New Attack Can Now Decrypt Satellite Phone Calls in 'Real Time'

Chinese researchers have discovered a way to rapidly decrypt satellite phone communications -- within a fraction of a second in some cases. From a report on ZDNet: The paper, published this week, expands on previous research by German academics in 2012 by rapidly speeding up the attack and showing that the encryption used in popular Inmarsat satellite phones can be cracked in "real time." Satellite phones are used by those in desolate environments, including high altitudes and at sea, where traditional cell service isn't available. Modern satellite phones encrypt voice traffic to prevent eavesdropping. It's that modern GMR-2 algorithm that was the focus of the research, given that it's used in most satellite phones today. The researchers tried "to reverse the encryption procedure to deduce the encryption-key from the output keystream directly," rather than using the German researchers' method of recovering an encryption key using a known-plaintext attack. Using their proposed inversion attack thousands of time on a 3.3GHz satellite stream, the researchers were able to reduce the search space for the 64-bit encryption key, effectively making the decryption key easier to find. The end result was that encrypted data could be cracked in a fraction of a second.