I have always thought that the currency system of the game is kind of messy. Here is the proposal:

1. Weapon modification (add slot, retrieve mods etc) to cost scrip instead, after probably adjusting the cost. Scrip is about 1/3 as plentiful as ark salvage so we can lower the cost to 1/3. The effect is that scrip gets an actual meaningful use.

2. Remove all key codes rewards. Instead the rewards are given in Ark salvage. So you get 5000 ark salvage during Arkfalls for example. This is tie to part 3.

3. You purchase lock boxes with ark salvage directly, ie 64K ark salvage for a T4. Not more buying keys.

This proposal solves a few issues with current system.

1. Reduce redundant action of buying keys to buy lock boxes.
2. Give scrip a more useful purpose.
3. Makes it possibly to increase ark salvage rewards in emergencies/missions to provide the effect of key fragments where the effort might not deserve to earn a whole key.
4. And most important of all, no more silly 75 key code cap!!!