Code Snip Colletion "Encrypting and Decrypting"
This class is just a code snip to encrypt and decrypt an string. Very handly to keep around. on the static string sKey, please do change it to something unique for you, otherwise anybody will be able to decrypt your encrypted stuff.
public class AlEncrypt
{
private static string sKey = "al%&is($awesome^ohyes$!too*whois)better**than(Albert!";
public static string Encrypt(string sPainText)
{
if (sPainText.Length == 0)
return (sPainText);
return (EncryptString(sPainText, sKey));
}
public static string Decrypt(string sEncryptText)
{
if (sEncryptText.Length == 0)
return (sEncryptText);
return (DecryptString(sEncryptText, sKey));
}
protected static string EncryptString(string InputText, string Password)
{
// "Password" string variable is nothing but the key(your secret key) value which is sent from the front end.
// "InputText" string variable is the actual password sent from the login page.
// We are now going to create an instance of the
// Rihndael class.
RijndaelManaged RijndaelCipher = new RijndaelManaged();
// First we need to turn the input strings into a byte array.
byte[] PlainText = System.Text.Encoding.Unicode.GetBytes(InputText);
// We are using Salt to make it harder to guess our key
// using a dictionary attack.
byte[] Salt = Encoding.ASCII.GetBytes(Password.Length.ToString());
// The (Secret Key) will be generated from the specified
// password and Salt.
//PasswordDeriveBytes -- It Derives a key from a password
PasswordDeriveBytes SecretKey = new PasswordDeriveBytes(Password, Salt);
// Create a encryptor from the existing SecretKey bytes.
// We use 32 bytes for the secret key
// (the default Rijndael key length is 256 bit = 32 bytes) and
// then 16 bytes for the IV (initialization vector),
// (the default Rijndael IV length is 128 bit = 16 bytes)
ICryptoTransform Encryptor = RijndaelCipher.CreateEncryptor(SecretKey.GetBytes(16), SecretKey.GetBytes(16));
// Create a MemoryStream that is going to hold the encrypted bytes
MemoryStream memoryStream = new MemoryStream();
// Create a CryptoStream through which we are going to be processing our data.
// CryptoStreamMode.Write means that we are going to be writing data
// to the stream and the output will be written in the MemoryStream
// we have provided. (always use write mode for encryption)
CryptoStream cryptoStream = new CryptoStream(memoryStream, Encryptor, CryptoStreamMode.Write);
// Start the encryption process.
cryptoStream.Write(PlainText, 0, PlainText.Length);
// Finish encrypting.
cryptoStream.FlushFinalBlock();
// Convert our encrypted data from a memoryStream into a byte array.
byte[] CipherBytes = memoryStream.ToArray();
// Close both streams.
memoryStream.Close();
cryptoStream.Close();
// Convert encrypted data into a base64-encoded string.
// A common mistake would be to use an Encoding class for that.
// It does not work, because not all byte values can be
// represented by characters. We are going to be using Base64 encoding
// That is designed exactly for what we are trying to do.
string EncryptedData = Convert.ToBase64String(CipherBytes);
// Return encrypted string.
return EncryptedData;
}
protected static string DecryptString(string InputText, string Password)
{
RijndaelManaged RijndaelCipher = new RijndaelManaged();
byte[] EncryptedData = Convert.FromBase64String(InputText);
byte[] Salt = Encoding.ASCII.GetBytes(Password.Length.ToString());
PasswordDeriveBytes SecretKey = new PasswordDeriveBytes(Password, Salt);
// Create a decryptor from the existing SecretKey bytes.
ICryptoTransform Decryptor = RijndaelCipher.CreateDecryptor(SecretKey.GetBytes(16), SecretKey.GetBytes(16));
MemoryStream memoryStream = new MemoryStream(EncryptedData);
// Create a CryptoStream. (always use Read mode for decryption).
CryptoStream cryptoStream = new CryptoStream(memoryStream, Decryptor, CryptoStreamMode.Read);
// Since at this point we don't know what the size of decrypted data
// will be, allocate the buffer long enough to hold EncryptedData;
// DecryptedData is never longer than EncryptedData.
byte[] PlainText = new byte[EncryptedData.Length];
// Start decrypting.
int DecryptedCount = cryptoStream.Read(PlainText, 0, PlainText.Length);
memoryStream.Close();
cryptoStream.Close();
// Convert decrypted data into a string.
string DecryptedData = Encoding.Unicode.GetString(PlainText, 0, DecryptedCount);
// Return decrypted string.
return DecryptedData;
}
}