After finishing the Gaining Influence job, talk to Lassard to start this one. Head out to the Wasteland and follow your mini-map to Jackal Territory and into Jackal Canyon. Go until you come to a bridge, at the end of it there is a switch that opens a gate that you passed earlier. Continue on until you come to what seems like a dead end, and there is a zipline to take. You'll then come to an elevator you can take down. Keep pushing on until you get to a circular area with balloons. The balloons are explosive so be careful and use them to your advantage. When you get to the bottom of this area, you'll find the ark. The ark equipment is in the wall that you have to open. Picking it up will give you the Decrypted achievement. There will be a zipline machine at the top of the stairs to you left to take you out. Head back to Lassard to finish the job. Talk to Portman to start the Assault the Authority Bridge job.
Collector Card: Jackal Crossbow - As soon as you enter Jackal Canyon, its up to the left on a box.
Collector Card: Jackal Club - After you cross the bridge, it's on the table to the left before you pull the switch.