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我需要将尽可能多的字符存储在具有 char 字符串的 cookie 上，以便以 AES 加密存储。

cookie 有大约 4kb 的内存。

所以我需要计算在 AES 中加密所有这些字符的 cookie 中可以存储多少字符。

要存储的字符是一个字母数字字符串。

编辑：我可以在明文和 Chipertext 中允许所有 UTF-8 字母数字字符

这是我的一段代码

 <?php


$Pass = "132ksjcngpt04938idjsk39urtokg";
$Clear = "123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123456789012345678901234567890123456789o";


$crypted = fnEncrypt($Clear, $Pass);
echo "Encrypred: ".$crypted."<br></br>";

$newClear = fnDecrypt($crypted, $Pass);
echo "Decrypred: ".$newClear."<br></br>";



function fnEncrypt($sValue, $sSecretKey)
{
    return trim(
        base64_encode(
            mcrypt_encrypt(
                MCRYPT_RIJNDAEL_128,
                $sSecretKey, $sValue, 
                MCRYPT_MODE_ECB, 
                mcrypt_create_iv(
                    mcrypt_get_iv_size(
                        MCRYPT_RIJNDAEL_128, 
                        MCRYPT_MODE_ECB
                    ), 
                    MCRYPT_RAND)
                )
            )
        );
}

function fnDecrypt($sValue, $sSecretKey)
{
    return trim(
        mcrypt_decrypt(
            MCRYPT_RIJNDAEL_128, 
            $sSecretKey, 
            base64_decode($sValue), 
            MCRYPT_MODE_ECB,
            mcrypt_create_iv(
                mcrypt_get_iv_size(
                    MCRYPT_RIJNDAEL_128,
                    MCRYPT_MODE_ECB
                ), 
                MCRYPT_RAND
            )
        )
    );
}
?>

我测试了，结果如下：

Encrypred: 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

Decrypred: 123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123hryd{}ls.-''ksllasllallallallallal:{}::{}jdhhfn123456789012345678901234567890123456789o

chiperText 由 3040 个 utf-8 字符组成

加密最多 4056 个 utf-8 字符

4

2 回答 2

1

如果我错了，请纠正我，但假设您使用 UTF-8 作为纯文本的字母数字字符，因为 AES 使用 16 个字节长度的块（在这种情况下可以视为 16 个字母数字字符），您的纯文本至少是填充 15 个字节（最坏的情况）。

因此，给定n纯文本的长度，可以通过以下方式推断得到的密文长度：

(n + 16) - (n % 16)

只是我的2美分。达里奥。

于 2012-10-07T15:50:30.220 回答
1

如果您使用经过身份验证的流模式，例如 AES-GCM，则原始密文大小（以字节为单位）将比明文大小大 32 个字节。其中 16 个用于随机 IV，16 个用于 MAC。

现在你遇到了任意字节不是有效的 UTF-8 的问题，所以你需要一些编码来处理这个问题。Base64 是一种流行的变体，但它会将大小增加到原始大小的 4/3。
这意味着如果您的大小限制为 4KiB，您将能够支持最多 3040 字节的纯文本。

还有其他更有效的编码，但会变得更复杂，您需要确定哪些字符是有效的（例如\0）。除非绝对必要，否则我不建议这样做。

您的代码有很多错误：

  1. 您正在使用欧洲央行，几乎是所有模式中最糟糕的
  2. 您需要相同的 IV 进行加密和解密。因此，将其与密文一起存储。你不会注意到它，因为欧洲央行不使用 IV。
  3. 您没有身份验证。
  4. 你的IV代不好。使用MCRYPT_DEV_URANDOM而不是MCRYPT_RAND.
于 2012-10-07T16:17:09.877 回答