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> because a user has to be allowed to log into a new device (if they lose their old one) You can solve for that by having short validity of the offline tokens

> because a user has to be allowed to log into a new device (if they lose their old one) You can solve for that by having short validity of the offline tokens on device and having that equal the cool-off period for reclaiming those funds when new device is provisioned. If I had ₹100 unspent tokens in my offline capable device that I lost, and got a new device provisioned the same day, then that ₹100 will show up in my account and be available to load on my device only after, say 7 days, of cooling-off period. In those 7 days, if someone who found your device could spend it and if so you lose it. If you know you are likely to be offline only sporadically for few hours and not for days, you can reduce the validity (and hence cooling-off period) significantly to just 12 or 24 hours.

londons_explore 3y ago
I think this system has to be designed for some users who will never be online. Think of villages where there is no internet access yet (only 8% of Eritrea has access to the internet for example!). Hence there can't be a 'if you don't log in for 7 days you lose your money' mode.
- vinay_ys 3y ago
  Let me clarify: if you have you device with you (didn't lose the device) and you didn't make contact with another online device for more than cool-off period, your device tokens won't be refreshed and they will expire and become unspendable. You don't lose that money – it is still in your account and will be available for you spend as soon as you go online. The "lose your money" scenario is only if you lose your device and someone finds your device and spends the money on the device within the cool-off period. It is equivalent to losing your cash wallet and someone else spending your cash. Except in case of cash, that stolen/found cash is lost forever and is valid to be spent by the thief/finder forever whereas in this case there is a small time-window after which you automatically don't actually lose your money!

londons_explore 3y ago

I think this system has to be designed for some users who will never be online. Think of villages where there is no internet access yet (only 8% of Eritrea has access to the internet for example!). Hence there can't be a 'if you don't log in for 7 days you lose your money' mode.

vinay_ys 3y ago
Let me clarify: if you have you device with you (didn't lose the device) and you didn't make contact with another online device for more than cool-off period, your device tokens won't be refreshed and they will expire and become unspendable. You don't lose that money – it is still in your account and will be available for you spend as soon as you go online. The "lose your money" scenario is only if you lose your device and someone finds your device and spends the money on the device within the cool-off period. It is equivalent to losing your cash wallet and someone else spending your cash. Except in case of cash, that stolen/found cash is lost forever and is valid to be spent by the thief/finder forever whereas in this case there is a small time-window after which you automatically don't actually lose your money!