In all applications password encryption and decryption is must.
For the security reasons that you wanted to encypt your password or sensitive data before storing it to the database and decypt after pulling it from the database using ASP.NET C#.
Here is two simple method on how to encrypt and decrypt password:
In the code behind (aspx.cs) page, use the following code:
Button click event( for user registration ) :
protected void btnSignin_Click(object sender, ImageClickEventArgs e)
{
string plainText = txtPassword.Text;
string passPhrase = "Pas5@se"; // can be any string
string saltValue = "@1Value"; // can be any string
string hashAlgorithm = "SHA1"; // can be "MD5"
int passwordIterations = 2; // can be any number
string initVector = "@1B2c3D4e5F6g7H8"; // must be 16 bytes
int keySize = 256; // can be 192 or 128
string cipherText = Encrypt(plainText, passPhrase, saltValue, hashAlgorithm, passwordIterations, initVector, keySize);
}
Calling Encrypt Method :
public static string Encrypt(string plainText, string passPhrase, string saltValue, string hashAlgorithm, int passwordIterations, string initVector, int keySize)
{
byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector);
byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue);
byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);
PasswordDeriveBytes password = new PasswordDeriveBytes(
passPhrase,
saltValueBytes,
hashAlgorithm,
passwordIterations);
byte[] keyBytes = password.GetBytes(keySize / 8);
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
ICryptoTransform encryptor = symmetricKey.CreateEncryptor(
keyBytes,
initVectorBytes);
MemoryStream memoryStream = new MemoryStream();
CryptoStream cryptoStream = new CryptoStream(memoryStream,
encryptor,
CryptoStreamMode.Write);
// Start encrypting.
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
// Finish encrypting.
cryptoStream.FlushFinalBlock();
// Convert our encrypted data from a memory stream into a byte array.
byte[] cipherTextBytes = memoryStream.ToArray();
// Close both streams.
memoryStream.Close();
cryptoStream.Close();
// Convert encrypted data into a base64-encoded string.
string cipherText = Convert.ToBase64String(cipherTextBytes);
// Return encrypted string.
return cipherText;
}
Decryption method ( forget password) :
if user forgot his password, by using decryption method , we get the password and send mail to the user.
public static string Decrypt(string cipherText, string passPhrase, string saltValue, string hashAlgorithm, int passwordIterations, string initVector, int keySize)
{
// Convert strings defining encryption key characteristics into byte
// arrays. Let us assume that strings only contain ASCII codes.
// If strings include Unicode characters, use Unicode, UTF7, or UTF8
// encoding.
byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector);
byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue);
// Convert our ciphertext into a byte array.
byte[] cipherTextBytes = Convert.FromBase64String(cipherText);
// First, we must create a password, from which the key will be
// derived. This password will be generated from the specified
// passphrase and salt value. The password will be created using
// the specified hash algorithm. Password creation can be done in
// several iterations.
PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, saltValueBytes, hashAlgorithm, passwordIterations);
// Use the password to generate pseudo-random bytes for the encryption
// key. Specify the size of the key in bytes (instead of bits).
byte[] keyBytes = password.GetBytes(keySize / 8);
// Create uninitialized Rijndael encryption object.
RijndaelManaged symmetricKey = new RijndaelManaged();
// It is reasonable to set encryption mode to Cipher Block Chaining
// (CBC). Use default options for other symmetric key parameters.
symmetricKey.Mode = CipherMode.CBC;
// Generate decryptor from the existing key bytes and initialization
// vector. Key size will be defined based on the number of the key
// bytes.
ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes);
// Define memory stream which will be used to hold encrypted data.
MemoryStream memoryStream = new MemoryStream(cipherTextBytes);
// Define cryptographic stream (always use Read mode for encryption).
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 ciphertext;
// plaintext is never longer than ciphertext.
byte[] plainTextBytes = new byte[cipherTextBytes.Length];
// Start decrypting.
int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
// Close both streams.
memoryStream.Close();
cryptoStream.Close();
// Convert decrypted data into a string.
// Let us assume that the original plaintext string was UTF8-encoded.
string plainText = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
// Return decrypted string.
return plainText;
}
