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- The US National Security Agency has designed and patented a new technology that could aid it in spyingon international telephone calls. The NSA patent, granted on 10 August,is for a system of automatic topic spotting and labelling of data. Thepatent officially confirms for the first time that the NSA has beenworking on ways of automatically analysing human speech.
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- The NSA's inventionis intended automatically to sift through human speech transcripts inany language. The patent document specifically mentions"machine-transcribed speech" as a potential source.
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- Bruce Schneier,author of Applied Cryptography, a textbook on the science of keepinginformation secret, believes the NSA currently has the ability to usecomputers to transcribe voice conversations.
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- "One of the holy grails ofthe NSA is the ability automatically to search through voice traffic.They would have expended considerable effort on this capability, andthis indicates it has been fruitful," he said.
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- To date, it has beenwidely believed that while the NSA has the capability to conduct fullyautomated, mass electronic eavesdropping on e-mail, faxes and otherwritten communications, it cannot do so on telephone calls.
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- While cautioning thatit was difficult to tell how well the ideas in the patent worked inpractice, Schneier said the technology could have far-reaching effectson the privacy of international phone calls.
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- "If it works well, thetechnology makes it possible for the NSA to harvest millions oftelephone calls, looking for certain types of conversations," hesaid.
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- "It's easy to eavesdrop on any single phone call, butsifting through millions of phone calls looking for a particularconversation is difficult," Schneier explained. "In terms ofautomatic surveillance, text is easier to search than speech. Thispatent brings the surveillance of speech closer to that oftext."
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- The NSA declined to comment on the patent. As a general policy,the agency never comments on its intelligence activities.
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- Yaman Akdeniz,director of Cyber-Rights & Cyber-Liberties UK, warned that withthe new patentand a proposed AT&T and BT joint venture, which willallow US law enforcement agencies to tap the new communicationsnetwork: "We might have a picture in which all British communicationsare monitored by the NSA."
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- The revelation of the NSA's patent is likely to causetensions with the European Parliament. Over the past two years, theParliament has commissioned several reports which examined whether theNSA has been using its electronic ears for commercial espionage,particularly in areas where US corporations compete with European andother companies.
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- The NSA relies on an international web of eavesdroppingstations around the world, commonly known as Echelon, to listen intoprivate international communications. The network emerged from a secretagreement signed after the Second World War between five nationsincluding Australia, New Zealand, Canada, Britain and the US. Two ofthe NSA's most important satellite listening stations are located inEurope, at Menwith Hill in Yorkshire and Bad Aibling inGermany.
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- Julian Assange, a cryptographer who moderates the onlineAustralian discussion forum AUCRYPTO, found the new patent whileinvestigating NSA capabilities.
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- "This patent should worrypeople. Everyone's overseas phone calls are or may soon be tapped,transcribed and archived in the bowels of an unaccountable foreign spyagency," he said.
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- One of the major barriers to using computersautomatically to sift through voice communications on a large scale hasbeen the inability of machines to "think" like humans whenanalysing the often imperfect computer transcriptions of voiceconversations.
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- Commercial software that enables computers to transcribe spokenwords into typed text is already on the market, but it usually requiresthe machine to spend time learning how to understand an individual voicein order to produce relatively error-free text. This makes such softwareimpractical for a spy agency which might want automatically to transcribeand analyse telephone calls on a large scale.
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- It is also difficult forcomputers to analyse voice conversations because human speech oftencovers topics that are never actually spoken by name. According to theNSA patent application, "much of the information conveyed inspeech is never actually spoken and... utterances are frequently lesscoherent than written language".
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- US Patent number 5,937,422reveals that the NSA has designed technology to overcome these barriersin two key ways. First, the patent includes an optional pre-processingstep which cleans up text, much of which the agency appears to expectto draw from human conversations. The NSA's "pre-processing"will remove what it calls "stutter phrases" associated withspeech based on text.
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- Second, the patent uses a method by which a computerautomatically assigns a label, or topic description, to raw data. If themethod works well, this system could be far more powerful than traditionalkeyword searching used on many Internet search engines because it couldpull up documents based on their meaning, not just their keywords.
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- Dr Brian Gladman,former MoD director of Strategic Electronic Communications, said thatwhile he doubted the NSA had deployed the patented system yet, the newtechnology could become a "potent future threat" toprivacy.
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- "If the technology does what it says - automaticallyfinding and extracting the meaning in messages with reasonable accuracy- then it is way ahead of what is being done now," he said.
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- The best way forpeople to protect their private communications was to use encryption,he said. Encryption software programs scramble data to preventeavesdropping. "I'm afraid widespread interception is a fact oflife and this is what makes encryption so important," he said.
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- "The problem inthe UK is that our government is working with the US to prevent UKcitizens defending themselves using encryption," he said,referring to the continuing use of export controls to hamper thewidespread availability of encryption products.
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- The NSA's current spytechnology may be more advanced than methods described in the patentbecause the application is more than two years old. The US PatentOffice approved the patent on 10 August this year, but the NSAoriginally lodged the application on 15 April 1997. The US Patentoffice keeps all applications secret until it issues a patent.
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