如何用c#加密/保护MS Access 2007数据库文件

我有一个程序，让我访问/添加/删除条目从MS access 2007文件使用一个简单的数据库密码。

但我的目标是修改我的文件，使其更安全。我想加密我的文件，如果可能的话，使用用户选择的加密，并且只有在用户提供正确的用户名和密码时才能访问。

我该怎么做呢?如何加密文件?如何使用户能够进行身份验证?

请具体说明，最好是傻瓜的例子:)

编辑:如果我使用AES加密文件中的每个条目，会更安全吗?我应该这样做，让数据库文件没有密码吗?

这是我现在访问文件的方式:

// May be public so we can display
// content of file from different forms.
public void DisplayFileContent(string filePath)
{
    // Creating an object allowing me connecting to the database.
    OleDbConnection objOleDbConnection = new OleDbConnection();
    // Creating command object.
    objOleDbConnection.ConnectionString =
        "Provider=Microsoft.ACE.OLEDB.12.0;" +
        "Data Source=" + filePath + ";" +
        "Persist Security Info=False;" +
        "Jet OLEDB:Database Password=" + storedAuth.Password + ";";
    OleDbCommand objOleDbCommand = new OleDbCommand();
    objOleDbCommand.Connection = objOleDbConnection;
    objOleDbCommand.CommandText = "Select * FROM PersonalData";
    // Create a data reader.
    OleDbDataReader readPersonalData;
    try
    {
        // Open database connection.
        objOleDbConnection.Open();
        // Associate data reader with the command.
        readPersonalData = objOleDbCommand.ExecuteReader();
        // Counting all entries.
        int countEntries = 0;
        // Clearing the textbox before proceeding.
        txtDisplay.Text = string.Empty;
        if (readPersonalData.HasRows)
        {
            while (readPersonalData.Read())
            {
                // Count all entries read from the reader.
                countEntries++;
                txtDisplay.Text += "=== Entry ID: " + readPersonalData.GetValue(0) + " ===" + Environment.NewLine;
                txtDisplay.Text += "Type: " + readPersonalData.GetValue(1) + Environment.NewLine;
                if (!readPersonalData.IsDBNull(2)) txtDisplay.Text += "URL: " + readPersonalData.GetValue(2) + Environment.NewLine;
                if (!readPersonalData.IsDBNull(3)) txtDisplay.Text += "Software Name: " + readPersonalData.GetValue(3) + Environment.NewLine;
                if (!readPersonalData.IsDBNull(4)) txtDisplay.Text += "Serial Code: " + readPersonalData.GetValue(4) + Environment.NewLine;
                if (!readPersonalData.IsDBNull(5)) txtDisplay.Text += "User Name: " + readPersonalData.GetValue(5) + Environment.NewLine;
                if (!readPersonalData.IsDBNull(6)) txtDisplay.Text += "Password: " + readPersonalData.GetValue(6) + Environment.NewLine;
                txtDisplay.Text += Environment.NewLine;
            }
        }
        else
        {
            txtDisplay.Text = "There is nothing to display! You must add something so I can display something here.";
        }
        // Displaying number of entries in the status bar.
        tsslStatus.Text = "A total of " + countEntries + " entries.";
        // Selecting 0 character to make sure text
        // isn't completly selected.
        txtDisplay.SelectionStart = 0;
    }

My EncryptDecrypt.cs file:

using System;
using System.IO;
using System.Text;
using System.Security.Cryptography;
namespace Password_Manager
{
    class EncryptDecrypt
    {
        string input, userName, password;
        RijndaelManaged Crypto = new RijndaelManaged();
        public EncryptDecrypt()
        {
        }
        public EncryptDecrypt(string input, string userName, string password)
        {
            this.input = input;
            this.userName = userName;
            this.password = password;
        }
        public string Encrypt(string PlainText, string pass, string usrName)
        {
            string HashAlgorithm = "SHA1"; 
            int PasswordIterations = 2;
            string InitialVector = "OFRna73m*aze01xY";
            int KeySize = 256;
            this.input = PlainText;
            if (string.IsNullOrEmpty(PlainText))
                return "";
            byte[] InitialVectorBytes = Encoding.ASCII.GetBytes(InitialVector);
            byte[] SaltValueBytes = Encoding.ASCII.GetBytes(usrName);
            byte[] PlainTextBytes = Encoding.UTF8.GetBytes(PlainText);
            PasswordDeriveBytes DerivedPassword = new PasswordDeriveBytes(pass, SaltValueBytes, HashAlgorithm, PasswordIterations);
            byte[] KeyBytes = DerivedPassword.GetBytes(KeySize / 8);
            RijndaelManaged SymmetricKey = new RijndaelManaged();
            SymmetricKey.Mode = CipherMode.CBC;
            byte[] CipherTextBytes = null;
            using (ICryptoTransform Encryptor = SymmetricKey.CreateEncryptor(KeyBytes, InitialVectorBytes))
            {
                using (MemoryStream MemStream = new MemoryStream())
                {
                    using (CryptoStream CryptoStream = new CryptoStream(MemStream, Encryptor, CryptoStreamMode.Write))
                    {
                        CryptoStream.Write(PlainTextBytes, 0, PlainTextBytes.Length);
                        CryptoStream.FlushFinalBlock();
                        CipherTextBytes = MemStream.ToArray();
                        MemStream.Close();
                        CryptoStream.Close();
                    }
                }
            }
            SymmetricKey.Clear();
            return Convert.ToBase64String(CipherTextBytes);
        }
        public string Decrypt(string CipherText, string pass, string usrName)
        {
            string HashAlgorithm = "SHA1"; 
            int PasswordIterations = 2;
            string InitialVector = "OFRna73m*aze01xY";
            int KeySize = 256;
             if (string.IsNullOrEmpty(CipherText))
                 return "";
             byte[] InitialVectorBytes = Encoding.ASCII.GetBytes(InitialVector);
             byte[] SaltValueBytes = Encoding.ASCII.GetBytes(usrName);
             byte[] CipherTextBytes = Convert.FromBase64String(CipherText);
             PasswordDeriveBytes DerivedPassword = new PasswordDeriveBytes(pass, SaltValueBytes, HashAlgorithm, PasswordIterations);
             byte[] KeyBytes = DerivedPassword.GetBytes(KeySize / 8);
             RijndaelManaged SymmetricKey = new RijndaelManaged();
             SymmetricKey.Mode = CipherMode.CBC;
             byte[] PlainTextBytes = new byte[CipherTextBytes.Length];
             int ByteCount = 0;
             using (ICryptoTransform Decryptor = SymmetricKey.CreateDecryptor(KeyBytes, InitialVectorBytes))
             {
                 using (MemoryStream MemStream = new MemoryStream(CipherTextBytes))
                 {
                     using (CryptoStream CryptoStream = new CryptoStream(MemStream, Decryptor, CryptoStreamMode.Read))
                     {
                         ByteCount = CryptoStream.Read(PlainTextBytes, 0, PlainTextBytes.Length);
                         MemStream.Close();
                         CryptoStream.Close();
                     }
                 }
             }
             SymmetricKey.Clear();
             return Encoding.UTF8.GetString(PlainTextBytes, 0, ByteCount);
         }
    }
}