2.2 on page 10 says "... proving that the discrete log of two values is identical in zero knowledge" without ever defining discrete log and zero knowledge proofs. The authors say that their construction is built on Chaum-Pedersen proof, but no further details are provided.
2.2.1 on page 11 ends the description of GenerateProof without ever describing why the output of the function [c , s] is a discrete log equivalence proof and why is it zero knowledge.
2.1 on page 8 starts talking about groups and then suddenly mentions finite fields without explaining what they are. It becomes clear reading further down that the authors need them for scalars. It would have been less confusing if they simply used the set of integers {0, 1, ..., p-1}.
It addresses the following items from review