It looks increasingly likely that the NSA has been hacked, as experts scrutinise leaked code

Analysis of the cyber weapons that hackers say they extracted from the top secret National Security Agency has left a key team of outside experts increasingly certain that the files came from the NSA.

The Russia-based Kaspersky Lab, which has been at the forefront into research of NSA techniques, said it found 347 instances of encryption algorithms in the leaked files that have been seen previously only in NSA-linked computer programming.

A successful hack of the NSA — if that’s what happened — would mark a major defeat for one of the crown jewels of the US government’s defence establishment. The NSA’s hacking unit has been credited with sophisticated cyber weapons, including the code that is credited with crippling the Iranian nuclear programme.

A mysterious group calling itself the Shadow Brokers announced over the weekend that it had penetrated the NSA, stolen sophisticated cyber weapons and digital tools, and opened a global auction for the sale of the still-secret most valuable ones.

The group released 300 megabytes of files to the public for free, and cyber security companies and hackers rushed to examine the coding on the files, which included malware that would allow a controller to get past the most secure of firewalls.