SMTP TLS: All About Secure Email Delivery over TLS
Monday, October 2nd, 2017TLS stands for “Transport Layer Security” and is the successor of “SSL” (Secure Socket Layer). TLS is one of the standard ways that computers on the internet transmit information over an encrypted channel. In general, when one computer connects to another computer and uses TLS, the following happens:
- Computer A connects to Computer B (no security)
- Computer B says “Hello” (no security)
- Computer A says, “Let’s talk securely over TLS” (no security)
- Computer A and B agree on how to do this (secure)
- The rest of the conversation is encrypted (secure)
In particular:
- The meat of the conversation is encrypted
- Computer A can verify the identity of Computer B (by examining its SSL certificate, which is required for this dialog)
- The conversation cannot be eavesdropped upon (without Computer A knowing)
- A third party cannot modify the conversation
- Third parties cannot inject other information into the conversation.
TLS and SSL are used for many different reasons on the internet and help make the internet a more secure place. One of the popular uses of TLS is SMTP for securely transmitting email messages between servers. See also:
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