All Firefox versions support AES 256 bit encryption, so the strength shouldn't be a problem. Firefox 14 won't support TLS 1.2 and TLS 1.1 (only TLS 1.0). You should update to Firefox 16.0.2 as that is the latest version for Mac Ox 10.5 Test your browser: *https://www.ssllabs.com/ssltest/viewMyClient.html ----- You can consider to update to OS X 10.6 to be able to use current Firefox releases. Last Firefox for Mac Intel OS X 10.5: *http://download.cdn.mozilla.net/pub/firefox/releases/16.0.2/mac/