Security researchers have discovered a new method to decrypt satellite phone communications encrypted with the GMR-2 cipher in “real time” — that too in mere fractions of a second in some cases.
The new attack method has been discovered by two Chinese security researchers and is based on previous research by German academicians in 2012, showing that the phone’s encryption can be cracked so quickly that attackers can listen in on calls in real time.
Unlike previous 2012 research by German researchers who tried to recover the encryption key with the help of ‘plaintext’ attacks, the Chinese researchers attempted to “reverse the encryption procedure to deduce the encryption-key from the output keystream directly.”
The attack method requires hitting a 3.3GHz satellite stream thousands of times with an inversion attack, which eventually produces the 64-bit encryption key and makes it easier to hunt for the decryption key, allowing attackers to decrypt communications and listen in to a conversation.