Add checks for nullptr and exception handling to functions taking keys as input parameters
Examples: src/pke/include/pubkeylp.h: MultiAddPubKeys(), MultiAddEvalKeys(), MultiAddEvalMultKeys(), etc.
Also, there should be checks if std::map::find() returns a valid iterator (MultiAddEvalSumKeys(), MultiAddEvalAutomorphismKeys(), etc.)
Ex: in MultiAddEvalAutomorphismKeys(): "es2->find(it->first)->second" returns a garbage iterator (and a garbage value for "second") if the key is not found.
Edited by Dmitriy Suponitskiy