The GV module in Ginesys is creates GV numbers serially. Anyone can duplicate the physical card with a serial no. and can redeem it. Chances are 1 in 100, but very much possible in case of GV sold through HO as those are all sold/issued at one go.
Requirement is along with Serial GV Number there should be a random no. Both has to be validated while redeeming. Solves the issue and OTP isn't a option.
Guest
The purpose of GV sale is to gift those vouchers to customer's friends & family. While redeeming, any random password / key generated are being verified that will be attached with buyers mobile no. Hence, the person who's a valid redeemer will not be able to use it for further purchase.
Marking this as will not implement. We appreciate your effort. Keep posting.
Random No. should be printed on GV.
As a continuous series can be tampered by an un-authorized person as in Ginesys GV No come in a continuous series.