If you want detailed descriptions of non-government special SAS ops by an individual in Finland and Estonia, where it is extremely frigid, dirty, dark, the government has failed (Estonia), the landscape and buildings represent a 1940-70's crumbling infrastructure that is dirty, dimly lit, under-heated, overpolluted, with mafia operatives operating at will independently (Estonia), then this is the book for you. If you're looking for gritty personal operations details involving that scenario and survival during and after an operation, then you'll find it here. 5 stars if that's what you're looking for.
There is no discussion of technology. If I mention Firewall 3 times, then I've exceeded it's use and explanation in the book. This is simply an operations book of detailed miserable minutia, that drags on for 200 pages past it's first climax, where the book should have ended. The name of the book and description describing encryption was just a charade to sell it.
Hats off to people with the personal stamina and trained skills to accomplish this level of infiltration and precise destruction. But that wasn't what I thought the book would rest solely on.
If you're looking for a techno-thriller with some James Bondish action to provide a plot, then keep on looking.