Alas, because of the way it works, a true HTTPS Everywhere extension for Safari is presently impossible to implement in a way that provides maximum security. Nonetheless, the SSL Everywhere extensionbrings something very similar to Apple's browser. The only difference is that the initial data transmission when you access a site isn't encrypted, which can provide interested hackers or snoops with a little more information than is ideal. However, once you've been switched over to secure HTTP - which essentially happens immediately from the user's perspective - then everything is, of course, encrypted.
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