如何让 Ruby AES-256-CBC 和 PHP MCRYPT_RIJNDAEL_128 一起玩

2022-01-07 00:00:00 openssl ruby aes php mcrypt

我正在生成要从 Ruby 堆栈发送到 PHP 堆栈的数据.我在 Ruby 端使用 OpenSSL::Cipher 库，在 PHP 中使用mcrypt"库.当我在 Ruby 中使用aes-256-cbc"(256 位块大小)加密时，我需要在 PHP 中使用 MCRYPT_RIJNDAEL_128(128 位块大小)来解密它.我怀疑是损坏的 Ruby 代码，因为 cipher.iv_len 是 16；我认为应该是 32:

I'm generating data to send from a Ruby stack to a PHP stack. I'm using the OpenSSL::Cipher library on the Ruby side and the 'mcrypt' library in PHP. When I encrypt using 'aes-256-cbc' (256-bit block size) in Ruby I need to use MCRYPT_RIJNDAEL_128 (128-bit block size) in PHP to decrypt it. I suspect the Ruby code that is broken, because the cipher.iv_len is 16; I believe it should be 32:

>> cipher = OpenSSL::Cipher::Cipher.new('aes-128-cbc')
=> #<OpenSSL::Cipher::Cipher:0x3067c5c>
>> cipher.key_len
=> 16
>> cipher.iv_len
=> 16
>> cipher = OpenSSL::Cipher::Cipher.new('aes-256-cbc')
=> #<OpenSSL::Cipher::Cipher:0x306de18>
>> cipher.key_len
=> 32
>> cipher.iv_len
=> 16

这是我的测试.在 Ruby 端，我首先生成密钥和 iv:

So here's my test. On the Ruby side, first I generate the key and iv:

>> cipher = OpenSSL::Cipher::Cipher.new('aes-256-cbc')
>> cipher.encrypt
>> iv = cipher.random_iv
>> iv64 = [iv].pack("m").strip
=> "vCkaypm5tPmtP3TF7aWrug=="
>> key = cipher.random_key
>> key64 = [key].pack("m").strip
=> "RIvFgoi9xZaHS/0Bp0J9WDRyND6Z7jrd3btiAfcQ8Y0="

然后我使用这些密钥进行加密:

Then I use those keys to do the encryption:

>> plain_data = "Hi, Don, this is a string."
>> cipher = OpenSSL::Cipher::Cipher.new('aes-256-cbc')
>> cipher.encrypt
>> cipher.key = Base64.decode64(key64)
>> cipher.iv = Base64.decode64(iv64)
>> encrypted_data = cipher.update(plain_data)
>> encrypted_data << cipher.final
>> crypt64 = [encrypted_data].pack("m").strip
=> "5gfC/kJcnAV2fJI0haxnLcdraIKWgtu54UoznVxf8K0="

这是PHP解密:

$ruby_crypt = "5gfC/kJcnAV2fJI0haxnLcdraIKWgtu54UoznVxf8K0=";
$encrypted_data = base64_decode($ruby_crypt);
$key = base64_decode("RIvFgoi9xZaHS/0Bp0J9WDRyND6Z7jrd3btiAfcQ8Y0=");
$iv = base64_decode("vCkaypm5tPmtP3TF7aWrug==");
$result = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $encrypted_data, MCRYPT_MODE_CBC, $iv);
$unencrypt = rtrim($result, "x00..x1F");
print "
Unencrypted token:
'$unencrypt'
";

RESULT:
Unencrypted token:
'Hi, Don, this is a string.'

我更喜欢使用更长的块大小.显然我误解了 API.有帮助吗?

I'd prefer to use the longer block size. Clearly I'm misunderstanding the APIs. Help?

推荐答案

我不懂 PHP，但看了侧边栏的相关问题，我看到了 将 Ruby AES256 解密函数转换为 PHP.这包括对本页的引用，指出MCRYPT_RIJNDAEL_128中的128 指的是加密的块大小，而不是密钥大小.您会注意到，在这两种情况下，您在 ruby​​ 和 PHP 之间传递的密钥大小都是 256 位.换句话说，这似乎是预期的行为，而您已经在使用更大的密钥.

I don't know PHP, but reading through related questions on the sidebar, I see Converting Ruby AES256 decrypt function to PHP. This includes a reference to this page, pointing out that the 128 in MCRYPT_RIJNDAEL_128 refers to the block size of the encryption, not the key size. You'll notice that the key size that you've passed between ruby and PHP is 256 bits in both cases. In other words, this seems to be the expected behavior, and you are using the larger key already.

#!/usr/bin/ruby
require 'base64'

puts((Base64.decode64("RIvFgoi9xZaHS/0Bp0J9WDRyND6Z7jrd3btiAfcQ8Y0=").length * 8).to_s)

HTH

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