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<?php
namespace app\common\wework\callback;
/**
* PKCS7Encoder class
*
* 提供基于PKCS7算法的加解密接口.
*/
class PKCS7Encoder
{
public static $block_size = 32;
/**
* 对需要加密的明文进行填充补位
* @param $text 需要进行填充补位操作的明文
* @return 补齐明文字符串
*/
function encode($text)
{
$block_size = PKCS7Encoder::$block_size;
$text_length = strlen($text);
//计算需要填充的位数
$amount_to_pad = PKCS7Encoder::$block_size - ($text_length % PKCS7Encoder::$block_size);
if ($amount_to_pad == 0) {
$amount_to_pad = PKCS7Encoder::block_size;
}
//获得补位所用的字符
$pad_chr = chr($amount_to_pad);
$tmp = "";
for ($index = 0; $index < $amount_to_pad; $index++) {
$tmp .= $pad_chr;
}
return $text . $tmp;
}
/**
* 对解密后的明文进行补位删除
* @param decrypted 解密后的明文
* @return 删除填充补位后的明文
*/
function decode($text)
{
$pad = ord(substr($text, -1));
if ($pad < 1 || $pad > PKCS7Encoder::$block_size) {
$pad = 0;
}
return substr($text, 0, (strlen($text) - $pad));
}
}