Today's Tech: NSA listening in on world leaders' phone calls, BBM fake review scandal, and London startups being stifled by rent

Dutch authentication technology firm Primary-Net has unveiled its plans for a fingerprint-based payment system which it claims could replace PIN numbers and credit cards in payment transactions. The Primary Pass, its new authentication device, was unveiled at an event at the Science Museum in London. "We are revealing something like the magnitude of a total cure for cancer...for the internet," the company claimed, slightly hyperbolically. The Primary Pass, the device on which the company's whole system rests, is a fingerprint scanner the size and shape of a portable mouse. It remains secure by having no other software or operating system installed, making it virtually impossible for malware to be introduced.

London Tech City businesses are being stifled by oppressive rent prices, reports have shown. Soaring operational costs, an ongoing struggle to recruit qualified staff and a restrictive property squeeze are all contributing to put the pressure on small tech start-ups. The most commonly cited barriers to growth included the actual cost of running the business, a too-shallow pool of qualified and available staff, and a squeeze on office space that's not only affordable, but high quality. The price of rent Shoreditch's Tech City, the survey also found, has rocketed in the past year by 46 per cent.

Following the launch of BBM for Android and iOS on 21 October, Blackberry has been accused of 'astroturfing', a process where a company artificially inflates its reputation through fake reviews online. "Thank you so much Blackberry team," one review read. "I was waiting this app. It is really great user friendly and smooth." This same text was copied repeatedly, seemingly by different users, over and over on Google Play. BlackBerry has denied all involvement, claiming that the beleaguered Canadian-based phone maker has "no knowledge of how reviews were created or populated."

The American National Security Agency (NSA) monitored the phone conversations of 35 heads of state, according to yet another leaked memo provided by whistleblower Edward Snowden. The conversations were allegedly intercepted after another US government department handed the leaders' mobile and home phone numbers to the NSA. The memo was a general call to members of other departments to share their 'rolodexes', or address books, with the agency. "In one case," the memo states, "a US official provided NSA with 200 phone numbers to 35 world leaders", including "43 previously unknown numbers." However, the memo concedes, little "reportable intelligence" was actually gathered from these numbers. The leaders' identities are as of yet unknown.