Feeds

Mobile operators pooh-pooh universal phone-snooping plan

'What, us worry?'

Internet Security Threat Report 2014

Mobile operators have struck back at organizers of an open-source project that plans to crack the encryption used to protect cell phone calls, saying they are a long way from devising a practical attack.

"The theoretical compromise presented at the Black Hat conference requires the construction of a large look-up table of approximately 2 Terabytes - this is equivalent to the amount of data contained in a 20 kilometre high pile of books," the group, which represents almost 800 operators in 219 countries, said in a statement issued Friday. "In theory, someone with access to the data in such a table could use it to analyse an encrypted call and recover the encryption key."

The GSMA went on to say that even if such a table were built, the researchers still would need to build a complex radio receiver to process the raw radio data.

The vast majority of world's cell phone calls are protected by an algorithm known as A5/1 that has been in existence for more than a decade, said project leader Karsten Nohl, a cryptography expert and a researcher at the University of Virginia. Because it hails from the cold-war era when export laws prohibited the exportation of strong cryptography, the cipher is relatively trivial to break using a large number of networked computers.

More recently, cell phone makers have folded a newer cipher known as A5/3 into handsets to protect internet communications. Because its key is twice as long as A5/1, it's about a quintillion times harder to break, Nohl estimates. But despite the uncontested superiority of the newer algorithm, handset manufacturers still cling to the older one to protect voice calls.

"This is cold war stuff," Nohl told The Register in explaining why he spearheaded the project, which plans to use a distributed, peer-to-peer computing system to create the table needed to crack A5/1. "I don't see why I should be using something that was intentionally weakened during the cold war."

Indeed, in many respects, the GSMA's statement reads like a relic from the 1960s, when it was still fashionable to believe that arcane and proprietary technologies were sufficient to thwart determined hackers from breaking into protected systems.

"The complex knowledge required to develop such [signal-processing] software is subject to intellectual property rights, making it difficult to turn into a commercial product," it states.

The statement said the GSMA is phasing in A5/3, but provided no timetable or other details.

The GSM rainbow table project was announced at the recent Black Hat security conference in Las Vegas.

Nohl has already proved to be adept at defeating such security-through-obscurity defenses. In late 2007, he unveiled a practical attack on the world's most popular smartcard. For decades, Netherlands-based NXP Semiconductors relied on a proprietary algorithm to protect its widely used Mifare Classic wireless card.

"I'm puzzled by the GSMA's attempt to hide behind the alleged inability of hackers to snoop GSM traffic," Nohl wrote in an email to reporters. "This is 20 years old technology that ships in billions of handsets. The GSMA should take the hacker community and its current interest in GSM technology more serious." ®

Internet Security Threat Report 2014

More from The Register

next story
George Clooney, WikiLeaks' lawyer wife hand out burner phones to wedding guests
Day 4: 'News'-papers STILL rammed with Clooney nuptials
Shellshock: 'Larger scale attack' on its way, warn securo-bods
Not just web servers under threat - though TENS of THOUSANDS have been hit
Apple's new iPhone 6 vulnerable to last year's TouchID fingerprint hack
But unsophisticated thieves need not attempt this trick
PEAK IPV4? Global IPv6 traffic is growing, DDoS dying, says Akamai
First time the cache network has seen drop in use of 32-bit-wide IP addresses
Oracle SHELLSHOCKER - data titan lists unpatchables
Database kingpin lists 32 products that can't be patched (yet) as GNU fixes second vuln
Who.is does the Harlem Shake
Blame it on LOLing XSS terroristas
Researchers tell black hats: 'YOU'RE SOOO PREDICTABLE'
Want to register that domain? We're way ahead of you.
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Storage capacity and performance optimization at Mizuno USA
Mizuno USA turn to Tegile storage technology to solve both their SAN and backup issues.
The next step in data security
With recent increased privacy concerns and computers becoming more powerful, the chance of hackers being able to crack smaller-sized RSA keys increases.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
A strategic approach to identity relationship management
ForgeRock commissioned Forrester to evaluate companies’ IAM practices and requirements when it comes to customer-facing scenarios versus employee-facing ones.