/// <summary>
/// Converts the value of the current <see cref="SecureSymmetricKey" /> to its equivalent binary representation.
/// </summary>
/// <returns>
/// A binary representation of the current <see cref="SecureSymmetricKey" />.
/// </returns>
public SecureBuffer ToBuffer()
{
var resultBuffer = new SecureBuffer(SerializedLength);
try
{
using (var controlToken = StateControl.Enter())
{
using (var plaintextBuffer = new PinnedBuffer(SerializedPlaintextLength, true))
{
KeySource.Access(pinnedKeySourceBuffer =>
{
Array.Copy(pinnedKeySourceBuffer, 0, plaintextBuffer, KeySourceBufferIndex, KeySourceLengthInBytes);
});
plaintextBuffer[AlgorithmBufferIndex] = (Byte)Algorithm;
plaintextBuffer[DerivationModeBufferIndex] = (Byte)DerivationMode;
using (var cipher = BufferEncryptionAlgorithm.ToCipher(RandomnessProvider))
{
using (var initializationVector = new PinnedBuffer(cipher.BlockSizeInBytes, true))
{
RandomnessProvider.GetBytes(initializationVector);
resultBuffer.Access(pinnedResultBuffer =>
{
using (var ciphertext = cipher.Encrypt(plaintextBuffer, BufferEncryptionKey, initializationVector))
{
Array.Copy(ciphertext, 0, pinnedResultBuffer, 0, SerializedLength);
}
});
}
}
}
}
return(resultBuffer);
}
catch
{
resultBuffer.Dispose();
throw new SecurityException("Key serialization failed.");
}
}
/// <summary>
/// Creates a new instance of a <see cref="SecureSymmetricKey" /> using the specified buffer.
/// </summary>
/// <param name="buffer">
/// A binary representation of a <see cref="SecureSymmetricKey" />.
/// </param>
/// <returns>
/// A new instance of a <see cref="SecureSymmetricKey" />.
/// </returns>
/// <exception cref="ArgumentException">
/// <paramref name="buffer" /> is invalid.
/// </exception>
/// <exception cref="ArgumentNullException">
/// <paramref name="buffer" /> is <see langword="null" />.
/// </exception>
public static SecureSymmetricKey FromBuffer(SecureBuffer buffer)
{
buffer.RejectIf().IsNull(nameof(buffer)).OrIf(argument => argument.Length != SerializedLength, nameof(buffer), "The specified buffer is invalid.");
try
{
var result = (SecureSymmetricKey)null;
buffer.Access(pinnedCiphertext =>
{
using (var plaintextBuffer = new PinnedBuffer(SerializedPlaintextLength, true))
{
using (var cipher = BufferEncryptionAlgorithm.ToCipher(RandomnessProvider))
{
using (var plaintext = cipher.Decrypt(pinnedCiphertext, BufferEncryptionKey))
{
Array.Copy(plaintext, 0, plaintextBuffer, 0, SerializedPlaintextLength);
}
}
using (var keySource = new PinnedBuffer(KeySourceLengthInBytes, true))
{
Array.Copy(plaintextBuffer, KeySourceBufferIndex, keySource, 0, KeySourceLengthInBytes);
var algorithm = (SymmetricAlgorithmSpecification)plaintextBuffer[AlgorithmBufferIndex];
var derivationMode = (SecureSymmetricKeyDerivationMode)plaintextBuffer[DerivationModeBufferIndex];
result = new SecureSymmetricKey(algorithm, derivationMode, keySource);
}
}
});
return(result);
}
catch
{
throw new ArgumentException("The specified buffer is invalid.", nameof(buffer));
}
}
