AesCtr::urs() - Code Metrics - Inspection of "2.1.27" - nilsteampassnet/TeamPass - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — development ( 1fb984...7ea9e3 )

by Nils

created 2017-12-19 17:48 UTC

AesCtr::urs() A

↳ Parent: AesCtr

Complexity

Conditions	3
Paths	2

Size

Total Lines	12
Code Lines	8

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	3
eloc	8
nc	2
nop	2
dl	0
loc	12
rs	9.4285
c	0
b	0
f	0

<?php
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
/*  AES counter (CTR) mode implementation in PHP (c) Chris Veness 2005-2010. Right of free use is */
/*    granted for all commercial or non-commercial use under CC-BY licence. No warranty of any    */
/*    form is offered.                                                                            */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */

class AesCtr extends Aes

{
    /**
     * Encrypt a text using AES encryption in Counter mode of operation
     *  - see http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf
     *
     * Unicode multi-byte character safe
     *
     * @param plaintext source text to be encrypted
     * @param password  the password to use to generate a key
     * @param nBits     number of bits to be used in the key (128, 192, or 256)
     * @return          string text
     */
    public static function encrypt($plaintext, $password, $nBits)
    {
    $blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES
    if (!($nBits == 128 || $nBits == 192 || $nBits == 256)) {
        return '';
    }
    // standard allows 128/192/256 bit keys
    // note PHP (5) gives us plaintext and password in UTF8 encoding!

    // use AES itself to encrypt password to get cipher key (using plain password as source for
    // key expansion) - gives us well encrypted key
    $nBytes = $nBits / 8; // no bytes in key
    $pwBytes = array();
    for ($i = 0; $i < $nBytes; $i++) {
        $pwBytes[$i] = ord(substr($password, $i, 1)) & 0xff;
    }
    $key = Aes::cipher($pwBytes, Aes::keyExpansion($pwBytes));
function acceptsInteger($int) { }

$x = '123'; // string "123"

// Instead of
acceptsInteger($x);

// we recommend to use
acceptsInteger((integer) $x);
    $key = array_merge($key, array_slice($key, 0, $nBytes - 16)); // expand key to 16/24/32 bytes long

    // initialise counter block (NIST SP800-38A §B.2): millisecond time-stamp for nonce in
    // 1st 8 bytes, block counter in 2nd 8 bytes
    $counterBlock = array();
    $nonce = floor(microtime(true) * 1000); // timestamp: milliseconds since 1-Jan-1970
    $nonceSec = floor($nonce / 1000);
    $nonceMs = $nonce % 1000;
    // encode nonce with seconds in 1st 4 bytes, and (repeated) ms part filling 2nd 4 bytes
    for ($i = 0; $i < 4; $i++) {
        $counterBlock[$i] = self::urs($nonceSec, $i * 8) & 0xff;
    }
    for ($i = 0; $i < 4; $i++) {
        $counterBlock[$i + 4] = $nonceMs & 0xff;
    }
    // and convert it to a string to go on the front of the ciphertext
    $ctrTxt = '';
    for ($i = 0; $i < 8; $i++) {
        $ctrTxt .= chr($counterBlock[$i]);
    }

    // generate key schedule - an expansion of the key into distinct Key Rounds for each round
    $keySchedule = Aes::keyExpansion($key);
function acceptsInteger($int) { }

$x = '123'; // string "123"

// Instead of
acceptsInteger($x);

// we recommend to use
acceptsInteger((integer) $x);
    //print_r($keySchedule);

    $blockCount = ceil(strlen($plaintext) / $blockSize);
    $ciphertxt = array(); // ciphertext as array of strings

    for ($b = 0; $b < $blockCount; $b++) {
        // set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes)
        // done in two stages for 32-bit ops: using two words allows us to go past 2^32 blocks (68GB)
        for ($c = 0; $c < 4; $c++) {
            $counterBlock[15 - $c] = self::urs($b, $c * 8) & 0xff;
        }
        for ($c = 0; $c < 4; $c++) {
            $counterBlock[15 - $c - 4] = self::urs($b / 0x100000000, $c * 8);
        }

        $cipherCntr = Aes::cipher($counterBlock, $keySchedule); // -- encrypt counter block --
function acceptsInteger($int) { }

$x = '123'; // string "123"

// Instead of
acceptsInteger($x);

// we recommend to use
acceptsInteger((integer) $x);

        // block size is reduced on final block
        $blockLength = $b < $blockCount - 1 ? $blockSize : (strlen($plaintext) - 1) % $blockSize + 1;
        $cipherByte = array();

        for ($i = 0; $i < $blockLength; $i++) {  // -- xor plaintext with ciphered counter byte-by-byte --
        $cipherByte[$i] = $cipherCntr[$i] ^ ord(substr($plaintext, $b * $blockSize + $i, 1));
        $cipherByte[$i] = chr($cipherByte[$i]);
        }
        $ciphertxt[$b] = implode('', $cipherByte); // escape troublesome characters in ciphertext
    }

    // implode is more efficient than repeated string concatenation
    $ciphertext = $ctrTxt.implode('', $ciphertxt);
    $ciphertext = base64_encode($ciphertext);

    return $ciphertext;
    }

    /**
     * Decrypt a text encrypted by AES in counter mode of operation
     *
     * @param ciphertext source text to be decrypted
     * @param password   the password to use to generate a key
     * @param nBits      number of bits to be used in the key (128, 192, or 256)
     * @return           string text
     */
    public static function decrypt($ciphertext, $password, $nBits)
    {
    $blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES
    if (!($nBits == 128 || $nBits == 192 || $nBits == 256)) {
        return '';
    }
    // standard allows 128/192/256 bit keys
    $ciphertext = base64_decode($ciphertext);

    // use AES to encrypt password (mirroring encrypt routine)
    $nBytes = $nBits / 8; // no bytes in key
    $pwBytes = array();
    for ($i = 0; $i < $nBytes; $i++) {
        $pwBytes[$i] = ord(substr($password, $i, 1)) & 0xff;
    }
    $key = Aes::cipher($pwBytes, Aes::keyExpansion($pwBytes));
function acceptsInteger($int) { }

$x = '123'; // string "123"

// Instead of
acceptsInteger($x);

// we recommend to use
acceptsInteger((integer) $x);
    $key = array_merge($key, array_slice($key, 0, $nBytes - 16)); // expand key to 16/24/32 bytes long

    // recover nonce from 1st element of ciphertext
    $counterBlock = array();
    $ctrTxt = substr($ciphertext, 0, 8);
    for ($i = 0; $i < 8; $i++) {
        $counterBlock[$i] = ord(substr($ctrTxt, $i, 1));
    }

    // generate key schedule
    $keySchedule = Aes::keyExpansion($key);
function acceptsInteger($int) { }

$x = '123'; // string "123"

// Instead of
acceptsInteger($x);

// we recommend to use
acceptsInteger((integer) $x);

    // separate ciphertext into blocks (skipping past initial 8 bytes)
    $nBlocks = ceil((strlen($ciphertext) - 8) / $blockSize);
    $ct = array();
    for ($b = 0; $b < $nBlocks; $b++) {
        $ct[$b] = substr($ciphertext, 8 + $b * $blockSize, 16);
    }
    $ciphertext = $ct; // ciphertext is now array of block-length strings

    // plaintext will get generated block-by-block into array of block-length strings
    $plaintxt = array();

    for ($b = 0; $b < $nBlocks; $b++) {
        // set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes)
        for ($c = 0; $c < 4; $c++) {
            $counterBlock[15 - $c] = self::urs($b, $c * 8) & 0xff;
        }
        for ($c = 0; $c < 4; $c++) {
            $counterBlock[15 - $c - 4] = self::urs(($b + 1) / 0x100000000 - 1, $c * 8) & 0xff;
        }

        $cipherCntr = Aes::cipher($counterBlock, $keySchedule); // encrypt counter block
function acceptsInteger($int) { }

$x = '123'; // string "123"

// Instead of
acceptsInteger($x);

// we recommend to use
acceptsInteger((integer) $x);

        $plaintxtByte = array();
        for ($i = 0; $i < strlen($ciphertext[$b]); $i++) {
        // -- xor plaintext with ciphered counter byte-by-byte --
        $plaintxtByte[$i] = $cipherCntr[$i] ^ ord(substr($ciphertext[$b], $i, 1));
        $plaintxtByte[$i] = chr($plaintxtByte[$i]);

        }
        $plaintxt[$b] = implode('', $plaintxtByte);
    }

    // join array of blocks into single plaintext string
    $plaintext = implode('', $plaintxt);

    return $plaintext;
    }

    /*
   * Unsigned right shift function, since PHP has neither >>> operator nor unsigned ints
   *
   * @param a  number to be shifted (32-bit integer)
   * @param b  number of bits to shift a to the right (0..31)
   * @return   a right-shifted and zero-filled by b bits
   */
    private static function urs($a, $b)
    {
    $a &= 0xffffffff; $b &= 0x1f; // (bounds check)
    if ($a & 0x80000000 && $b > 0) {   // if left-most bit set
        $a = ($a >> 1) & 0x7fffffff; //   right-shift one bit & clear left-most bit
        $a = $a >> ($b - 1); //   remaining right-shifts
    } else {                       // otherwise
        $a = ($a >> $b); //   use normal right-shift
    }

    return $a;
    }

}
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */


1		<?php
2		/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
3		/* AES counter (CTR) mode implementation in PHP (c) Chris Veness 2005-2010. Right of free use is */
4		/* granted for all commercial or non-commercial use under CC-BY licence. No warranty of any */
5		/* form is offered. */
6		/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
7
8	View Code Duplication	class AesCtr extends Aes
		0 ignored issues – show Duplication introduced 2017-06-02 20:17 UTC by Report Bug Copy Issue Report This class seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
9		{
10		/**
11		* Encrypt a text using AES encryption in Counter mode of operation
12		* - see http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf
13		*
14		* Unicode multi-byte character safe
15		*
16		* @param plaintext source text to be encrypted
17		* @param password the password to use to generate a key
18		* @param nBits number of bits to be used in the key (128, 192, or 256)
19		* @return string text
20		*/
21		public static function encrypt($plaintext, $password, $nBits)
22		{
23		$blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES
24		if (!($nBits == 128 \|\| $nBits == 192 \|\| $nBits == 256)) {
25		return '';
26		}
27		// standard allows 128/192/256 bit keys
28		// note PHP (5) gives us plaintext and password in UTF8 encoding!
29
30		// use AES itself to encrypt password to get cipher key (using plain password as source for
31		// key expansion) - gives us well encrypted key
32		$nBytes = $nBits / 8; // no bytes in key
33		$pwBytes = array();
34		for ($i = 0; $i < $nBytes; $i++) {
35		$pwBytes[$i] = ord(substr($password, $i, 1)) & 0xff;
36		}
37		$key = Aes::cipher($pwBytes, Aes::keyExpansion($pwBytes));
		0 ignored issues – show Documentation introduced 2017-06-02 20:17 UTC by Report Bug Copy Issue Report `$pwBytes` is of type `array`, but the function expects a `object<cipher>`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history... Documentation introduced 2017-06-02 20:17 UTC by Report Bug Copy Issue Report `$pwBytes` is of type `array`, but the function expects a `object<message>`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history... Documentation introduced 2017-06-02 20:17 UTC by Report Bug Copy Issue Report `\Aes::keyExpansion($pwBytes)` is of type `array`, but the function expects a `object<key>`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history...
38		$key = array_merge($key, array_slice($key, 0, $nBytes - 16)); // expand key to 16/24/32 bytes long
39
40		// initialise counter block (NIST SP800-38A §B.2): millisecond time-stamp for nonce in
41		// 1st 8 bytes, block counter in 2nd 8 bytes
42		$counterBlock = array();
43		$nonce = floor(microtime(true) * 1000); // timestamp: milliseconds since 1-Jan-1970
44		$nonceSec = floor($nonce / 1000);
45		$nonceMs = $nonce % 1000;
46		// encode nonce with seconds in 1st 4 bytes, and (repeated) ms part filling 2nd 4 bytes
47		for ($i = 0; $i < 4; $i++) {
48		$counterBlock[$i] = self::urs($nonceSec, $i * 8) & 0xff;
49		}
50		for ($i = 0; $i < 4; $i++) {
51		$counterBlock[$i + 4] = $nonceMs & 0xff;
52		}
53		// and convert it to a string to go on the front of the ciphertext
54		$ctrTxt = '';
55		for ($i = 0; $i < 8; $i++) {
56		$ctrTxt .= chr($counterBlock[$i]);
57		}
58
59		// generate key schedule - an expansion of the key into distinct Key Rounds for each round
60		$keySchedule = Aes::keyExpansion($key);
		0 ignored issues – show Documentation introduced 2017-06-02 20:17 UTC by Report Bug Copy Issue Report `$key` is of type `array<integer,?>`, but the function expects a `object<cipher>`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history...
61		//print_r($keySchedule);
62
63		$blockCount = ceil(strlen($plaintext) / $blockSize);
64		$ciphertxt = array(); // ciphertext as array of strings
65
66		for ($b = 0; $b < $blockCount; $b++) {
67		// set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes)
68		// done in two stages for 32-bit ops: using two words allows us to go past 2^32 blocks (68GB)
69		for ($c = 0; $c < 4; $c++) {
70		$counterBlock[15 - $c] = self::urs($b, $c * 8) & 0xff;
71		}
72		for ($c = 0; $c < 4; $c++) {
73		$counterBlock[15 - $c - 4] = self::urs($b / 0x100000000, $c * 8);
74		}
75
76		$cipherCntr = Aes::cipher($counterBlock, $keySchedule); // -- encrypt counter block --
		0 ignored issues – show Documentation introduced 2017-06-02 20:17 UTC by Report Bug Copy Issue Report `$counterBlock` is of type `array`, but the function expects a `object<message>`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history... Documentation introduced 2017-06-02 20:17 UTC by Report Bug Copy Issue Report `$keySchedule` is of type `array`, but the function expects a `object<key>`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history...
77
78		// block size is reduced on final block
79		$blockLength = $b < $blockCount - 1 ? $blockSize : (strlen($plaintext) - 1) % $blockSize + 1;
80		$cipherByte = array();
81
82		for ($i = 0; $i < $blockLength; $i++) { // -- xor plaintext with ciphered counter byte-by-byte --
83		$cipherByte[$i] = $cipherCntr[$i] ^ ord(substr($plaintext, $b * $blockSize + $i, 1));
84		$cipherByte[$i] = chr($cipherByte[$i]);
85		}
86		$ciphertxt[$b] = implode('', $cipherByte); // escape troublesome characters in ciphertext
87		}
88
89		// implode is more efficient than repeated string concatenation
90		$ciphertext = $ctrTxt.implode('', $ciphertxt);
91		$ciphertext = base64_encode($ciphertext);
92
93		return $ciphertext;
94		}
95
96		/**
97		* Decrypt a text encrypted by AES in counter mode of operation
98		*
99		* @param ciphertext source text to be decrypted
100		* @param password the password to use to generate a key
101		* @param nBits number of bits to be used in the key (128, 192, or 256)
102		* @return string text
103		*/
104		public static function decrypt($ciphertext, $password, $nBits)
105		{
106		$blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES
107		if (!($nBits == 128 \|\| $nBits == 192 \|\| $nBits == 256)) {
108		return '';
109		}
110		// standard allows 128/192/256 bit keys
111		$ciphertext = base64_decode($ciphertext);
112
113		// use AES to encrypt password (mirroring encrypt routine)
114		$nBytes = $nBits / 8; // no bytes in key
115		$pwBytes = array();
116		for ($i = 0; $i < $nBytes; $i++) {
117		$pwBytes[$i] = ord(substr($password, $i, 1)) & 0xff;
118		}
119		$key = Aes::cipher($pwBytes, Aes::keyExpansion($pwBytes));
		0 ignored issues – show Documentation introduced 2017-06-02 20:17 UTC by Report Bug Copy Issue Report `$pwBytes` is of type `array`, but the function expects a `object<cipher>`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history... Documentation introduced 2017-06-02 20:17 UTC by Report Bug Copy Issue Report `$pwBytes` is of type `array`, but the function expects a `object<message>`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history... Documentation introduced 2017-06-02 20:17 UTC by Report Bug Copy Issue Report `\Aes::keyExpansion($pwBytes)` is of type `array`, but the function expects a `object<key>`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history...
120		$key = array_merge($key, array_slice($key, 0, $nBytes - 16)); // expand key to 16/24/32 bytes long
121
122		// recover nonce from 1st element of ciphertext
123		$counterBlock = array();
124		$ctrTxt = substr($ciphertext, 0, 8);
125		for ($i = 0; $i < 8; $i++) {
126		$counterBlock[$i] = ord(substr($ctrTxt, $i, 1));
127		}
128
129		// generate key schedule
130		$keySchedule = Aes::keyExpansion($key);
		0 ignored issues – show Documentation introduced 2017-06-02 20:17 UTC by Report Bug Copy Issue Report `$key` is of type `array<integer,?>`, but the function expects a `object<cipher>`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history...
131
132		// separate ciphertext into blocks (skipping past initial 8 bytes)
133		$nBlocks = ceil((strlen($ciphertext) - 8) / $blockSize);
134		$ct = array();
135		for ($b = 0; $b < $nBlocks; $b++) {
136		$ct[$b] = substr($ciphertext, 8 + $b * $blockSize, 16);
137		}
138		$ciphertext = $ct; // ciphertext is now array of block-length strings
139
140		// plaintext will get generated block-by-block into array of block-length strings
141		$plaintxt = array();
142
143		for ($b = 0; $b < $nBlocks; $b++) {
144		// set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes)
145		for ($c = 0; $c < 4; $c++) {
146		$counterBlock[15 - $c] = self::urs($b, $c * 8) & 0xff;
147		}
148		for ($c = 0; $c < 4; $c++) {
149		$counterBlock[15 - $c - 4] = self::urs(($b + 1) / 0x100000000 - 1, $c * 8) & 0xff;
150		}
151
152		$cipherCntr = Aes::cipher($counterBlock, $keySchedule); // encrypt counter block
		0 ignored issues – show Documentation introduced 2017-06-02 20:17 UTC by Report Bug Copy Issue Report `$counterBlock` is of type `array`, but the function expects a `object<message>`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history... Documentation introduced 2017-06-02 20:17 UTC by Report Bug Copy Issue Report `$keySchedule` is of type `array`, but the function expects a `object<key>`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history...
153
154		$plaintxtByte = array();
155		for ($i = 0; $i < strlen($ciphertext[$b]); $i++) {
156		// -- xor plaintext with ciphered counter byte-by-byte --
157		$plaintxtByte[$i] = $cipherCntr[$i] ^ ord(substr($ciphertext[$b], $i, 1));
158		$plaintxtByte[$i] = chr($plaintxtByte[$i]);
159
160		}
161		$plaintxt[$b] = implode('', $plaintxtByte);
162		}
163
164		// join array of blocks into single plaintext string
165		$plaintext = implode('', $plaintxt);
166
167		return $plaintext;
168		}
169
170		/*
171		* Unsigned right shift function, since PHP has neither >>> operator nor unsigned ints
172		*
173		* @param a number to be shifted (32-bit integer)
174		* @param b number of bits to shift a to the right (0..31)
175		* @return a right-shifted and zero-filled by b bits
176		*/
177		private static function urs($a, $b)
178		{
179		$a &= 0xffffffff; $b &= 0x1f; // (bounds check)
180		if ($a & 0x80000000 && $b > 0) { // if left-most bit set
181		$a = ($a >> 1) & 0x7fffffff; // right-shift one bit & clear left-most bit
182		$a = $a >> ($b - 1); // remaining right-shifts
183		} else { // otherwise
184		$a = ($a >> $b); // use normal right-shift
185		}
186
187		return $a;
188		}
189
190		}
191		/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
192

nilsteampassnet / TeamPass

Push — development ( 1fb984...7ea9e3 )

AesCtr::urs() A

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