Figure out which .proto for a message

Question

I have a sample of a ProtoBuf encoded message, as well as all of the .proto files. I know that the message is one of the messages in the proto files. Is there some way to figure out which message fits the encoded message?

Answer 1

In general, no. The protobuf format is dense, and the same bytes may be valid as two different kinds of messages.

That said, you can pipe the message to protoc --decode_raw to see the content with numeric tags. From there, you might be able to manually compare it against each type to decide whether it makes sense as that type.