The US' National Security Agency (NSA) reportedly cracked the encrypted data on smartphones to access information for its secret surveillance programmes.
According to the documents leaked by whistleblower Edward Snowden, the NSA boasted internally of being able to crack encryption codes of smartphones by leading manufacturers like Apple, Blackberry and phones that work on Google's Android OS.
The NSA had set up working parties to ensure that each of the main operating systems had a 'back door' accessible to spies for data including users' contact lists, text messages logs and information on geographical locations, news.com.au reports.
The report said that the agency is able to penetrate iPhone data via the owner's personal computer after their data had been synchronised.
For the safety of user data on the web or on smart devices, encryption technology is used in which the data is transformed into codes, making it difficult to intercept. However, critics warn that hackers may one day discover the NSA's 'back doors' and exploit them for crime, the report added.