PHP 7.0.6 Released

    Mcrypt

    User Contributed Notes

    Anonymous
    4 years ago
    These are two simple functions I built for 256-bit encryption/decryption with mcrypt.  I've decided to use MCRYPT_RIJNDAEL_128 because it's AES-compliant, and MCRYPT_MODE_CBC.  (ECB mode is inadequate for many purposes because it does not use an IV.)

    This function stores a hash of the data to verify that the data was decrypted successfully, but this could be easily removed if necessary.

    <?php
    function encrypt($decrypted, $password, $salt='!kQm*fF3pXe1Kbm%9') {
    // Build a 256-bit $key which is a SHA256 hash of $salt and $password.
    $key = hash('SHA256', $salt . $password, true);
    // Build $iv and $iv_base64.  We use a block size of 128 bits (AES compliant) and CBC mode.  (Note: ECB mode is inadequate as IV is not used.)
    srand(); $iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC), MCRYPT_RAND);
    if (    strlen($iv_base64 = rtrim(base64_encode($iv), '=')) != 22) return false;
    // Encrypt $decrypted and an MD5 of $decrypted using $key.  MD5 is fine to use here because it's just to verify successful decryption.
    $encrypted = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, $decrypted . md5($decrypted), MCRYPT_MODE_CBC, $iv));
    // We're done!
    return $iv_base64 . $encrypted;
    }

    function     decrypt($encrypted, $password, $salt='!kQm*fF3pXe1Kbm%9') {
    // Build a 256-bit $key which is a SHA256 hash of $salt and $password.
    $key = hash('SHA256', $salt . $password, true);
    // Retrieve $iv which is the first 22 characters plus ==, base64_decoded.
    $iv = base64_decode(substr($encrypted, 0, 22) . '==');
    // Remove $iv from $encrypted.
    $encrypted = substr($encrypted, 22);
    // Decrypt the data.  rtrim won't corrupt the data because the last 32 characters are the md5 hash; thus any \0 character has to be padding.
    $decrypted = rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, base64_decode($encrypted), MCRYPT_MODE_CBC, $iv), "\0\4");
    // Retrieve $hash which is the last 32 characters of $decrypted.
    $hash = substr($decrypted, -32);
    // Remove the last 32 characters from $decrypted.
    $decrypted = substr($decrypted, 0, -32);
    // Integrity check.  If this fails, either the data is corrupted, or the password/salt was incorrect.
    if (md5($decrypted) != $hash) return false;
    // Yay!
    return $decrypted;
    }
    ?>
    ghoffman at salientdigital dot com
    5 years ago
    If you want a quick way to see what ciphers, modes, key, block and iv sizes are supported on your server, try something like the following.

    Note: I used this simple bash: `locate libmcrypt` from terminal on Mac OS X to determine the install paths to the algorithms and modes directories. Lots of function calls generate warnings for certain ciphers, hence the use of error suppression.

    <?php

    $modes     = mcrypt_list_modes();
    $algorithms = mcrypt_list_algorithms();
    foreach(    $algorithms as $cipher)
    {
        echo     "<h1 style=\"border-top:1px solid black;\">".$cipher."</h1>\n";
        foreach(    $modes as $mode)
        {
            echo     "<h3>".$mode."</h3>\n";
            @    $td = mcrypt_module_open(
                    $cipher,
                    '/usr/local/libmcrypt-2.5.8/modules/algorithms/',
                    $mode,
                    '/usr/local/libmcrypt-2.5.8/modules/modes/');
            @    $key_size = mcrypt_enc_get_key_size($td);
            @    $block_size = mcrypt_get_block_size($cipher,$mode);
            @    $iv_size = mcrypt_get_iv_size($cipher, $mode);
            @    mcrypt_module_close($td);
            echo     "
            <pre> 
                key_size: "    . ($key_size?$key_size:'n/a')
          .    "    block_size: ". ($block_size?$block_size:'n/a')
          .    "    iv_size: ". ($iv_size?$iv_size:'n/a')
          .    "  </pre>\n";
                $td=NULL;
                $key_size=NULL;
                $block_size=NULL;
                $iv_size=NULL;
        }
    }

    ?>
    Maarten Malaise
    6 years ago
    people using phpmyadmin are redirected to this manual if they don't have mcrypt installed. If you want to install mcrypt on debian, first check your php version:

    yourserver# php --version

    Then install the appropriate version of mcrypt (php5-mcrypt if your php version is 5.x)

    yourserver# apt-get install php4-mcrypt
    ...or...
    yourserver# apt-get install php5-mcrypt
    simonhf at gmail dot com
    10 months ago
    Note that there are severe performance problems with PHP mcrypt on many CentOS versions. Please see this CentOS bug:
    http://bugs.centos.org/view.php?id=8954
    ysfbauchi at yahoo dot com
    5 years ago
    //This is a des, 3des, aes and gost encryption program i wrote using php for my assignment

    <?php
            if (isset($_REQUEST['select'])) {
            $choice = $_POST['select'];
              $mykey = $_POST['mykey'];
            $msg = $_POST['plain'];
        } else {
        die(    "algorithm not selected");
          }

        if (    $msg == ''){
            die(    "Please enter a text to encrypt! ");
            }
        if (    $mykey == ''){
            die(    "Please enter a key! ");
            }        
       
        function     algorithmdetails($cipher)
        {
                $chiphername = mcrypt_enc_get_algorithms_name($cipher);
                $blocksize = mcrypt_enc_get_block_size($cipher);
                $mykeysize = mcrypt_enc_get_supported_key_sizes($cipher);
            echo     "<p><b>Cipher Name :</b> $chiphername";   
            echo     "<p><b>Block size :</b> $blocksize bytes";
            echo     "<p><b>Key size :</b> ";   
            foreach (    $mykeysize as $value)
            {
            echo     "$value bytes ";
            }unset(    $value);
        }
       
        function     encryptnow($thecipher, $thekey, $themsg)
        {
                $iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($thecipher), MCRYPT_DEV_RANDOM);
                mcrypt_generic_init($thecipher, $thekey, $iv);
                $encrypted_text = mcrypt_generic($thecipher, $themsg);
            echo     "<html><hr size='2' ></html>";
            echo     "<P><P><b>Plain Text : </b>";
            echo(    $themsg);
            echo     "<p><b>Cipher Text : </b> ";
            echo     "$encrypted_text";
                mcrypt_generic_deinit($thecipher);
                mcrypt_module_close($thecipher);
            die();
        }
       
        if (    $choice == '1'){
                $cipher = mcrypt_module_open (MCRYPT_DES, '', 'ecb', '');
                algorithmdetails($cipher);
                encryptnow($cipher, $mykey, $msg);
       
        }elseif (    $choice == '2'){
                $cipher = mcrypt_module_open (MCRYPT_3DES, '', 'ecb', '');
                algorithmdetails($cipher);
                encryptnow($cipher, $mykey, $msg);
       
        }elseif (    $choice == '3'){
                $cipher = mcrypt_module_open (MCRYPT_RIJNDAEL_128, '', 'ecb', '');
                algorithmdetails($cipher);
                encryptnow($cipher, $mykey, $msg);
       
        }elseif (    $choice == '4'){
                $cipher = mcrypt_module_open (MCRYPT_GOST, '', 'ecb', '');
                algorithmdetails($cipher);
                encryptnow($cipher, $mykey, $msg);
           
        }else {
            die(    "Please choose an algorithm!");
        }   
       
    ?>
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