将药剂加密和解密逻辑映射到PHP，反之亦然

Question

我试图用Elixir和PHP编写逻辑来加密和解密文本。我的目标是解密用药剂加密的数据，反之亦然。这两种算法都工作得很好，但我遇到的唯一问题是将初始化向量与密码文本分离，并在PHP中将二进制文件转换为字符串，以及在Elixir中将解密文本转换为字符串。

Elixir实现：

    defmodule Crypto.AES do
    @block_size 16
    @secret_key "something secret here"

    def encrypt(text) do
        secret_key_hash = make_hash(@secret_key, 32)

        IO.inspect secret_key_hash

        # create random Initialisation Vector
        iv = :crypto.strong_rand_bytes(@block_size)

        text = pad_pkcs7(text, @block_size)
        encrypted_text = :crypto.crypto_one_time(:aes_256_cbc, secret_key_hash, iv, text, true )
        
        encrypted_text = ( iv <> <<"::">> <>  encrypted_text )
        
        Base.encode64(encrypted_text)
    end

    def decrypt(ciphertext) do
        secret_key_hash = make_hash(@secret_key, 32)

        {:ok, ciphertext} = Base.decode64(ciphertext)
        <<iv::binary-16, rp::binary-2, ciphertext::binary>> = ciphertext
        decrypted_text = :crypto.crypto_one_time(:aes_256_cbc, secret_key_hash, iv, ciphertext, false)

        unpad_pkcs7(decrypted_text)
    end
    
    @doc """
    Pad the `message` by extending it to the nearest `blocksize` boundary,
    appending the number of bytes of padding to the end of the block.
    If the original `message` is a multiple of `blocksize`, an additional block
    of bytes with value `blocksize` is added.
    """

    def pad_pkcs7(message, blocksize) do
        pad = blocksize - rem(byte_size(message), blocksize)
        message <> to_string(List.duplicate(pad, pad))
    end

    @doc """
    Remove the PKCS#7 padding from the end of `data`.
    """
    def unpad_pkcs7(data) do
        <<pad>> = binary_part(data, byte_size(data), -1)
        binary_part(data, 0, byte_size(data) - pad)
    end

    def make_hash(text, length) do
      :crypto.hash(:sha512, text)
        |> Base.encode16
        |> String.downcase
        |> String.slice(0, length)
    end

end

PHP实现：

    <?php
    $ENCRYPTION_KEY = 'something secret here';
    $ENCRYPTION_ALGORITHM = 'AES-256-CBC';

    function encrypt($plain_text) {
        global $ENCRYPTION_KEY;
        global $ENCRYPTION_ALGORITHM;
        $EncryptionKey = make_hash($ENCRYPTION_KEY, 32);

        // create random Initialisation Vector
        $iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length($ENCRYPTION_ALGORITHM));

        $encrypted_text = openssl_encrypt(
            $plain_text,
            $ENCRYPTION_ALGORITHM,
            $EncryptionKey,
            0,
            $iv
        );

        return  base64_encode($encrypted_text . '::' . $iv);
    }

    function decrypt($ciphertext) {
        global $ENCRYPTION_KEY;
        global $ENCRYPTION_ALGORITHM;
        $EncryptionKey = make_hash($ENCRYPTION_KEY, 32);

        $split = explode('::', base64_decode($ciphertext), 2);
        list($iv, $encrypted_text) = array_pad($split, 2, null);

        $plain_text = openssl_decrypt(
            $encrypted_text,
            $ENCRYPTION_ALGORITHM,
            $EncryptionKey,
            0,
            $iv
        );

        return $plain_text;
    }

    function make_hash($text, $length) {
        $hash_key = hash("sha512", $text, false);
        return substr($hash_key,0,$length);
    }

    $ct = encrypt("hello");
    // echo $ct."\n";
    echo decrypt("Sr4nMnMdDHhUQcnW6RwZ2Do6rhBh/ytW1W/x7Xx2/Xrv3A==")."\n";
?>

请提出一些可能的解决办法。谢谢

Answer 1

这两项守则是不相容的，原因有二：

• PHP代码返回加密过程中默认编码的密文Base64。这必须禁用，因为Base64编码是在IV和密文连接后显式执行的。通过将OPENSSL_RAW_DATA作为openssl_encrypt()中的第四个参数传递，可以禁用。这同样适用于解密： $encrypted_text = openssl_encrypt( $plain_text，$ENCRYPTION_ALGORITHM，$EncryptionKey，OPENSSL_RAW_DATA，// Fix:不要Base64编码密文$iv )；$plain_text = openssl_decrypt( $encrted_text，$ENCRYPTION_ALGORITHM，$EncryptionKey，OPENSSL_RAW_DATA，// Fix:不要Base64解码密文$iv )；
• 正如注释中已经指出的，这两种代码在解密期间分离时都假定了IV和密文的不同顺序。Menwhile您已经调整了PHP代码中解密期间的分离，使之与Elixir代码的分离相适应。 但是对于加密，这两种代码都使用了不同的IV和密文顺序。有关加密的PHP代码的修改仍未完成： ..。返回base64_encode($iv .“：”。( $encrypted_text)；//反向顺序

通过这些更改，这两个代码在功能上是相同的，用PHP代码生成的密文可以用Elixir代码解密，反之亦然。

关于级联的注意事项: IV和密文都可以以一定的概率包含分隔符::，这可能会导致问题。最好是在没有分隔符的情况下将数据连接起来，并使用已知的IV长度进行分离。

此外，使用散列函数进行密钥派生是不安全的，最好应用可靠的密钥派生函数，如PBKDF2。此外，采用十六进制编码密钥而不是二进制数据降低了安全性。

Answer 2

使用@Topaco的建议( PBKDF2除外，稍后将添加)，这是完整的解决方案。

Elixir - git-链接

defmodule Crypto.AES do
    @block_size 16
    @secret_key "put something secret here"

    def encrypt(plain_text) do
        secret_key_hash = make_hash(@secret_key, 32)

        # create Initialisation Vector
        iv = :crypto.strong_rand_bytes(@block_size)

        padded_text = pad_pkcs7(plain_text, @block_size)
        encrypted_text = :crypto.crypto_one_time(:aes_256_cbc, secret_key_hash, iv, padded_text, true )
        
        # concatenate IV for decryption
        encrypted_text = ( iv <>  encrypted_text )
        
        Base.encode64(encrypted_text)
    end

    def decrypt(ciphertext) do
        secret_key_hash = make_hash(@secret_key, 32)

        {:ok, ciphertext} = Base.decode64(ciphertext)
        <<iv::binary-16, ciphertext::binary>> = ciphertext
        decrypted_text = :crypto.crypto_one_time(:aes_256_cbc, secret_key_hash, iv, ciphertext, false)

        unpad_pkcs7(decrypted_text)
    end
    
    defp pad_pkcs7(message, blocksize) do
        pad = blocksize - rem(byte_size(message), blocksize)
        message <> to_string(List.duplicate(pad, pad))
    end

    defp unpad_pkcs7(data) do
        <<pad>> = binary_part(data, byte_size(data), -1)
        binary_part(data, 0, byte_size(data) - pad)
    end

    defp make_hash(text, length) do
      :crypto.hash(:sha512, text)
        |> Base.encode16
        |> String.downcase
        |> String.slice(0, length)
    end

end

- 要点-链接

<?php
    $ENCRYPTION_KEY = "put something secret here";
    $ENCRYPTION_ALGORITHM = 'AES-256-CBC';

    function encrypt($plain_text) {
        global $ENCRYPTION_KEY;
        global $ENCRYPTION_ALGORITHM;
        $EncryptionKey = make_hash($ENCRYPTION_KEY, 32);

        // create random Initialization Vector
        $iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length($ENCRYPTION_ALGORITHM));

        $encrypted_text = openssl_encrypt(
            $plain_text,
            $ENCRYPTION_ALGORITHM,
            $EncryptionKey,
            OPENSSL_RAW_DATA,
            $iv 
        );

        # concatenate the IV for decryption
        return  base64_encode($iv . $encrypted_text);
    }

    function decrypt($ciphertext) {
        global $ENCRYPTION_KEY;
        global $ENCRYPTION_ALGORITHM;
        $EncryptionKey = make_hash($ENCRYPTION_KEY, 32);

        $ciphertext = base64_decode($ciphertext);
        // get Initialization Vector part (16 bytes long)
        $iv = substr($ciphertext, 0, 16);
        // rest is actual cipher text
        $ciphertext = substr($ciphertext, 16);

        $decrypted_text = openssl_decrypt(
            $ciphertext,
            $ENCRYPTION_ALGORITHM,
            $EncryptionKey,
            OPENSSL_RAW_DATA,
            $iv
        );

        return $decrypted_text;
    }

    function make_hash($text, $length) {
        $hash_key = hash("sha512", $text, false);
        return substr($hash_key,0,$length);
    }

    // $ct = encrypt("code");
    // $dt = decrypt($ct);
    // echo $ct."\n";
    // echo $dt."\n";
?>