In brief: Researchers from universities across Europe recently published a paper in which they speculated that a weakness uncovered in the GEA-1 encryption algorithm wasn’t by chance. Turns out, they were right.
As Vice highlights, GEA-1 was used to encrypt cell phone data primarily in the 1990s and 2000s. The algorithm was originally said to offer full 64-bit security but in their cryptanalysis, the team found that its security was limited to just 40-bit, by design.
In its paper, the team said they obtained the proprietary GEA-1 and GEA-2 algorithms from a source that wished to remain anonymous. This allowed them to conduct a full analysis and discover the weakness, which seemed “ unlikely to occur by chance .”
An attacker with the ability to intercept cell phone data traffic could have exploited the weakness to decrypt all messages in a session.
Vice reached out to the organization that designed GEA-1, the European Telecommunications Standards Institute ( ETSI ). In an e-mailed statement, a spokesperson admitted that the algorithm did contain a weakness, but that it was introduced because it had to be.
“We followed regulations: we followed export control regulations that limited the strength of GEA-1,” the spokesperson said.
The export regulations the spokesperson mentioned were common at the time. According to The Register , France had one such rule in place that banned anything over 40-bit encryption.
“To meet political requirements, millions of users were apparently poorly protected while surfing for years,” said Håvard Raddum, a researcher that worked on the paper.
The issue here, of course, is the fact that the GEA-1 standard made no mention of any export restrictions at the time.
The team additionally found that the GEA-2 algorithm was also susceptible to attack, albeit through a more technical approach. Fortunately, neither standard is widely used as newer algorithms are now preferred. Still, some countries and networks apparently still rely on then as a fallback.
Image credit Konstantin Katuev , gonin