Two research papers show potential weaknesses in the encryption sued to secure the devices.
Naked Security explains:
Is the encryption used to secure satellite phone communications from eavesdropping secure or isn’t it?
Until 2012, the answer would have been a reasonably confident “yes”, but two theoretical papers, a German study of that year (added to in 2013), and a Chinese follow up published last week have injected growing doubt.
What the researchers have been aiming at is to find weaknesses in the proprietary GMR-1 (Geo-Mobile Radio-1) and GMR-2 stream ciphers, the first running on the Thuraya satellite system, the second used by Inmarsat.