从CodeBehind C＃解密SQLDataSource

Question

I have the following SQLDataSource:

<asp:SqlDataSource ID="myDataSource" runat="server" ConnectionString="<%$ ConnectionStrings:myConnString %>" SelectCommand="SELECT [ID], [Name] FROM [myTable] WHERE (([IsActive] = @IsActive))">
                        <SelectParameters>
                            <asp:Parameter DefaultValue="True" Name="IsActive" Type="Boolean" />
                        </SelectParameters>
</asp:SqlDataSource>

I am Encrypting and Decrypting my connectionstring using the following method:

        const string initVector = "4s}T*3Rka&5Z2qE_";
        const string saltValue = "Ly8$}7Qm9Fi*x2=D";
        const string passPhrase = "K!i3nL9_P=y5o6}Z";
        const int keySize = 256;
        const int passwordIterations = 13;
        public static string Decrypt(string cipherText)
        {
            string strReturn = string.Empty;
            try
            {
                byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector);
                byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue);
                byte[] cipherTextBytes = Convert.FromBase64String(cipherText);
                Rfc2898DeriveBytes password = new Rfc2898DeriveBytes(passPhrase, saltValueBytes, passwordIterations);
                byte[] keyBytes = password.GetBytes(keySize / 8);
                RijndaelManaged symmetricKey = default(RijndaelManaged);
                symmetricKey = new RijndaelManaged();
                symmetricKey.Mode = CipherMode.CBC;
                ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes);
                MemoryStream memoryStream = new MemoryStream(cipherTextBytes);
                CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
                byte[] plainTextBytes = null;
                plainTextBytes = new byte[cipherTextBytes.Length + 1];
                int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
                memoryStream.Close();
                cryptoStream.Close();
                strReturn = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
            }
            catch (Exception ex)
            {
                strReturn = null;
            }
            return strReturn;
        }

        public static string Encrypt(string plainText)
        {
            string strReturn = string.Empty;

            try
            {
                byte[] initVectorBytes = null;
                initVectorBytes = System.Text.Encoding.ASCII.GetBytes(initVector);

                byte[] saltValueBytes = null;
                saltValueBytes = System.Text.Encoding.ASCII.GetBytes(saltValue);

                byte[] plainTextBytes = null;
                plainTextBytes = System.Text.Encoding.UTF8.GetBytes(plainText);

                Rfc2898DeriveBytes password = default(Rfc2898DeriveBytes);

                password = new Rfc2898DeriveBytes(passPhrase, saltValueBytes, passwordIterations);
                byte[] keyBytes = null;
                int intKeySize = 0;

                intKeySize = Convert.ToInt32((keySize / 8));

                keyBytes = password.GetBytes(intKeySize);

                System.Security.Cryptography.RijndaelManaged symmetricKey = default(System.Security.Cryptography.RijndaelManaged);
                symmetricKey = new System.Security.Cryptography.RijndaelManaged();
                symmetricKey.Mode = System.Security.Cryptography.CipherMode.CBC;
                System.Security.Cryptography.ICryptoTransform encryptor = default(System.Security.Cryptography.ICryptoTransform);
                encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes);

                System.IO.MemoryStream memoryStream = default(System.IO.MemoryStream);
                memoryStream = new System.IO.MemoryStream();

                System.Security.Cryptography.CryptoStream cryptoStream = default(System.Security.Cryptography.CryptoStream);
                cryptoStream = new System.Security.Cryptography.CryptoStream(memoryStream, encryptor, System.Security.Cryptography.CryptoStreamMode.Write);
                cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);

                cryptoStream.FlushFinalBlock();

                byte[] cipherTextBytes = null;
                cipherTextBytes = memoryStream.ToArray();

                memoryStream.Close();
                cryptoStream.Close();

                string cipherText = null;
                cipherText = Convert.ToBase64String(cipherTextBytes);

                strReturn = cipherText;
            }
            catch (Exception ex)
            {
                strReturn = null;
            }
            return strReturn;
        }

My Question is, how can I put Decrypt(connString) on the SQL DataSource while the SQL Data Source in html source?

Thank you.

Answer 1

You need to use a custom ExpressionBuilder to achieve this.

Steps:

1. Define a custom class:

   [ExpressionPrefix("MyConnectionExpression")] [ExpressionEditor("MyConnectionExpressionEditor")] public class MyConnectionStringExpressionBuilder : ExpressionBuilder { }

Refer to this: http://msdn.microsoft.com/en-us/library/system.web.compilation.expressionbuilder(v=vs.110).aspx

1. In that sample, instead of the GetEvalData method, use your method which does the following:

Reads the encrypted connection string from the config file. Uses your Decrypt method and returns the data as an object.

1. ensure you update your web.config with this custom expression builder details.

then you can start using the Expression builder.