/// <inheritdoc/>
public byte[] Encrypt(
byte[] message,
SecureString password,
KeyDerivationCostType costType,
string encryptorName,
string kdfName = Pbkdf2.CryptoKdfName,
string compression = null)
{
if (message == null)
{
throw new ArgumentNullException(nameof(message));
}
ValidatePassword(password);
if (_randomSource == null)
{
throw new ArgumentNullException(nameof(_randomSource));
}
if (string.IsNullOrWhiteSpace(encryptorName))
{
encryptorName = BouncyCastleXChaCha20.CryptoAlgorithmName;
}
if (string.IsNullOrWhiteSpace(kdfName))
{
encryptorName = Pbkdf2.CryptoKdfName;
}
ISymmetricEncryptionAlgorithm encryptor = new SymmetricEncryptionAlgorithmFactory().CreateAlgorithm(encryptorName);
IKeyDerivationFunction kdf = new KeyDerivationFactory().CreateKdf(kdfName);
// Prepare header
CryptoHeader header = new CryptoHeader();
header.PackageName = PackageName;
header.AlgorithmName = encryptor.Name;
header.Nonce = _randomSource.GetRandomBytes(encryptor.ExpectedNonceSize);
header.KdfName = kdf.Name;
header.Salt = _randomSource.GetRandomBytes(kdf.ExpectedSaltSizeBytes);
int cost = kdf.RecommendedCost(costType);
header.Cost = cost.ToString();
header.Compression = compression;
try
{
if (string.Equals(CompressionGzip, header.Compression, StringComparison.InvariantCultureIgnoreCase))
{
message = CompressUtils.Compress(message);
}
byte[] key = kdf.DeriveKeyFromPassword(password, encryptor.ExpectedKeySize, header.Salt, cost);
byte[] cipher = encryptor.Encrypt(message, key, header.Nonce);
return(CryptoHeaderPacker.PackHeaderAndCypher(header, cipher));
}
catch (Exception ex)
{
throw new CryptoException("An unexpected error occured, while encrypting the message.", ex);
}
}
/// <summary>
/// Encrypts a message with a user password, and adds a header containing all information
/// necessary for the decryption (algorithm, nonce, salt, ...).
/// </summary>
/// <param name="message">Plain text message to encrypt.</param>
/// <param name="password">Password to use for encryption, minimum length is 7 characters.</param>
/// <param name="costType">The cost type to use for encryption.</param>
/// <param name="randomSource">A cryptographically safe random source.</param>
/// <param name="encryptorName">The name of an encryption algorithm which shall be used to
/// do the encryption.</param>
/// <param name="kdfName">The name of a key derivation function, which can convert the
/// password to a key.</param>
/// <returns>A binary array containing the cipher.</returns>
public byte[] Encrypt(
byte[] message,
string password,
KeyDerivationCostType costType,
ICryptoRandomSource randomSource,
string encryptorName,
string kdfName = Pbkdf2.CryptoKdfName)
{
if (message == null)
{
throw new ArgumentNullException("message");
}
ValidatePassword(password);
if (randomSource == null)
{
throw new ArgumentNullException("randomSource");
}
if (string.IsNullOrWhiteSpace(encryptorName))
{
encryptorName = BouncyCastleAesGcm.CryptoAlgorithmName;
}
if (string.IsNullOrWhiteSpace(kdfName))
{
encryptorName = Pbkdf2.CryptoKdfName;
}
ISymmetricEncryptionAlgorithm encryptor = new SymmetricEncryptionAlgorithmFactory().CreateAlgorithm(encryptorName);
IKeyDerivationFunction kdf = new KeyDerivationFactory().CreateKdf(kdfName);
// Prepare header
CryptoHeader header = new CryptoHeader();
header.AppName = _appName;
header.AlgorithmName = encryptor.Name;
header.Nonce = randomSource.GetRandomBytes(encryptor.ExpectedNonceSize);
header.KdfName = kdf.Name;
header.Salt = randomSource.GetRandomBytes(kdf.ExpectedSaltSizeBytes);
int cost = kdf.RecommendedCost(costType);
header.Cost = cost.ToString();
try
{
byte[] key = kdf.DeriveKeyFromPassword(password, encryptor.ExpectedKeySize, header.Salt, cost);
byte[] cipher = encryptor.Encrypt(message, key, header.Nonce);
return(CryptoHeaderPacker.PackHeaderAndCypher(header, cipher));
}
catch (Exception ex)
{
throw new CryptoException("An unexpected error occured, while encrypting the message.", ex);
}
}
/// <summary>
/// Generates a random string of a given length, using the random source of
/// the operating system.The string contains only safe characters of this
/// alphabet: 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz
/// </summary>
/// <param name="length">Number of characters the string should have.</param>
/// <param name="randomSource">Random generator.</param>
/// <returns>New randomly generated string.</returns>
public static string GenerateRandomBase62String(int length, ICryptoRandomSource randomSource)
{
if (length < 0)
{
throw new ArgumentOutOfRangeException("length");
}
StringBuilder result = new StringBuilder();
int remainingLength = length;
do
{
// We take advantage of the fast base64 encoding
int binaryLength = (int)((remainingLength * 3.0 / 4.0) + 1.0);
byte[] randomBytes = randomSource.GetRandomBytes(binaryLength);
string base64String = Convert.ToBase64String(randomBytes);
// Remove invalid characters
result.Append(base64String);
result.Replace("+", string.Empty);
result.Replace("/", string.Empty);
result.Replace("=", string.Empty);
// If too many characters have been removed, we repeat the procedure
remainingLength = length - result.Length;
}while (remainingLength > 0);
result.Length = length;
return(result.ToString());
}
public void MeasureTime()
{
IKeyDerivationFunction kdf = new Pbkdf2();
ICryptoRandomSource randomSource = CommonMocksAndStubs.CryptoRandomService();
SecureString password = CryptoUtils.StringToSecureString("candidate");
byte[] salt = randomSource.GetRandomBytes(kdf.ExpectedSaltSizeBytes);
int iterations = 10000;
Stopwatch watch = new Stopwatch();
watch.Start();
kdf.DeriveKeyFromPassword(password, 32, salt, iterations);
watch.Stop();
Console.WriteLine("Pbkdf2 time for {0} iterations: {1}ms", iterations, watch.ElapsedMilliseconds);
}
