我已将我的PHP版本更新为7.1.
我有使用Mcrypt加密数据的功能.
现在不推荐使用此功能.

无论如何我都可以通过回到旧版本的PHP来解密数据.

这是我使用的代码：

public function encrypt($plaintext) {
    $ivSize = mcrypt_get_iv_size(self::CIPHER,self::MODE);
    $iv = mcrypt_create_iv($ivSize,MCRYPT_DEV_URANDOM);
    $ciphertext = mcrypt_encrypt(self::CIPHER,$this->key,$plaintext,self::MODE,$iv);
    return base64_encode($iv.$ciphertext);
}

public function decrypt($ciphertext) {
    $ciphertext = base64_decode($ciphertext);
    $ivSize = mcrypt_get_iv_size(self::CIPHER,self::MODE);
    if (strlen($ciphertext) < $ivSize) {
        throw new Exception('Missing inITialization vector');
    }

    $iv = substr($ciphertext,$ivSize);
    $ciphertext = substr($ciphertext,$ivSize);
    $plaintext = mcrypt_decrypt(self::CIPHER,$ciphertext,$iv);
    return rtrim($plaintext,"\0");
}

使用常量：

const CIPHER = MCRYPT_RIJNDAEL_128; // Rijndael-128 is AES
const MODE   = MCRYPT_MODE_CBC;

我看到建议使用OPEnSSL.这是我将从现在开始使用的.但是如何使用此方法解密旧数据？

谢谢

编辑：
我知道我可以使用OpenSSL作为替代方案.
这就是我从现在开始为内容做的事情.
但是我需要从旧内容中解密我的加密代码.

*编辑请求@symcbean

尝试用OpenSSL解密如下：

public function decrypt($ciphertext) {
    $ciphertext = base64_decode($ciphertext);

    if (!function_exists("openssl_decrypt")) {
       throw new Exception("aesDecrypt needs openssl PHP module.");
    }

$key    = $this->key;
$method = 'AES-256-CBC';
$ivSize = openssl_cipher_iv_length($method);
$iv     = substr($ciphertext,$ivSize);
$data   = substr($ciphertext,$ivSize);
$clear  = openssl_decrypt ($data,$method,$key,'OPENSSL_RAW_DATA'|'OPENSSL_ZERO_PADDING',$iv);

return $clear;
}

$data = "Lorem ipsum";
$key = "1234567890abcdef";
$iv = "1234567890abcdef";

$encrypted = mcrypt_encrypt(
    MCRYPT_RIJNDAEL_128,$data,MCRYPT_MODE_CBC,$iv);
echo bin2hex($encrypted) . "\n";

$decrypted = openssl_decrypt(
    $encrypted,"AES-128-CBC",OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING,$iv);
echo var_export($decrypted,true) . "\n";
$result = rtrim($decrypted,"\0");
echo VAR_export($result,true) . "\n";

70168f2d5751b3d3bf36b7e6b8ec5843
'Lorem ipsum' . "\0" . '' . "\0" . '' . "\0" . '' . "\0" . '' . "\0" . ''
'Lorem ipsum'