PHP’s mcrypt ciphers, block modes, block sizes and IVs compared

Below is a comparison of PHP’s mcrypt ciphers, block modes, block sizes and IVs. Note that some ciphers support multiple key sizes. Also note that some ciphers are made for encrypting streams of data, unchained and therefore are not supported by the other modes — and vice versa.

If you wish to run this code yourself…

<?php

$ciphers = mcrypt_list_algorithms();

$blockModes = array('cbc',
                    'ecb',
                    'ofb',
                    'nofb',
                    'cfb',
                    'ncfb',
                    'ctr',
                    'stream');
                    
?>
<table>
    <thead>
        <tr>
            <th>Cipher Name</th>
            <th>Block Mode</th>
            <th>Block Size</th>
            <th>IV Size</th>
            <th>Default Key Size</th>
            <th>All Key Size(s)</th>
        </tr>
    </thead>
    <tbody>
<?php

foreach($ciphers as $cipher) {

    foreach($blockModes as $blockMode) {
    
        if(@mcrypt_get_block_size($cipher, $blockMode) !== false) {
        
?>
        <tr>
            <td><?= mcrypt_get_cipher_name($cipher) ?></td>
            <td><?= strtoupper($blockMode) ?></td>
            <td><?= mcrypt_get_block_size($cipher, $blockMode) ?></td>
            <td><?= mcrypt_get_iv_size($cipher, $blockMode) ?></td>
            <td><?= mcrypt_get_key_size($cipher, $blockMode) ?></td>
            <td><?php
            
            foreach(mcrypt_module_get_supported_key_sizes($cipher) as $keySize) {
            
                echo $keySize . ' ';
            
            }
            
            ?></td>
        </tr>
<?php

        }
        else {
        
?>
        <tr>
            <td colspan="6"><?= mcrypt_get_cipher_name($cipher) . ' not supported in ' . strtoupper($blockMode) . ' mode' ?></td>
        </tr>
<?php
        
        }
    
    }

}

?>
    </tbody>
</table>