Question

我正在尝试对SSN等敏感数据进行加密/解密，加密过程顺利，DB中的保存看起来也很好，检索看起来也很好，但是当我在解密数据的最后一步时，我收到错误message：要解密的数据长度无效。

我创建了一个用于测试的SQL Server表，其中有一列用于保存数据，大小为500的varbinary类型。

这是表中数据的样子：

enter image description here

现在这里是C＃中的完整代码，用于加密数据，插入数据库，获取最后一条记录（测试）和解密。正如我所说，错误发生在解密步骤的最后一步：

加密步骤

 public byte[] EncryptStringToBytes(string plainText)
 {
             // Check arguments. 
             if (plainText == null || plainText.Length <= 0)
                 throw new ArgumentNullException("plainText");           
             byte[] encrypted;
             // Create an RijndaelManaged object 
             // with the specified key and IV. 
             using (RijndaelManaged rijAlg = new RijndaelManaged())
             {
                 rijAlg.Mode = CipherMode.CBC;
                 rijAlg.Padding = PaddingMode.PKCS7;
                 string keyStr = "cGFzc3dvcmQAAAAAAAAAAA==";
                 string ivStr = "cGFzc3dvcmQAAAAAAAAAAA==";
                 byte[] ivArr = Convert.FromBase64String(keyStr);
                 byte[] keyArr = Convert.FromBase64String(ivStr);
                 rijAlg.Key = keyArr;
                 rijAlg.KeySize = 256;
                 rijAlg.BlockSize = 128;
                 rijAlg.IV = ivArr;

                 // Create a decrytor to perform the stream transform.
                 ICryptoTransform encryptor = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.IV);

                 // Create the streams used for encryption. 
                 using (MemoryStream msEncrypt = new MemoryStream())
                 {
                     using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                     {
                         using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                         {
                             //Write all data to the stream.
                             swEncrypt.Write(plainText);
                         }
                         encrypted = msEncrypt.ToArray();
                         SaveData(encrypted);
                     }
                 }
            }
             // Return the encrypted bytes from the memory stream. 
             return encrypted;
         }

将数据保存到数据库

public void SaveData(byte[] cipherText) {
   string queryStmt = "INSERT INTO TestSSN(SSN) VALUES(@Content)";

   using (SqlConnection _con = new SqlConnection(ConfigurationManager.ConnectionStrings["ApplicationServices"].ConnectionString))
   using (SqlCommand _cmd = new SqlCommand(queryStmt, _con))
   {
      SqlParameter param = _cmd.Parameters.Add("@Content", SqlDbType.VarBinary);
      param.Value = cipherText;

      _con.Open();
      _cmd.ExecuteNonQuery();
      _con.Close();
   }
   GetSSNData(1); }

从数据库中获取数据

public byte[] GetSSNData(int id)
{
    byte[] cipherData = new byte[500];
    string queryStmt = "SELECT SSN FROM TestSSN WHERE ID=7";

    using (SqlConnection _con = new SqlConnection(ConfigurationManager.ConnectionStrings["ApplicationServices"].ConnectionString))
    using (SqlCommand _cmd = new SqlCommand(queryStmt, _con))
    {              
          _con.Open();
          SqlDataReader rdr = _cmd.ExecuteReader();

          if (rdr.HasRows)
          {
              while (rdr.Read())
              {
                    cipherData = Encoding.ASCII.GetBytes(rdr[0].ToString());
              }
          }
          _con.Close();
    }
    string roundtrip = DecryptStringFromBytes(cipherData);          
    return cipherData;
}

尝试解密数据（你会在这里注意到两种不同的解密方式，但我会同时收到相同的消息）

 static string DecryptStringFromBytes(byte[] cipherText)
 {
     // Check arguments. 
     if (cipherText == null || cipherText.Length <= 0)
         throw new ArgumentNullException("cipherText");           

     // Declare the string used to hold 
     // the decrypted text. 
     string plaintext = null;

     // Create an RijndaelManaged object 
     // with the specified key and IV. 
     using (RijndaelManaged rijAlg = new RijndaelManaged())
     {
         rijAlg.Mode = CipherMode.CBC;
         rijAlg.Padding = PaddingMode.PKCS7;
         string keyStr = "cGFzc3dvcmQAAAAAAAAAAA==";
         string ivStr = "cGFzc3dvcmQAAAAAAAAAAA==";
         byte[] ivArr = Convert.FromBase64String(keyStr);
         byte[] keyArr = Convert.FromBase64String(ivStr);
         rijAlg.Key = keyArr;
         rijAlg.KeySize = 256;
         rijAlg.BlockSize = 128;
         rijAlg.IV = ivArr;
         // Create a decrytor to perform the stream transform.
         ICryptoTransform decryptor = rijAlg.CreateDecryptor(rijAlg.Key, rijAlg.IV);

         byte[] decryptedText = decryptor.TransformFinalBlock(cipherText, 0, cipherText.Length);
         string decrpyted = ASCIIEncoding.UTF8.GetString(decryptedText);          

         // Create the streams used for decryption. 
         using (MemoryStream msDecrypt = new MemoryStream(cipherText))
         {
             using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
             {
                 using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                 {
                     //  byte[] decryptedText = decryptor.TransformFinalBlock(cipherText, 0, cipherText.Length);
                     // Read the decrypted bytes from the decrypting stream 
                     // and place them in a string.
                     plaintext = srDecrypt.ReadToEnd();
                 }
             }
         }
     }

     return plaintext;
   }

建议更多，然后欢迎，我一整天都在与解密作斗争。

谢谢，Laziale

Answer 1

检查从DB读取数据的位置：

cipherData = Encoding.ASCII.GetBytes(rdr[0].ToString());

如果rdr[0]是byte数组，我认为你不会得到字节串，可能你会得到“System.Byte []”。如果你得到“0xFFAA” - Encoding.ASCII.GetBytes将不会给你一个带有{0xFF，0xAA}数据的字节数组。您应该使用SqlDataReader.GetBytes来读取此数据。

另外，我想提醒您SSN是敏感信息。您应该通知您的用户您将保存此信息。如果您需要此信息来验证身份 - 您可以使用最后4位数字或哈希值。如果您没有真正的理由，请考虑不保存SSN。

要解密的数据长度是无效的rijndael c＃sql

1 个答案: