Fix key and key share order check

Key and key shares in p2p messages are ordered according the the
corresponding identity preimage. We used to check that they are strictly
ordered which disallows duplicates. However, at least in Shutterized
Gnosis Chain, duplicates are possible. We fix this by allowing
duplicates.

Author: jannikluhn

rolling-shutter/keyper/epochkghandler/key.go

@@ -77,7 +77,7 @@ func (handler *DecryptionKeyHandler) ValidateMessage(ctx context.Context, msg p2
 			return pubsub.ValidationReject, errors.Errorf("epoch secret key for identity %x is not valid", k.Identity)
 		}
 
-		if i > 0 && bytes.Compare(k.Identity, key.Keys[i-1].Identity) != 1 {
+		if i > 0 && bytes.Compare(k.Identity, key.Keys[i-1].Identity) < 0 {
 			return pubsub.ValidationReject, errors.Errorf("keys not ordered")
 		}
 	}

rolling-shutter/keyper/epochkghandler/keyshare.go

@@ -80,7 +80,7 @@ func (handler *DecryptionKeyShareHandler) ValidateMessage(ctx context.Context, m
 			return pubsub.ValidationReject, errors.Errorf("cannot verify secret key share")
 		}
 
-		if i > 0 && bytes.Compare(share.EpochID, shares[i-1].EpochID) != 1 {
+		if i > 0 && bytes.Compare(share.EpochID, shares[i-1].EpochID) < 0 {
 			return pubsub.ValidationReject, errors.Errorf("keyshares not ordered")
 		}
 	}