AESGCM::getHash() - Code Metrics - Inspection of "Doc added" - Spomky-Labs/php-aes-gcm - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( a69544...c28e38 )

by Florent

created 2016-04-28 13:35 UTC

AESGCM::getHash() A

↳ Parent: AESGCM

Complexity

Conditions	2
Paths	2

Size

Total Lines	11
Code Lines	7

Duplication

Lines	0
Ratio	0 %

Metric	Value
dl	0
loc	11
rs	9.4285
cc	2
eloc	7
nc	2
nop	2

<?php

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2016 Spomky-Labs
 *
 * This software may be modified and distributed under the terms
 * of the MIT license.  See the LICENSE file for details.
 */

namespace AESGCM;

use Assert\Assertion;

final class AESGCM
{
    /**
     * @param string $K  Key encryption key
     * @param string $IV Initialization vector
     * @param string $P  Data to encrypt
     * @param string $A  Additional Authentication Data
     *
     * @return array
     */
    public static function encrypt($K, $IV, $P, $A)
    {
        list($J0, $v, $a_len_padding, $H) = self::common($K, $IV, $A);

        $C = self::getGCTR($K, self::getInc(32, $J0), $P);
        $u = self::calcVector($C);
        $c_len_padding = self::addPadding($C);

        $S = self::getHash($H, $A.str_pad('', $v / 8, "\0").$C.str_pad('', $u / 8, "\0").$a_len_padding.$c_len_padding);
        $T = self::getMSB(128, self::getGCTR($K, $J0, $S));

        return [$C, $T];
    }

    /**
     * @param string $K  Key encryption key
     * @param string $IV Initialization vector
     * @param string $C  Data to encrypt
     * @param string $A  Additional Authentication Data
     * @param string $T  Tag
     *
     * @return array
     */
    public static function decrypt($K, $IV, $C, $A, $T)
    {
        list($J0, $v, $a_len_padding, $H) = self::common($K, $IV, $A);

        $P = self::getGCTR($K, self::getInc(32, $J0), $C);

        $u = self::calcVector($C);
        $c_len_padding = self::addPadding($C);

        $S = self::getHash($H, $A.str_pad('', $v / 8, "\0").$C.str_pad('', $u / 8, "\0").$a_len_padding.$c_len_padding);
        $T1 = self::getMSB(self::getLength($T), self::getGCTR($K, $J0, $S));
        $result = strcmp($T, $T1);
        Assertion::eq($result, 0, 'Unable to decrypt or to verify the tag.');

        return $P;
    }

    /**
     * @param $K
     * @param $IV
     * @param $A
     *
     * @return array
     */
    private static function common($K, $IV, $A)
    {
        $key_length = mb_strlen($K, '8bit') * 8;
        Assertion::inArray($key_length, [128, 192, 256], 'Bad key length.');

        $H = openssl_encrypt(str_repeat("\0", 16), 'aes-'.($key_length).'-ecb', $K, OPENSSL_NO_PADDING | OPENSSL_RAW_DATA); //---
        $iv_len = self::getLength($IV);

        if ($iv_len == 96) {
            $J0 = $IV.pack('H*', '00000001');
        } else {
            $s = self::calcVector($IV);
            Assertion::eq(($s + 64) % 8, 0, 'Unable to decrypt or to verify the tag.');

            $packed_iv_len = pack('N', $iv_len);
            $iv_len_padding = str_pad($packed_iv_len, 8, "\0", STR_PAD_LEFT);
            $hash_X = $IV.str_pad('', ($s + 64) / 8, "\0").$iv_len_padding;
            $J0 = self::getHash($H, $hash_X);
        }
        $v = self::calcVector($A);
        $a_len_padding = self::addPadding($A);

        return [$J0, $v, $a_len_padding, $H];
    }

    /**
     * @param string $value
     *
     * @return int
     */
    private static function calcVector($value)
    {
        return (128 * ceil(self::getLength($value) / 128)) - self::getLength($value);
    }

    /**
     * @param string $value
     *
     * @return string
     */
    private static function addPadding($value)
    {
        return str_pad(pack('N', self::getLength($value)), 8, "\0", STR_PAD_LEFT);
    }

    /**
     * @param string $x
     *
     * @return int
     */
    private static function getLength($x)
    {
        return mb_strlen($x, '8bit') * 8;
    }

    /**
     * @param int $num_bits
     * @param int $x
     *
     * @return string
     */
    private static function getMSB($num_bits, $x)
    {
        $num_bytes = $num_bits / 8;

        return mb_substr($x, 0, $num_bytes, '8bit');
    }

    /**
     * @param int $num_bits
     * @param int $x
     *
     * @return string
     */
    private static function getLSB($num_bits, $x)
    {
        $num_bytes = ($num_bits / 8);

        return mb_substr($x, -$num_bytes, null, '8bit');
    }

    /**
     * @param int $s_bits
     * @param int $x
     *
     * @return string
     */
    private static function getInc($s_bits, $x)
    {
        $lsb = self::getLSB($s_bits, $x);
        $X = self::toUInt32Bits($lsb) + 1;
        $res = self::getMSB(self::getLength($x) - $s_bits, $x).pack('N', $X);

        return $res;
    }

    /**
     * @param string $bin
     *
     * @return mixed
     */
    private static function toUInt32Bits($bin)
    {
        // $bin is the binary 32-bit BE string that represents the integer
        $int_size = 4;
        if ($int_size <= 4) {
            list(, $h, $l) = unpack('n*', $bin);

            return $l + ($h * 0x010000);
        } else {
            list(, $int) = unpack('N', $bin);

            return $int;
        }
    }

    /**
     * @param $X
     * @param $Y
     *
     * @return string
     */
    private static function getProduct($X, $Y)
    {
        $R = pack('H*', 'E1').str_pad('', 15, "\0");
        $Z = str_pad('', 16, "\0");
        $V = $Y;

        $parts = str_split($X, 4);
        $x = sprintf('%032b%032b%032b%032b', self::toUInt32Bits($parts[0]), self::toUInt32Bits($parts[1]), self::toUInt32Bits($parts[2]), self::toUInt32Bits($parts[3]));
        $lsb_mask = "\1";
        for ($i = 0; $i < 128; $i++) {
            if ($x[$i]) {
                $Z = self::getBitXor($Z, $V);
            }
            $lsb_8 = mb_substr($V, -1, null, '8bit');
            if (ord($lsb_8 & $lsb_mask)) {
                $V = self::getBitXor(self::shiftStringToRight($V), $R);
            } else {
                $V = self::shiftStringToRight($V);
            }
        }

        return $Z;
    }

    /**
     * @param string $input
     *
     * @return string
     */
    private static function shiftStringToRight($input)
    {
        $width = 4;
        $parts = array_map('self::toUInt32Bits', str_split($input, $width));
        $runs = count($parts);

        for ($i = $runs - 1; $i >= 0; $i--) {
            if ($i) {
                $lsb1 = $parts[$i - 1] & 0x00000001;
                if ($lsb1) {
                    $parts[$i] = ($parts[$i] >> 1) | 0x80000000;
                    $parts[$i] = pack('N', $parts[$i]);
                    continue;
                }
            }
            $parts[$i] = ($parts[$i] >> 1) & 0x7FFFFFFF; // get rid of sign bit
            $parts[$i] = pack('N', $parts[$i]);
        }
        $res = implode('', $parts);

        return $res;
    }

    /**
     * @param string $H
     * @param string $X
     *
     * @return mixed
     */
    private static function getHash($H, $X)
    {
        $Y = [];
        $Y[0] = str_pad('', 16, "\0");
        $num_blocks = (int) (mb_strlen($X, '8bit') / 16);
        for ($i = 1; $i <= $num_blocks; $i++) {
            $Y[$i] = self::getProduct(self::getBitXor($Y[$i - 1], mb_substr($X, ($i - 1) * 16, 16, '8bit')), $H);
        }

        return $Y[$num_blocks];
    }

    /**
     * @param string $K
     * @param string $ICB
     * @param string $X
     *
     * @return string
     */
    private static function getGCTR($K, $ICB, $X)
    {
        if ($X == '') {
            return '';
        }

        $n = (int) ceil(self::getLength($X) / 128);
        $CB = [];
        $Y = [];
        $CB[1] = $ICB;
        for ($i = 2; $i <= $n; $i++) {
            $CB[$i] = self::getInc(32, $CB[$i - 1]);
        }
        $key_length = strlen($K) * 8;
        $mode = 'aes-'.($key_length).'-ecb';
        for ($i = 1; $i < $n; $i++) {
            $C = openssl_encrypt($CB[$i], $mode, $K, OPENSSL_NO_PADDING | OPENSSL_RAW_DATA);
            $Y[$i] = self::getBitXor(mb_substr($X, ($i - 1) * 16, 16, '8bit'), $C);
        }

        $Xn = mb_substr($X, ($n - 1) * 16, null, '8bit');
        $C = openssl_encrypt($CB[$n], $mode, $K, OPENSSL_NO_PADDING | OPENSSL_RAW_DATA);
        $Y[$n] = self::getBitXor($Xn, self::getMSB(self::getLength($Xn), $C));

        return implode('', $Y);
    }

    /**
     * @param string $o1
     * @param string $o2
     *
     * @return string
     */
    private static function getBitXor($o1, $o2)
    {
        $xorWidth = PHP_INT_SIZE;
        $o1 = str_split($o1, $xorWidth);
        $o2 = str_split($o2, $xorWidth);
        $res = '';
        $runs = count($o1);
        for ($i = 0; $i < $runs; $i++) {
            $res .= $o1[$i] ^ $o2[$i];
        }

        return $res;
    }
}


1			<?php
2
3			/*
4			* The MIT License (MIT)
5			*
6			* Copyright (c) 2016 Spomky-Labs
7			*
8			* This software may be modified and distributed under the terms
9			* of the MIT license. See the LICENSE file for details.
10			*/
11
12			namespace AESGCM;
13
14			use Assert\Assertion;
15
16			final class AESGCM
17			{
18			/**
19			* @param string $K Key encryption key
20			* @param string $IV Initialization vector
21			* @param string $P Data to encrypt
22			* @param string $A Additional Authentication Data
23			*
24			* @return array
25			*/
26			public static function encrypt($K, $IV, $P, $A)
27			{
28			list($J0, $v, $a_len_padding, $H) = self::common($K, $IV, $A);
29
30			$C = self::getGCTR($K, self::getInc(32, $J0), $P);
31			$u = self::calcVector($C);
32			$c_len_padding = self::addPadding($C);
33
34			$S = self::getHash($H, $A.str_pad('', $v / 8, "\0").$C.str_pad('', $u / 8, "\0").$a_len_padding.$c_len_padding);
35			$T = self::getMSB(128, self::getGCTR($K, $J0, $S));
36
37			return [$C, $T];
38			}
39
40			/**
41			* @param string $K Key encryption key
42			* @param string $IV Initialization vector
43			* @param string $C Data to encrypt
44			* @param string $A Additional Authentication Data
45			* @param string $T Tag
46			*
47			* @return array
48			*/
49			public static function decrypt($K, $IV, $C, $A, $T)
50			{
51			list($J0, $v, $a_len_padding, $H) = self::common($K, $IV, $A);
52
53			$P = self::getGCTR($K, self::getInc(32, $J0), $C);
54
55			$u = self::calcVector($C);
56			$c_len_padding = self::addPadding($C);
57
58			$S = self::getHash($H, $A.str_pad('', $v / 8, "\0").$C.str_pad('', $u / 8, "\0").$a_len_padding.$c_len_padding);
59			$T1 = self::getMSB(self::getLength($T), self::getGCTR($K, $J0, $S));
60			$result = strcmp($T, $T1);
61			Assertion::eq($result, 0, 'Unable to decrypt or to verify the tag.');
62
63			return $P;
64			}
65
66			/**
67			* @param $K
68			* @param $IV
69			* @param $A
70			*
71			* @return array
72			*/
73			private static function common($K, $IV, $A)
74			{
75			$key_length = mb_strlen($K, '8bit') * 8;
76			Assertion::inArray($key_length, [128, 192, 256], 'Bad key length.');
77
78			$H = openssl_encrypt(str_repeat("\0", 16), 'aes-'.($key_length).'-ecb', $K, OPENSSL_NO_PADDING \| OPENSSL_RAW_DATA); //---
79			$iv_len = self::getLength($IV);
80
81			if ($iv_len == 96) {
82			$J0 = $IV.pack('H*', '00000001');
83			} else {
84			$s = self::calcVector($IV);
85			Assertion::eq(($s + 64) % 8, 0, 'Unable to decrypt or to verify the tag.');
86
87			$packed_iv_len = pack('N', $iv_len);
88			$iv_len_padding = str_pad($packed_iv_len, 8, "\0", STR_PAD_LEFT);
89			$hash_X = $IV.str_pad('', ($s + 64) / 8, "\0").$iv_len_padding;
90			$J0 = self::getHash($H, $hash_X);
91			}
92			$v = self::calcVector($A);
93			$a_len_padding = self::addPadding($A);
94
95			return [$J0, $v, $a_len_padding, $H];
96			}
97
98			/**
99			* @param string $value
100			*
101			* @return int
102			*/
103			private static function calcVector($value)
104			{
105			return (128 * ceil(self::getLength($value) / 128)) - self::getLength($value);
106			}
107
108			/**
109			* @param string $value
110			*
111			* @return string
112			*/
113			private static function addPadding($value)
114			{
115			return str_pad(pack('N', self::getLength($value)), 8, "\0", STR_PAD_LEFT);
116			}
117
118			/**
119			* @param string $x
120			*
121			* @return int
122			*/
123			private static function getLength($x)
124			{
125			return mb_strlen($x, '8bit') * 8;
126			}
127
128			/**
129			* @param int $num_bits
130			* @param int $x
131			*
132			* @return string
133			*/
134			private static function getMSB($num_bits, $x)
135			{
136			$num_bytes = $num_bits / 8;
137
138			return mb_substr($x, 0, $num_bytes, '8bit');
139			}
140
141			/**
142			* @param int $num_bits
143			* @param int $x
144			*
145			* @return string
146			*/
147			private static function getLSB($num_bits, $x)
148			{
149			$num_bytes = ($num_bits / 8);
150
151			return mb_substr($x, -$num_bytes, null, '8bit');
152			}
153
154			/**
155			* @param int $s_bits
156			* @param int $x
157			*
158			* @return string
159			*/
160			private static function getInc($s_bits, $x)
161			{
162			$lsb = self::getLSB($s_bits, $x);
163			$X = self::toUInt32Bits($lsb) + 1;
164			$res = self::getMSB(self::getLength($x) - $s_bits, $x).pack('N', $X);
165
166			return $res;
167			}
168
169			/**
170			* @param string $bin
171			*
172			* @return mixed
173			*/
174			private static function toUInt32Bits($bin)
175			{
176			// $bin is the binary 32-bit BE string that represents the integer
177			$int_size = 4;
178			if ($int_size <= 4) {
179			list(, $h, $l) = unpack('n*', $bin);
180
181			return $l + ($h * 0x010000);
182			} else {
183			list(, $int) = unpack('N', $bin);
184
185			return $int;
186			}
187			}
188
189			/**
190			* @param $X
191			* @param $Y
192			*
193			* @return string
194			*/
195			private static function getProduct($X, $Y)
196			{
197			$R = pack('H*', 'E1').str_pad('', 15, "\0");
198			$Z = str_pad('', 16, "\0");
199			$V = $Y;
200
201			$parts = str_split($X, 4);
202			$x = sprintf('%032b%032b%032b%032b', self::toUInt32Bits($parts[0]), self::toUInt32Bits($parts[1]), self::toUInt32Bits($parts[2]), self::toUInt32Bits($parts[3]));
203			$lsb_mask = "\1";
204			for ($i = 0; $i < 128; $i++) {
205			if ($x[$i]) {
206			$Z = self::getBitXor($Z, $V);
207			}
208			$lsb_8 = mb_substr($V, -1, null, '8bit');
209			if (ord($lsb_8 & $lsb_mask)) {
210			$V = self::getBitXor(self::shiftStringToRight($V), $R);
211			} else {
212			$V = self::shiftStringToRight($V);
213			}
214			}
215
216			return $Z;
217			}
218
219			/**
220			* @param string $input
221			*
222			* @return string
223			*/
224			private static function shiftStringToRight($input)
225			{
226			$width = 4;
227			$parts = array_map('self::toUInt32Bits', str_split($input, $width));
228			$runs = count($parts);
229
230			for ($i = $runs - 1; $i >= 0; $i--) {
231			if ($i) {
232			$lsb1 = $parts[$i - 1] & 0x00000001;
233			if ($lsb1) {
234			$parts[$i] = ($parts[$i] >> 1) \| 0x80000000;
235			$parts[$i] = pack('N', $parts[$i]);
236			continue;
237			}
238			}
239			$parts[$i] = ($parts[$i] >> 1) & 0x7FFFFFFF; // get rid of sign bit
240			$parts[$i] = pack('N', $parts[$i]);
241			}
242			$res = implode('', $parts);
243
244			return $res;
245			}
246
247			/**
248			* @param string $H
249			* @param string $X
250			*
251			* @return mixed
252			*/
253			private static function getHash($H, $X)
254			{
255			$Y = [];
256			$Y[0] = str_pad('', 16, "\0");
257			$num_blocks = (int) (mb_strlen($X, '8bit') / 16);
258			for ($i = 1; $i <= $num_blocks; $i++) {
259			$Y[$i] = self::getProduct(self::getBitXor($Y[$i - 1], mb_substr($X, ($i - 1) * 16, 16, '8bit')), $H);
260			}
261
262			return $Y[$num_blocks];
263			}
264
265			/**
266			* @param string $K
267			* @param string $ICB
268			* @param string $X
269			*
270			* @return string
271			*/
272			private static function getGCTR($K, $ICB, $X)
273			{
274			if ($X == '') {
275			return '';
276			}
277
278			$n = (int) ceil(self::getLength($X) / 128);
279			$CB = [];
280			$Y = [];
281			$CB[1] = $ICB;
282			for ($i = 2; $i <= $n; $i++) {
283			$CB[$i] = self::getInc(32, $CB[$i - 1]);
284			}
285			$key_length = strlen($K) * 8;
286			$mode = 'aes-'.($key_length).'-ecb';
287			for ($i = 1; $i < $n; $i++) {
288			$C = openssl_encrypt($CB[$i], $mode, $K, OPENSSL_NO_PADDING \| OPENSSL_RAW_DATA);
289			$Y[$i] = self::getBitXor(mb_substr($X, ($i - 1) * 16, 16, '8bit'), $C);
290			}
291
292			$Xn = mb_substr($X, ($n - 1) * 16, null, '8bit');
293			$C = openssl_encrypt($CB[$n], $mode, $K, OPENSSL_NO_PADDING \| OPENSSL_RAW_DATA);
294			$Y[$n] = self::getBitXor($Xn, self::getMSB(self::getLength($Xn), $C));
295
296			return implode('', $Y);
297			}
298
299			/**
300			* @param string $o1
301			* @param string $o2
302			*
303			* @return string
304			*/
305			private static function getBitXor($o1, $o2)
306			{
307			$xorWidth = PHP_INT_SIZE;
308			$o1 = str_split($o1, $xorWidth);
309			$o2 = str_split($o2, $xorWidth);
310			$res = '';
311			$runs = count($o1);
312			for ($i = 0; $i < $runs; $i++) {
313			$res .= $o1[$i] ^ $o2[$i];
314			}
315
316			return $res;
317			}
318			}
319

Spomky-Labs / php-aes-gcm

Push — master ( a69544...c28e38 )

AESGCM::getHash() A

Complexity

Size

Duplication

Duplication Side-by-Side

Filter issues like