/// <summary>
/// This takes the given message and verifies it using SSPI(VerifySignature). The given message
/// should be formatted as follow:
/// |MESSAGE_LENGTH(4 bytes)|MESSAGE
/// </summary>
/// <param name="messageToBeVerified">Signed message to be verified</param>
/// <param name="signature">Signature</param>
/// <returns>If true, verify successful, otherwise failed.</returns>
/// <exception cref="SspiException">If verify fail, this exception will be thrown.</exception>
/// <exception cref="ArgumentNullException">If messageToBeVerified is null, this exception will be thrown.
/// </exception>
/// <exception cref="ArgumentException">If messageToBeVerified is not formatted as
/// "MESSAGE_LENGTH(4 bytes)|MESSAGE", this exception will be thrown.</exception>
public bool VerifyMessage(byte[] messageToBeVerified, byte[] signature)
{
if (!SspiUtility.VerifyMessageHeader(messageToBeVerified))
{
throw new ArgumentException(
"Value of message header is not consistent with the actual length of message.",
"messageToBeVerified");
}
//Remove header.
byte[] messageBody = new byte[messageToBeVerified.Length - sizeof(int)];
Array.Copy(messageToBeVerified, sizeof(int), messageBody, 0, messageBody.Length);
return(Verify(messageBody, signature));
}
/// <summary>
/// Decrypts the encrypted message(contains message header) and returns decrypted message.
/// Schannel is not supported.
/// The given message must be formatted as follow:
/// MESSAGE_LENGTH(4 bytes)|MESSAGE
/// </summary>
/// <param name="messageToBeDecrypted">Message to be decrypted</param>
/// <returns>Decrypted message</returns>
/// <exception cref="ArgumentNullException">If messageToBeDecrypted is null, this exception will be thrown.
/// </exception>
/// <exception cref="ArgumentException">If messageToBeDecrypted is not formatted as
/// "MESSAGE_LENGTH(4 bytes)|MESSAGE", this exception will be thrown.</exception>
public byte[] DecryptMessage(byte[] messageToBeDecrypted)
{
if (!SspiUtility.VerifyMessageHeader(messageToBeDecrypted))
{
throw new ArgumentException(
"Value of message header is not consistent with the actual length of message.",
"messageToBeDecrypted");
}
//Remove message header
int messageLength = BitConverter.ToInt32(messageToBeDecrypted, 0);
byte[] message = ArrayUtility.SubArray(messageToBeDecrypted, sizeof(int), messageLength);
byte[] signature = ArrayUtility.SubArray(messageToBeDecrypted, sizeof(int) + messageLength);
return(Decrypt(message, signature));
}
