Author Archives: Luke Norris

The U.S. National Security Agency (NSA) has the technical capacity to crack the most commonly-used cellphone encryption technology, and in doing so it can decode and access the content of calls and text messages, according to a Washington Post report published Friday.

Citing a top-secret document leaked by former intelligence contractor Edward Snowden, the report states that the agency can easily break a technology called A5/1, the world’s most common stream cipher used to encrypt cellular data as it transmits to cell towers.

Privacy and security researcher Ashkan Soltani, co-author the Post‘s report, explains that encryption experts have long been aware of the weakness of A5/1. The technology makes use of decades-old 2G GSM (Global System for Mobile Communications) cellular network technology.

The so-called “summer of revelations” on NSA surveillance tactics, fueled by Snowden’s leaked documents, has brought to light the agency’s vast data-collecting capabilities. The NSA’s considerable abilities to collect and decode cellular data would seem to allow it to track private conversations on a very wide scale.

Of course, it would be against the law for the NSA to use these capabilities to spy on Americans without a court order. But experts believe other nations have probably developed many of these same surveillance technologies.

Here’s how the NSA responded to the Post‘s inquiry about the topic:

Throughout history nations have used encryption to protect their secrets, and today terrorists, cyber criminals, human traffickers and others also use technology to hide their activities. The Intelligence Community tries to counter that in order to understand the intent of foreign adversaries and prevent them from bringing harm to Americans and allies.

NSA phone spying got the NSA in a bit of diplomatic hot water in October, when reports surfaced that the agency may have spied on German Chancellor Angela Merkel’s conversations.

Global cell service providers have been slow to update their networks because it would be an “expensive, time-consuming undertaking that likely would cause interruptions in service for some customers,” according to the Post, though this is less true in the U.S. and “the wealthiest nations.”

The top-secret document does not indicate whether or not the NSA can infiltrate newer 3G and 4G GSM networks, nor does it say if the agency can break another cellular encryption technology called Code Division Multiple Access, or CDMA, which Verizon, Sprint and some foreign companies use, according to the Post.

AT&T, the largest GSM provider in the U.S., is in the process of upgrading its networks to what’s called A5/3 encryption, the Post reports, which requires 100,000 times more computing power to break compared to A5/1. T-Mobile told the Post that it is “continuously implementing advanced security technologies in accordance with worldwide recognized and trusted standards,” but the company did not go into specifics.

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