팀 동생이 공유해준 링크인데 개념정리에 도움이 많이 됩니다.
http://www.pgpi.org/doc/pgpintro/
그림만 따왔습니다.
Figure 1-2. Conventional encryption
Figure 1-3. Public key encryption
Figure 1-4. How PGP encryption works
Figure 1-5. How PGP decryption works
Figure 1-6. Simple digital signatures
Figure 1-7. Secure digital signatures
Figure 1-8. Anatomy of a PGP certificate
Figure 1-9. A PGP certificate
Figure 1-10. An X.509 certificate
Figure 1-12. Hierarchical trust