The NSA reportedly has its own version of a Sky TV or TIVO recorder, but for entire foreign country telephony networks.
According to the latest leaked documents from former NSA contractor Edward Snowden, not only does the US spy agency have a 30 day buffer on its whole-country telephony recording capability, but it has had the technology since 2009.
The Washington Post - which seems to have a direct line to Snowden since he first started releasing information last May – reports that the MYSTIC surveillance system is capable of storing "100 percent" of a foreign country's phone calls.
The fact that the system has been in place since 2009 means that the technology almost certainly pre-dates the migration to an IP backbone that most national telcos have moved to in recent years. Here in the UK, for example, BT's 21CN IP migration plan was only 50 per cent completed by the start of 2009, SCMagazineUK.com notes.
This suggests that the calls are being transcribed from an analogue into a highly compressed digital format. Even so, the volume of data storage involved is breathtaking. The UK, for example, generated 254 billion minutes of calls in 2010 (according to the last complete set of figures available from Ofcom), of which almost 50 per cent were mobile originated or terminated.
Interestingly, The Washington Post cites an NSA senior manager referring to MYSTIC as a time machine - "one that can replay the voices from any call without requiring that a person be identified in advance for surveillance."
The paper has cross-referenced Snowden's claims with various reports/citations from the US Government and concluded that the MYSTIC platform does exist, even if its capabilities are still theoretical.
The most interesting take-out from Snowden's assertions is that analysts listen to only a fraction of a per cent of the calls, although the absolute numbers are high, centering on millions of voice clippings for processing and long-term storage.
Digital forensics specialist Professor Peter Sommer - who is also a Visiting Professor at Leicester's de Montfort University - told SCMagazineUK.com that back in 2003 the US Congress killed off a pet project of John Poindexter (then the US Deputy National Security Adviser) called ‘Total Information Awareness'.
"The claim had been that if you collect enough material you get enough advance warning to make America safe," he said, adding that the notion was always flawed, among other reasons, because you need to know what you are looking for in the form of danger signatures.
Professor Sommer went on to say that, without the danger signatures, all you are doing is spending a great deal of money and getting large numbers of false positives.
Against this backdrop, he says, MYSTIC has the same problems and the likelihood of discovering `new or emerging threats' by this means - as opposed to more conventional intelligence analysis - seems remote.
"EU Data Retention policies, which are limited to communications data not content, are adequate to deal with the aftermath of an unexpected event, so looking back into history may be useful to identify a perpetrator and the nature of the problem," he concluded.