DO NOT MERGE: Add a checker for signature boundary in verifier am: f616da1726 am: 5346da0220  -s ours am: a41cc29447  -s ours am: 051dfa7ec3  -s ours am: 94c8b5e5a6 am: 2b1bcab427  -s ours am: 37a5941440 am: ddca75fb0a
am: b21b92b386

Change-Id: I30cc5605866bc087fc6afdad2b2d7e033cd2f25e