You can have many different levels of security with PGP. For lots of people, keeping your master key on your computer is good enough, and it's better than no PGP at all. But this guide is my max-security PGP setup. Here are the threats and mitigations that I'm concerned with:
- Quantum cracking: It's likely that someday people will be able to crack RSA and DSA keys using quantum computers. ECC keys are likely also crackable, but can be faster, shorter, and possibly more secure. There's some controversy about which type of ECC keys to use; I settled on Curve 25519.
- Key reuse: It's a bad idea to reuse your encryption key for signing. (It's safe with current algorithms, but it