Secure Computing

Secure Web & Email: SSL & TLS

Secure Sockets Layer (SSL) is a security protocol used to transmit private communications via the Internet. Many Web sites use the SSL protocol to protect confidential user information, such as credit card numbers. By convention, URLs that require an SSL connection start with "https" instead of "http." Many email clients also support SSL as a means to encrypt messages to keep them safe from identity thieves who watch public wireless networks looking for passwords and credit card numbers. An updated version of the SSL protocol is called Transport Layer Security (TLS), but SSL and TLS are essentially the same standard.

SSL and TLS provide three security measures:

  • Client authentication: Ensures that the client can uniquely identify the server, and can verify that data transfer will be secure.
  • Data encryption: The data is scrambled using complex encryption algorithms, so that even if it is intercepted en route it cannot be deciphered.
  • Data integrity checks: Verifies that there has been no alteration of the data during transit.

Supported email software

You can enable SSL with most, but not all, of the IMAP and POP ITS supported email clients. Look at the pared-down settings for using authenticated email or contact the Help Desk at 203-432-9000.

Comparison with encryption for email privacy

SSL encrypts messages/attachments, but only in transport between SSL/TLS enabled mail servers. So, your SSL email will be secure between your laptop or smartphone and Yale's email servers, but if the message then travels outside the Yale environment to unsecured (non-SSL) email systems (like a Gmail address, for instance), your message is no longer secure and is not protected by SSL.

Diagram on SSL email encryption.

PGP (Pretty Good Privacy) encrypts messages and attachments before they're sent, and the PGP-protected messages are secure anywhere in transit. PGP-protected messages must be unencrypted by the recipient of the message, using a password. This method is much more secure, but at some cost in time and convenience. Software to support PGP encryption is available from the ITS Software Library.

Diagram on PGP email encryption.