Feeds

Mobile operators pooh-pooh universal phone-snooping plan

'What, us worry?'

The Power of One eBook: Top reasons to choose HP BladeSystem

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." ®

Designing a Defense for Mobile Applications

More from The Register

next story
Mozilla fixes CRITICAL security holes in Firefox, urges v31 upgrade
Misc memory hazards 'could be exploited' - and guess what, one's a Javascript vuln
How long is too long to wait for a security fix?
Synology finally patches OpenSSL bugs in Trevor's NAS
Don't look, Snowden: Security biz chases Tails with zero-day flaws alert
Exodus vows not to sell secrets of whistleblower's favorite OS
Roll out the welcome mat to hackers and crackers
Security chap pens guide to bug bounty programs that won't fail like Yahoo!'s
HIDDEN packet sniffer spy tech in MILLIONS of iPhones, iPads – expert
Don't panic though – Apple's backdoor is not wide open to all, guru tells us
Researcher sat on critical IE bugs for THREE YEARS
VUPEN waited for Pwn2Own cash while IE's sandbox leaked
Four fake Google haxbots hit YOUR WEBSITE every day
Goog the perfect ruse to slip into SEO orfice
prev story

Whitepapers

Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Seven Steps to Software Security
Seven practical steps you can begin to take today to secure your applications and prevent the damages a successful cyber-attack can cause.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.