/// <summary>
/// Use this to sign a <see cref="ProtocolMessage"/> before sending it.
/// If a signature was found on the message, this will error.
/// </summary>
/// <param name="protocolMessage">The message that needs to be signed.</param>
/// <param name="keySigner">An instance of <see cref="IKeySigner"/> used to build the signature.</param>
/// <param name="signingContext">The context used to sign the message.</param>
public static ProtocolMessage Sign(this ProtocolMessage protocolMessage,
IKeySigner keySigner,
SigningContext signingContext)
{
if ((protocolMessage.Signature?.RawBytes.Length ?? 0) == keySigner.CryptoContext.SignatureLength)
{
Logger.Debug("The protocol message was already signed, returning a clone.");
return(protocolMessage.Clone());
}
protocolMessage.Signature = null;
var signatureBytes = keySigner.Sign(protocolMessage.ToByteArray(),
signingContext).SignatureBytes;
var signature = new Signature
{
SigningContext = signingContext,
RawBytes = signatureBytes.ToByteString()
};
protocolMessage.Signature = signature;
return(protocolMessage);
}
