Question

我收到此错误：

Warning: mcrypt_decrypt(): The IV parameter must be as long as the blocksize

它来自加密变量，其代码与php手册网站（http://php.net/manual/en/function.mcrypt-encrypt.php）上的代码大致相同。它完全在一起工作（我把它分成两个用作include()文件，并添加了方便的输入和输出变量）。它加密一个值，在$ _GET变量上发布它，然后在下一页加载它解密它。但是，在解密时，我收到错误。我猜它可能与将加密信息保存在$ _GET变量上然后读取它有关。在一个实例中，URL中的加密文本和$ _GET标识符如下所示：Last_Song_ID=mIyFkMdMgVgSZU18wD/vJ3bI8qf++ea1/NtGrsajKd4=

在此文件中（错误发生在靠近底部的$ciphertext_dec, MCRYPT_MODE_CBC, $iv_dec);处：

include('key.php');

$ciphertext_base64 = $de_in;

$ciphertext_dec = base64_decode($ciphertext_base64);

$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
echo $iv_size . "<br>";

# retrieves the IV, iv_size should be created using mcrypt_get_iv_size()
$iv_dec = substr($ciphertext_dec, 0, $iv_size);

# retrieves the cipher text (everything except the $iv_size in the front)
$ciphertext_dec = substr($ciphertext_dec, $iv_size);

# may remove 00h valued characters from end of plain text
$plaintext_utf8_dec = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key,
                                     $ciphertext_dec, MCRYPT_MODE_CBC, $iv_dec);

$de_out = $plaintext_utf8_dec;

加密文本来自主文件中的$ _GET变量，该变量来自以下内容：

<?php
    # --- ENCRYPTION ---

    # the key should be random binary, use scrypt, bcrypt or PBKDF2 to
    # convert a string into a key
    # key is specified using hexadecimal
    include('key.php');

    # show key size use either 16, 24 or 32 byte keys for AES-128, 192
    # and 256 respectively
    $key_size =  strlen($key);
    //echo "Key size: " . $key_size . "\n";

    if(!isset($en_in))
    $en_in = "No Input";

    # create a random IV to use with CBC encoding
    $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
    echo $iv_size . "<br>";
    $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);

    # use an explicit encoding for the plain text
    $plaintext_utf8 = utf8_encode($en_in);

    # creates a cipher text compatible with AES (Rijndael block size = 128)
    # to keep the text confidential 
    # only suitable for encoded input that never ends with value 00h
    # (because of default zero padding)
    $ciphertext = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key,
                                 $plaintext_utf8, MCRYPT_MODE_CBC, $iv);

    # prepend the IV for it to be available for decryption
    $ciphertext = $iv . $ciphertext;

    # encode the resulting cipher text so it can be represented by a string
    $ciphertext_base64 = base64_encode($ciphertext);

    $en_out = $ciphertext_base64;


?>

Answer 1

您无法传递base 64 via GET parameter，因为这些是有效的base64字符，可能会与GET参数发生冲突：

ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789 + / =

所以你可能没有像预期的那样检索整个GET，而只是一部分。您可能希望这样做以检查：

最后一行编码：

echo strlen($en_out);

在编码开始时：

echo strlen($de_in);

如果尺寸彼此不匹配，那就是你的问题，由于上面提到和链接的原因，整件事情没有正确传递。

编辑：关于解决方案，链接问题的第一个和第二个答案都非常好。

收到错误警告：mcrypt_decrypt（）：IV参数必须与块大小一样长

1 个答案: