Standard email is sent in plain-text across the internet. This means network nodes, ISPs, and mail gateways can read your message body. To protect highly sensitive communications, you must use email encryption. PGP and S/MIME are the two industry-standard protocols for securing mail payloads.
1. PGP (Pretty Good Privacy)
PGP is a decentralized public-key cryptography system. You generate a public key and a private key. Senders encrypt emails using your public key, and you decrypt them using your private key. PGP is highly flexible and popular among privacy advocates, but requires manual key management.
2. S/MIME (Secure/Multipurpose Internet Mail Extensions)
S/MIME is a centralized encryption system integrated into many corporate email clients. It relies on digital certificates issued by a trusted Certificate Authority. Recipient clients verify your identity certificate automatically. S/MIME is easier to use in enterprise environments, but requires paying for trusted certificates.
Both PGP and S/MIME ensure that your email bodies are completely unreadable by third parties, guaranteeing absolute privacy and message integrity across the internet.