OCRA_v1::_hexStr2Bytes() - Code Metrics - Inspection of "Build tool maintenance: enable php-scrutinizer-run..." - Tiqr/tiqr-server-libphp - Measure and Improve Code Quality continuously with Scrutinizer

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by Pieter van der
created 2022-02-04 14:47 UTC
OCRA_v1::_hexStr2Bytes() A

↳ Parent: OCRA_v1
Complexity

Conditions	1
Paths	1
Size

Total Lines	2
Code Lines	1
Duplication

Lines	0
Ratio	0 %
Importance

Changes	1
Bugs	1	Features	0
Metric	Value
eloc	1
c	1
b	1
f	0
dl	0
loc	2
rs	10
cc	1
nc	1
nop	1
<?php 
/**
 * This file is part of the tiqr project.
 * 
 * The tiqr project aims to provide an open implementation for 
 * authentication using mobile devices. It was initiated by 
 * SURFnet and developed by Egeniq.
 *
 * More information: http://www.tiqr.org
 *
 * @author Ivo Jansch <[email protected]>
 * 
 * @package tiqr
 *
 * @license New BSD License - See LICENSE file for details.
 *
 * @copyright (C) 2010-2011 SURFnet BV
 */


/**
 * This a PHP port of the example implementation of the 
 * OATH OCRA algorithm.
 * Visit www.openauthentication.org for more information.
 *
 * @author Johan Rydell, PortWise (original Java)
 * @author Ivo Jansch, Egeniq (PHP port)
 */
class OCRA_v1 {

    private function __construct() {
        
    }

    /**
     * This method uses the hmac_hash function to provide the crypto
     * algorithm.
     * HMAC computes a Hashed Message Authentication Code with the
     * crypto hash algorithm as a parameter.
     *
     * @param String crypto     the crypto algorithm (sha1, sha256 or sha512)
     * @param String keyBytes   the bytes to use for the HMAC key
     * @param String text       the message or text to be authenticated.
filter:
    dependency_paths: ["lib/*"]
     */
    private static function _hmac_sha1($crypto,
            $keyBytes,
            $text)
    {
         $hash = hash_hmac ($crypto, $text, $keyBytes);
         return $hash;
    }

    /**
     * This method converts HEX string to Byte[]
     *
     * @param String hex   the HEX string
filter:
    dependency_paths: ["lib/*"]
     *
     * @return String a string with raw bytes
     */
    private static function _hexStr2Bytes($hex){
        return pack("H*", $hex);
    }


    /**
     * This method generates an OCRA HOTP value for the given
     * set of parameters.
     *
     * @param ocraSuite    the OCRA Suite
     * @param key          the shared secret, HEX encoded
     * @param counter      the counter that changes
     *                     on a per use basis,
     *                     HEX encoded
     * @param question     the challenge question, HEX encoded
filter:
    dependency_paths: ["lib/*"]
     * @param password     a password that can be used,
     *                     HEX encoded
     * @param sessionInformation
     *                     Static information that identifies the
     *                     current session, Hex encoded
     * @param timeStamp    a value that reflects a time
     *
     * @return A numeric String in base 10 that includes
     * {@link truncationDigits} digits
     */
    static function generateOCRA($ocraSuite,

                                 $key,
                                 $counter,
                                 $question,
                                 $password,
                                 $sessionInformation,
                                 $timeStamp)
    {
        $codeDigits = 0;

        $crypto = "";
        $result = null;

        $ocraSuiteLength = strlen($ocraSuite);
        $counterLength = 0;
        $questionLength = 0;
        $passwordLength = 0;

        $sessionInformationLength = 0;
        $timeStampLength = 0;

        if(stripos($ocraSuite, "sha1")!==false)
            $crypto = "sha1";
        if(stripos($ocraSuite, "sha256")!==false)
            $crypto = "sha256";
        if(stripos($ocraSuite, "sha512")!==false)
            $crypto = "sha512";

        // How many digits should we return
        $oS = substr($ocraSuite, strpos($ocraSuite, ":")+1, strpos($ocraSuite, ":", strpos($ocraSuite, ":")+1) -strpos($ocraSuite, ":")-1);
        $codeDigits = substr($oS, strrpos($oS, "-")+1);
        
        // The size of the byte array message to be encrypted
        // Counter
        if(stripos($ocraSuite, ":c") !==false) {
            // Fix the length of the HEX string
            while(strlen($counter) < 16)
                $counter = "0" . $counter;
            $counterLength=8;
        }
        // Question
        if(stripos($ocraSuite, ":q")!==false ||
                stripos($ocraSuite, "-q")!==false) {
            while(strlen($question) < 256)
                $question = $question . "0";
            $questionLength=128;
        }

        // Password
        if(stripos($ocraSuite, ":p")!==false ||
                stripos($ocraSuite, "-p") !==false) {
            while(strlen($password) < 40)
                $password = "0" . $password;
            $passwordLength=20;
        }

        // sessionInformation
        if(stripos($ocraSuite, ":s") !==false ||
                stripos($ocraSuite, "-s", strpos($ocraSuite, ":", strpos($ocraSuite, ":")+1)) !== false) {
            while(strlen($sessionInformation) < 128)
                $sessionInformation = "0" . $sessionInformation;

            $sessionInformationLength=64;
        }
             
        // TimeStamp
        if(stripos($ocraSuite, ":t") !==false ||
                stripos($ocraSuite, "-t") !== false) {
            while(strlen($timeStamp) < 16)
                $timeStamp = "0" . $timeStamp;
            $timeStampLength=8;
        }

        // Put the bytes of "ocraSuite" parameters into the message
        
        $msg = array_fill(0,$ocraSuiteLength+$counterLength+$questionLength+$passwordLength+$sessionInformationLength+$timeStampLength+1, 0);
                
        for($i=0;$i<strlen($ocraSuite);$i++) {
            $msg[$i] = $ocraSuite[$i];
        }
        
        // Delimiter
        $msg[strlen($ocraSuite)] = self::_hexStr2Bytes("0");

        // Put the bytes of "Counter" to the message
        // Input is HEX encoded
        if($counterLength > 0 ) {
            $bArray = self::_hexStr2Bytes($counter);
            for ($i=0;$i<strlen($bArray);$i++) {
                $msg [$i + $ocraSuiteLength + 1] = $bArray[$i];
            }
        }


        // Put the bytes of "question" to the message
        // Input is text encoded
        if($questionLength > 0 ) {
            $bArray = self::_hexStr2Bytes($question);
            for ($i=0;$i<strlen($bArray);$i++) {
                $msg [$i + $ocraSuiteLength + 1 + $counterLength] = $bArray[$i];
            }
        }

        // Put the bytes of "password" to the message
        // Input is HEX encoded
        if($passwordLength > 0){
            $bArray = self::_hexStr2Bytes($password);
            for ($i=0;$i<strlen($bArray);$i++) {
                $msg [$i + $ocraSuiteLength + 1 + $counterLength + $questionLength] = $bArray[$i];
            }
        }

        // Put the bytes of "sessionInformation" to the message
        // Input is text encoded
        if($sessionInformationLength > 0 ){
            $bArray = self::_hexStr2Bytes($sessionInformation);
            for ($i=0;$i<strlen($bArray);$i++) {
                $msg [$i + $ocraSuiteLength + 1 + $counterLength + $questionLength + $passwordLength] = $bArray[$i];
            }
        }

        // Put the bytes of "time" to the message
        // Input is text value of minutes
        if($timeStampLength > 0){
            $bArray = self::_hexStr2Bytes($timestamp);

            for ($i=0;$i<strlen($bArray);$i++) {
                $msg [$i + $ocraSuiteLength + 1 + $counterLength + $questionLength + $passwordLength + $sessionInformationLength] = $bArray[$i];
            }
        }
        
        $byteKey = self::_hexStr2Bytes($key);
              
        $msg = implode("", $msg);
        
        $hash = self::_hmac_sha1($crypto, $byteKey, $msg);
        
        $result = self::_oath_truncate($hash, $codeDigits);
        $result = self::_oath_truncate($hash, $codeDigits);
             
        return $result;

    }

    /**
     * Truncate a result to a certain length
     */    
    function _oath_truncate($hash, $length = 6)

    {
        // Convert to dec
        foreach(str_split($hash,2) as $hex)
        {
            $hmac_result[]=hexdec($hex);
        }
    
        // Find offset
        $offset = $hmac_result[19] & 0xf;

    
        // Algorithm from RFC
        return
        (
            (($hmac_result[$offset+0] & 0x7f) << 24 ) |
            (($hmac_result[$offset+1] & 0xff) << 16 ) |
            (($hmac_result[$offset+2] & 0xff) << 8 ) |
            ($hmac_result[$offset+3] & 0xff)
        ) % pow(10,$length);
    }
    
}

Tiqr / tiqr-server-libphp

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OCRA_v1::_hexStr2Bytes() A

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