php做DES加密，仿PKCS5填充方式做自定义字符填充

<?php
function encrypt_something($input)
{
$size = mcrypt_get_block_size('des', 'ecb');
$input = pkcs5_pad($input, $size);

$key = 'YOUR SECRET KEY HERE';
$td = mcrypt_module_open('des', '', 'ecb', '');
$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
mcrypt_generic_init($td, $key, $iv);
$data = mcrypt_generic($td, $input);
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
$data = base64_encode($data);
return $data;
}

//填充部分，如果block为8字节，注意当加密字节数刚好是8的整数倍，也要在结尾填充8个字节
function pkcs5_pad ($text, $blocksize)
{
$pad = $blocksize - (strlen($text) % $blocksize);
return $text . str_repeat(chr($pad), $pad);
}

function pkcs5_unpad($text)
{
$pad = ord($text{strlen($text)-1});
if ($pad > strlen($text)) return false;
if (strspn($text, chr($pad), strlen($text) - $pad) != $pad) return false;
return substr($text, 0, -1 * $pad);
}
?>

<?php
function makePattern( $key, $text )
{
$blocksize = mcrypt_get_block_size( 'des', 'ecb' );
$padn = $blocksize - ( strlen( $text ) % $blocksize );
$pad = substr( strrev( $text ), 0, 1 );      //注意此处为我自定义的填充字符
$text = $text.str_repeat( $pad, $padn );

$td = mcrypt_module_open( 'des', '', 'ecb', '' );
$iv = mcrypt_create_iv ( mcrypt_enc_get_iv_size( $td ), MCRYPT_RAND );
mcrypt_generic_init( $td, $key, $iv );
$data = mcrypt_generic( $td, $text );
mcrypt_generic_deinit( $td );
mcrypt_module_close( $td );
return base64_encode( $data );
}
?>