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Decrypt a Key File to Disarm IED

Thanks to your hard work we were able to eventually geolocate the device and work with military partners to retrieve the system for further analysis. It turned out to be a test system that one of the IED developers had been using in lieu of a live device. We provided the system to a team of software reverse engineers and their preliminary assessment is that we have a fully functional copy of the IED software (client and server), a key file (952606818.key.enc), and a dummy driver that emulates the various IED states ( Analysts believe that this key file contains the information needed to authenticate to a real IED (somewhere in the field) and send commands to it. Presumably this test system was used to validate the software and key file before it was deployed to an actual IED. Since the key file appears to be encrypted, we are going to need your help to figure out a way to decrypt it. This should enable us to disarm the fielded IED that uses this key, though we will still need to figure out exactly how it is being used for authentication (next task). The goal of this task is for you to obtain the decrypted contents of the key file.

captured client file: client
captured server file: server
captured library: captured key file: 952606818.key.enc

source: Codebreaker Challenge, 2016

solution: solution

Paul Erdos
Ladies on Campus
Oscar Robinson