http://protonmailrmez3lotccipshtkleegetolb73fuirgj7r4o4vfu7ozyd.onion/blog/best-encryption-for-emails
(new window) TLS Transport Layer Security (TLS) is a cryptographic protocol used to secure web communications across a network. Due to the versatility of TLS, it is used widely in various technologies, such as the opening of websites or web apps, instant messaging, and email.