Encryption Decryption - ASP .Net , C#

Decryption Code

string passPhrase = "DevNetCor"; // can be any string
string saltValue = "test@key"; // can be any string
string hashAlgorithm = "MD5"; // 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

// 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 = System.Text.Encoding.ASCII.GetBytes(initVector);
byte[] saltValueBytes = System.Text.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.
cipherText = System.Text.Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);



--------Encryption Code

string passPhrase = "DevNetCor"; // can be any string
string saltValue = "test@key"; // can be any string
string hashAlgorithm = "MD5"; // 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


// Convert strings 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 = System.Text.Encoding.ASCII.GetBytes(initVector);
byte[] saltValueBytes = System.Text.Encoding.ASCII.GetBytes(saltValue);

// Convert our plaintext into a byte array.
// Let us assume that plaintext contains UTF8-encoded characters.
byte[] plainTextBytes = System.Text.Encoding.UTF8.GetBytes(plainText);

// 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 encryptor from the existing key bytes and initialization
// vector. Key size will be defined based on the number of the key
// bytes.
ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes);

// Define memory stream which will be used to hold encrypted data.
MemoryStream memoryStream = new MemoryStream();

// Define cryptographic stream (always use Write mode for encryption).
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.
plainText = Convert.ToBase64String(cipherTextBytes);