GSM Cellular Crypto Code Breaking

Most people think that “hackers” are just a bunch of criminals. But those of us who are real hackers know better. We know that to be a true hacker, you must dare to discover new things, and have the moral strength to turn your knowledge to good.

In this brief Guide we give an example of how real hackers are working to reveal to the world how to crack open the technique that is supposed to provide privacy to GSM (Global System for Mobile communications) cell phone calls.

Why would anyone want to ruin the privacy of GSM cell phone calls? The problem is that this privacy has already been ruined by those who already know how to crack this code, for example spy agencies. Who knows, perhaps crime organizations also are able to snoop on GSM phone calls. This is a big deal because over three million people are using GSM phone and they don't realize they could be snooped upon.

Enter hackers – specifically, a group led by a member of one of the oldest hacker groups around, Germany's Chaos Computer Club. Karsten Nohl, now chief research scientist with H4RDW4RE, a Sunnyvale, Calif.-based security research firm.

Nohl's solution to this problem was to mount “what could be the most ambitious attempt yet to compromise the GSM phone system.... Others have cracked the A5/1 encryption technology used in GSM before, but their results have remained secret. However, Nohl, who earned a Ph.D. in computer science at the University of Virginia and is a member of Germany's Chaos Computer Club (CCC), intends to go one big step further: By the end of the year, he plans to make the keys available to everyone on the Internet.”

Karsten Nohl discusses Hacking A5 GSM Encryption.  View video here.  Download slides here.

See Nohl's article, Reverse-Engineering a Cryptographic RFID Tag