使用System.Security.Cryptography加密文本以匹配OpenSSL

2 回答

• 2

  感谢GregS's Point in the right direction，很容易复制EVP_BytesToKey()中发生的Key和Initial Vector生成 .

  基本上他们创建了一个48字节的数组（用于密钥的32字节数组和用于IV的16字节数组），并使用SHA1将私钥和8个盐字节散列到该缓冲区中 . 第一个哈希只是私钥和盐，连续哈希是生成的最后一个哈希，它与密钥和盐字节连接起来，直到48字节数组被填满 .

  密钥只是前32个字节，IV是最后16个字节 .

  使用System.Security.Crytpography中的AESManaged类以及从此方法派生的密钥和IV，我能够以使用OpenSSL库的第三方可以解密的方式加密我的密码 .

  这是我用来导出密钥和初始向量的算法：

  /// <summary>
      /// Derives the key and IV.
      /// </summary>
      /// <param name="saltBytes">The salt bytes.</param>
      /// <param name="privateKeyBytes">The private key bytes.</param>
      /// <param name="iv">The iv.</param>
      /// <returns>The Key</returns>
      private static byte[] DeriveKeyAndIV(byte[] saltBytes, byte[] privateKeyBytes, out byte[] iv)
      {
          // we are creating a 16 byte initial vector and a 32 byte key 
          const int ivLength   = 16;
          iv = new byte[ivLength];
          const int keyLength  = 32;
          var key = new byte[keyLength];
  
          //SHA1 creates a 20 byte hash
          const int hashLength = 20;
  
          // container to store the hashed values
          var keyContainer = new byte[keyLength + ivLength];
  
          // munge together the privateKey and salt
          var privateKeyAndSalt = new byte[privateKeyBytes.Length + saltBytes.Length];
          Array.Copy(privateKeyBytes, privateKeyAndSalt, privateKeyBytes.Length);
          Array.Copy(saltBytes, 0, privateKeyAndSalt, privateKeyBytes.Length, saltBytes.Length);
  
          // use SHA1 crypto to match the -md SHA1 command line.
          var sha1 = new SHA1CryptoServiceProvider();
  
          // hashtarget holds the successive hash's source bytes.
          var hashtarget = new byte[hashLength + privateKeyAndSalt.Length];
  
          byte[] currentHash = null;
          var bytesCopied = 0;
  
          // do the hashing until we fill the container
          while (bytesCopied < (ivLength + keyLength))
          {
              // Hash(0) is an empty set so just concatenate private key and salt.
              if (currentHash == null)
              {
                  currentHash = sha1.ComputeHash(privateKeyAndSalt);
              }
              else
              {
                  // successive hashes are done on Hash(prev) + private key + salt.
                  Array.Copy(currentHash, hashtarget, currentHash.Length);
                  Array.Copy(privateKeyAndSalt, 0, hashtarget, currentHash.Length, privateKeyAndSalt.Length);
                  currentHash = hashtarget;
                  currentHash = sha1.ComputeHash(currentHash);
              }
              var copyAmount = Math.Min(currentHash.Length, keyContainer.Length - bytesCopied);
              Array.Copy(currentHash, 0, keyContainer, bytesCopied, copyAmount);
              bytesCopied += copyAmount;
          }
  
          // split out bytes in the container. first 32 are key, last 16 are iv.
          Array.Copy(keyContainer, 0, key, 0, key.Length);
          Array.Copy(keyContainer, key.Length, iv, 0, iv.Length);
  
          return key;
      }
  

  回复于 2024-04-29T18:01:32+08:00
• 1

  我在相关的openssl源（ apps/enc.c ）中略微探讨了一下，我认为openssl使用了一种有点专有的方法 . 我承认我懒得弄清楚所有的细节，但他们在那里 . 看起来ASCII字符串"Salted__"后跟8个随机盐字节被添加到文件中 . AES密钥和AES iv使用名为EVP_BytesToKey()的openssl方法从密码和salt派生 . 该手册中描述了该算法 . 在版本1.0.0a的 enc.c source code中，此部分从第510行开始 .

  希望这可以帮助你入门 .

  回复于 2024-04-29T18:01:32+08:00