In the past, I've successfully created java LTI Tool Providers (using Blackboard's BLTI-Sandwich) which have been working nicely for a few years. The TPs are an integral part of our BB courses, and are called from many places.
Now I'm trying to create a java-based LTI Tool Consumer with the same library, but the signature process doesn't seem to be working.
BLTIMessage msg = new BLTIMessage( "ConsumerKey" );
// fill in parameters...
BLTIConsumer consumer = new BLTIConsumer( "POST", launchsite,msg );
List<Map.Entry<String, String>> launchParams = consumer.getParameters();
// then autopost a form with the parameters embedded.
The error on the TP webserver is:
(I've double checked everything, and can connect to the TP from other TCs, including Blackboard).