $Z ^= $V;
-            }
-            // if LSB(Vi) = 0
-            if (!gmp_testbit($V, 0)) {
-                $V >>= 1;
-            } else {
-                $V = ($V >> 1) ^ $R;
-            }
-        }
-        return GCM::gmpToStr($Z, 16);
-    }
+	/**
+	 * Apply block multiplication operation.
+	 *
+	 * See NIST SP-800-38D, chapter 6.3 for the details.
+	 *
+	 * @param string $X
+	 * @param string $Y
+	 * @return string
+	 */
+	private function _mult($X, $Y)
+	{
+		$x = GCM::strToGMP($X);
+		$Z = GCM::strToGMP(GCM::ZB_128);
+		$V = GCM::strToGMP($Y);
+		$R = GCM::strToGMP(self::R);
+		for ($i = 0; $i < 128; ++$i) {
+			// if bit at X[i] is set
+			if (gmp_testbit($x, 127 - $i)) {
+				$Z ^= $V;
+			}
+			// if LSB(Vi) = 0
+			if (!gmp_testbit($V, 0)) {
+				$V >>= 1;
+			} else {
+				$V = ($V >> 1) ^ $R;
+			}
+		}
+		return GCM::gmpToStr($Z, 16);
+	}
 }