Completed
Branch master (bd23f7)
by Joao
03:53 queued 01:39
created

TripleDes::decrypt()   A

Complexity

Conditions 1
Paths 1

Size

Total Lines 14
Code Lines 8

Duplication

Lines 0
Ratio 0 %

Importance

Changes 1
Bugs 0 Features 1
Metric Value
c 1
b 0
f 1
dl 0
loc 14
rs 9.4285
cc 1
eloc 8
nc 1
nop 1
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<?php
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namespace ByJG\Crypto;
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abstract class TripleDes implements CryptoInterface
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{
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    abstract public function getKeys();
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    public function getKeyPart($keyNumber, $part)
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    {
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        $keyPart = $this->getKeys();
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        $blockSize = mcrypt_get_block_size(MCRYPT_3DES, MCRYPT_MODE_CBC) * 2;
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        if ($part == 1) {
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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.

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            return substr(hex2bin($keyPart[$keyNumber]), 0, $blockSize);
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        } else {
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            return substr(hex2bin($keyPart[$keyNumber]), -$blockSize);
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        }
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    }
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    public function encrypt($plainText)
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    {
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        $maxPossibleKeys = count($this->getKeys()) - 1;
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        $blockSize = mcrypt_get_block_size(MCRYPT_3DES, MCRYPT_MODE_CBC);
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        $bitA = rand(0, $maxPossibleKeys);
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        $bitB = rand(0, $maxPossibleKeys);
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        $key = $this->getKeyPart($bitA, 1);
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        $iv = substr($this->getKeyPart($bitB, 2), 0, $blockSize);
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        $padded = $this->pkcs5Pad($plainText, $blockSize);
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        $encText = mcrypt_encrypt(MCRYPT_3DES, $key, $padded, MCRYPT_MODE_CBC, $iv);
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        return base64_encode(bin2hex(chr($bitA)) . bin2hex(chr($bitB)) . $encText);
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    }
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    public function decrypt($encryptText) {
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        $cipherText = base64_decode($encryptText);
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        $bitA = ord(hex2bin(substr($cipherText, 0, 2)));
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        $bitB = ord(hex2bin(substr($cipherText, 2, 2)));
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        $key = $this->getKeyPart($bitA, 1);
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        $iv = substr($this->getKeyPart($bitB, 2), 0, mcrypt_get_block_size(MCRYPT_3DES, MCRYPT_MODE_CBC));
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        $res = mcrypt_decrypt(MCRYPT_3DES, $key, substr($cipherText, 4), MCRYPT_MODE_CBC, $iv);
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        return $this->pkcs5Unpad($res);
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    }
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    protected function pkcs5Pad ($text, $blocksize)
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    {
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        $pad = $blocksize - (strlen($text) % $blocksize);
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        return $text . str_repeat(chr($pad), $pad);
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    }
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    protected function pkcs5Unpad($text)
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    {
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        $pad = ord($text{strlen($text)-1});
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        if ($pad > strlen($text)) {
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            return false;
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        }
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        if (strspn($text, chr($pad), strlen($text) - $pad) != $pad) {
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            return false;
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        }
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        return substr($text, 0, -1 * $pad);
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    }
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}
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