Or if you encrypt your hard drive. Having GPG most certainly doesn't ensure your security though. Hell, not using GPG doesn't even ensure that you will be compromised. If you don't use GPG to send your address over SR then your security is dependent on the server never being seized while it is in a vulnerable state (ie: booted on), everybody who has legitimate access to the server being honest and non-malicious, and the server never being penetrated by malicious hackers. Now, the server is almost always on so if it is seized then you are pretty fucked. Tor is better than nothing anonymity for servers, but everybody knows that hidden services are not the most anonymous things in the world. Not to mention there is always the risk that the server will leak its IP address etc. We are pretty positive at this point that DPR is legitimate currently, and we hope that the people he picked to have access to the server are legitimate, but people can of course turn to the enemy if they are compromised, and it is not unheard of for undercovers to infiltrate criminal groups at a high level (ie: master splynter gained legitimate administrative access to a carder forum). As far as hackability goes, well at least 99.9999999% of software is hackable, and the software running SR is no different. On the other hand, if you use GPG then your security is dependent on extremely large composite numbers being difficult to factor into primes, and essentially all mathematicians believe that extremely large composite numbers are extremely difficult to factor into primes. So it is up to you if you want your security to rely on the anonymity of Tor hidden services (which is undoubtedly less than the anonymity of regular Tor clients), the security of the server (which is undoubtedly not perfectly secure), and the benevolence of the people with administrative access to the server (which is indeterminable), or if you want your security to rely on something that mathematicians hold to be fact (ie: that it is very hard to factor a very large composite number into primes).