How can I farm most effectively for portal keys in a short timespan [duplicate]

Solution 1:

There is not much you can to, other than deploying Heat Sink and Multi-hack mods.

If time is the limit, the most efficient would be:

• Hack 1 time
• Deploy Very Rare Heat Sink: Will set cool down time to 90 seconds
• Deploy Very Rare Multi-hack: Will give you 16 hacks before burnout
• Hack 16 times

Makes 17 hacks in ~24 minutes.

If you have a buddy, let him deploy the same mods you did. That will give you 22 hacks with a cool down time of 58 seconds, so potentially 22 keys in 22 minutes. For each of you.

If you have more time, obviously you should wait with deploying the Heat Sinks to max out the hacks before resetting.

If you don't want to waste the very rare mods, do not need 22 keys or have more time to wait, use only the rare & commons. Here is a very nice tool to calculate the cool down times and max hacks with any combination of deployed mods.