NSA may be transcribing your phone calls, Snowden documents reveal

The National Security Agency logo is shown on a computer screen inside the Threat Operations Center at the NSA in Fort Meade, Maryland.Reuters

The National Security Agency (NSA) may not just be listening to your phone calls. It may also be keeping transcripts of your private phone conversations.

Top-secret documents from the archive of Edward Snowden, NSA's controversial former contractor, revealed that the spy agency has the capability to automatically recognize the contents within phone calls.

The NSA's capabilities to access your private conversations, however, do not stop there. Snowden documents also indicated that the NSA uses automated speech recognition technology to search, index and transcribe voice communications.

The confidential documents showed that analysts from the NSA celebrated nearly a decade ago the development of what they called as the "Google for Voice," which creates rough transcripts and phonetic representations that can easily be searched and stored.

The Snowden documents also described in detail how the NSA extensively used keyword searching and computer programs for the analysis and extraction of phone conversations.

According to the ex-NSA contractor files, this speech recognition and transcription tool was used in war zones like Afghanistan, Iraq and Latin America.

It remains unclear, however, to what extent the intelligence agency uses its capability to turn speech into text.

Asked once during a Capitol Hill event about how the spy agency exactly carries out its speech-to-text capability, Robert Litt, general counsel for the Office of the Director of National Intelligence was elusive.

Litt simply said that the NSA has "all sorts of technical capabilities," which he maintains are being used in accordance with US laws.