我正在尝试加密/解密敏感数据，例如 SSN，加密过程很顺利，保存在数据库中看起来也不错，检索看起来也不错，但是当我在解密数据的最后一步时，我收到错误消息：长度要解密的数据无效。
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，varbinary类型为 500。
这是表格中数据的样子：
现在这是 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（你会注意到这里有两种不同的解密方式，但我会得到同样的信息）
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;
}
欢迎提出更多建议，我整天都在与解密作斗争。
谢谢，拉齐尔