Microsoft Windows Security - Don't Save Encrypted Web Pages to Disk
When you exchange information with a secure (SSL-encrypted) web site, such as entering a username and credentials, or typing in your social security number or credit card number, this information may be saved on the local hard disk. If you're using Microsoft Internet Explorer, it's saved in your Temporary Internet Files folder. Even though the information is encrypted, if you share the computer or someone else has physical access, best security practice is not to save this information to disk.
You can configure IE not to save encrypted pages to disk by clicking Tools | Internet Options, clicking the Advanced tab, and scrolling down in the Settings list to check the box labeled "Do not save encrypted pages to disk." This setting is not enabled by default.