Reduce complexity by factoring out keyshare check

Author: konradkonrad

rolling-shutter/keyper/epochkghandler/keyshare.go

@@ -76,6 +76,12 @@ func (handler *DecryptionKeyShareHandler) ValidateMessage(ctx context.Context, m
 	if len(keyShare.Shares) > int(handler.config.GetMaxNumKeysPerMessage()) {
 		return pubsub.ValidationReject, errors.Errorf("too many key shares in message (%d > %d)", len(keyShare.Shares), handler.config.GetMaxNumKeysPerMessage())
 	}
+
+	validationResult, err := checkKeyShares(keyShare, pureDKGResult)
+	return validationResult, err
+}
+
+func checkKeyShares(keyShare *p2pmsg.DecryptionKeyShares, pureDKGResult *puredkg.Result) (pubsub.ValidationResult, error) {
 	shares := keyShare.GetShares()
 	for i, share := range shares {
 		epochSecretKeyShare, err := share.GetEpochSecretKeyShare()