// Supress warnings due to .NET 3.5 compatibility
// ReSharper disable SuspiciousTypeConversion.Global
#pragma warning disable S1944 // Inappropriate casts should not be made
private static DeriveResult DeriveBytes(string key)
{
var deriver = new Rfc2898DeriveBytes(key, SaltSize);
var result = new DeriveResult
{
Salt = deriver.Salt,
Key = deriver.GetBytes(32),
InitializationVector = deriver.GetBytes(16)
};
(deriver as IDisposable)?.Dispose();
return(result);
}
private static DeriveResult DeriveBytes(string key, byte[] saltBytes)
{
var deriver = new Rfc2898DeriveBytes(key, saltBytes);
// Derive the previous IV from the Key and Salt
var result = new DeriveResult
{
Key = deriver.GetBytes(32),
InitializationVector = deriver.GetBytes(16)
};
(deriver as IDisposable)?.Dispose();
return(result);
}
private static string DecryptStream(byte[] cipher, DeriveResult keys)
{
// Create a decrytor to perform the stream transform.
// Create the streams used for decryption.
// The default Cipher Mode is CBC and the Padding is PKCS7 which are both good
using (var aesManaged = new AesManaged())
using (var decryptor = aesManaged.CreateDecryptor(keys.Key, keys.InitializationVector))
using (var memoryStream = new MemoryStream(cipher))
using (var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
using (var streamReader = new StreamReader(cryptoStream))
{
// Return the decrypted keys from the decrypting stream.
return(streamReader.ReadToEnd());
}
}
private static byte[] EncryptStream(string clearText, DeriveResult bytes)
{
// Create an encryptor to perform the stream transform.
// Create the streams used for encryption.
using (var aesManaged = new AesManaged())
using (var encryptor = aesManaged.CreateEncryptor(bytes.Key, bytes.InitializationVector))
using (var memoryStream = new MemoryStream())
{
using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
using (var streamWriter = new StreamWriter(cryptoStream))
{
// Send the data through the StreamWriter, through the CryptoStream, to the underlying MemoryStream
streamWriter.Write(clearText);
// vv Have to dispose of the SW here in order to maintain the integrity of the memoryStream.
}
// Return the encrypted keys from the memory stream, in Base64 form so we can send it right to a database (if we want).
var cipherTextBytes = memoryStream.ToArray();
return(cipherTextBytes);
}
}
