mcrypt加密了一串'％00'到字符串的结尾 [英] mcrypt encrypt adding s bunch of '%00' to end of string

问题描述

使用OAuth并使用我们称为foo的字符串（实际上是OAuth令牌）使用以下功能加密密钥。

  public function encrypt（$ text）
 {
 //添加文本分隔符的结尾
 $ data = mcrypt_encrypt（MCRYPT_RIJNDAEL_128，$ this-> key，$ text，MCRYPT_MODE_ECB ，$ this-> iv）; 
返回base64_encode（$ data）; 
} 
  

当我使用反函数解密时，我最终得到： p>

功能：

  public function decrypt（ $ text）
 {
 $ text = base64_decode（$ text）; 
 return mcrypt_decrypt（MCRYPT_RIJNDAEL_128，$ this-> key，$ text，MCRYPT_MODE_ECB，$ this-> iv）; 
} 
  

结果：

foo％00％00％00％00％00％00％00％00％00％00％00％00％00％00

编辑：

再看一下，我意识到实际上是URL编码到％00，这意味着我的字符串以某种方式被空字符填充？所以我目前正在使用trim（）来摆脱它们，但是我想了解为什么会发生这种情况。

解决方案

Rijndael是块密码，这意味着它对特定长度的数据块进行操作（在这种情况下为128位） 。这意味着如果输入文本的长度不是块大小的倍数，则必须将其填充以适合。在这种情况下，填充为零;还有一些其他可能的填充方案可以使用，但如果您希望使用PHP的mcrypt你必须手动应用它们。

Working with OAuth and encrypting the keys with the following function with a string which we'll call 'foo' (actually an OAuth token)

public function encrypt( $text )
{
    // add end of text delimiter
    $data = mcrypt_encrypt( MCRYPT_RIJNDAEL_128, $this->key, $text, MCRYPT_MODE_ECB, $this->iv );
    return base64_encode( $data );
}

When I decrypt it using the inverse function, I end up with:

Function:

    public function decrypt( $text )
    {
        $text = base64_decode( $text );
        return mcrypt_decrypt( MCRYPT_RIJNDAEL_128, $this->key, $text, MCRYPT_MODE_ECB, $this->iv );
    }

Result:

foo%00%00%00%00%00%00%00%00%00%00%00%00%00%00

Edit:

Looking at it a little more, I realized that it is actually URL encoding to %00, which means that my strings are somehow being padded by null characters? So I am currently using trim() to get rid of them, but I would like to understand why this is happening.

解决方案

Rijndael is a block cypher, which means that it operates on chunks of data of a particular length (128 bits in this case). This means that if the length of the input text is not a multiple of the block size, it must be padded out to fit. In this case, the padding is zeros; there are a number of other possible padding schemes that could be used, but if you want them with PHP's mcrypt you'll have to apply them manually.

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