I have created a few little programs that export data to a text file using StreamWriter and then I read them back in using StreamReader. This works great and does what I need it to do but I was wondering if there was a way that I could save this information without the user being able to access or modify it either intentionally or unintentionally. An example of something I would have in a text file would be if a checkbox was ticked, when you tick it it outputs "Ticked" to a text file, when the program is re - opened I know what state the form was in when it was closed. I obviously don't want to keep using text files. Does anyone have any ideas on how I can easily store this information without the user being able to modify it? Thank you very much.
The simplest way is to Base-64 encode/decode this text. This is not secure, but will prevent a casual user from modifying the data.
static public string EncodeTo64(string toEncode)
{
byte[] toEncodeAsBytes
= System.Text.ASCIIEncoding.ASCII.GetBytes(toEncode);
string returnValue
= System.Convert.ToBase64String(toEncodeAsBytes);
return returnValue;
}
static public string DecodeFrom64(string encodedData)
{
byte[] encodedDataAsBytes
= System.Convert.FromBase64String(encodedData);
string returnValue =
System.Text.ASCIIEncoding.ASCII.GetString(encodedDataAsBytes);
return returnValue;
}
EDIT: Real encryption
#region Encryption
string passPhrase = "Pasword"; // can be any string
string saltValue = "sALtValue"; // can be any string
string hashAlgorithm = "SHA1"; // can be "MD5"
int passwordIterations = 7; // can be any number
string initVector = "~1B2c3D4e5F6g7H8"; // must be 16 bytes
int keySize = 256; // can be 192 or 128
private string Encrypt(string data)
{
byte[] bytes = Encoding.ASCII.GetBytes(this.initVector);
byte[] rgbSalt = Encoding.ASCII.GetBytes(this.saltValue);
byte[] buffer = Encoding.UTF8.GetBytes(data);
byte[] rgbKey = new PasswordDeriveBytes(this.passPhrase, rgbSalt, this.hashAlgorithm, this.passwordIterations).GetBytes(this.keySize / 8);
RijndaelManaged managed = new RijndaelManaged();
managed.Mode = CipherMode.CBC;
ICryptoTransform transform = managed.CreateEncryptor(rgbKey, bytes);
MemoryStream stream = new MemoryStream();
CryptoStream stream2 = new CryptoStream(stream, transform, CryptoStreamMode.Write);
stream2.Write(buffer, 0, buffer.Length);
stream2.FlushFinalBlock();
byte[] inArray = stream.ToArray();
stream.Close();
stream2.Close();
return Convert.ToBase64String(inArray);
}
private string Decrypt(string data)
{
byte[] bytes = Encoding.ASCII.GetBytes(this.initVector);
byte[] rgbSalt = Encoding.ASCII.GetBytes(this.saltValue);
byte[] buffer = Convert.FromBase64String(data);
byte[] rgbKey = new PasswordDeriveBytes(this.passPhrase, rgbSalt, this.hashAlgorithm, this.passwordIterations).GetBytes(this.keySize / 8);
RijndaelManaged managed = new RijndaelManaged();
managed.Mode = CipherMode.CBC;
ICryptoTransform transform = managed.CreateDecryptor(rgbKey, bytes);
MemoryStream stream = new MemoryStream(buffer);
CryptoStream stream2 = new CryptoStream(stream, transform, CryptoStreamMode.Read);
byte[] buffer5 = new byte[buffer.Length];
int count = stream2.Read(buffer5, 0, buffer5.Length);
stream.Close();
stream2.Close();
return Encoding.UTF8.GetString(buffer5, 0, count);
}
#endregion