When surfing the web without using SSL, any data you submit and any page you view, could potentially be monitored by others. For example if you are viewing this page from your work PC, possibly your employer could see this in the log files of your company firewall. If you use SSL, the data sent between your PC and the website is encrypted, so that an intermediary cannot see the exact data, that is being sent via the internet connection. In general, if a website is available via HTTPS (HTTP via SSL), you should prefer to use this instead of plain HTTP. It might be slightly slower, but with normal PCs and normal network connections, you probably will not even notice the difference.
When you decide to use SSL to view the IARC website, you will most likely get a message from your browser, saying that the SSL certificate cannot be properly verified. This is because we are not using a commercial certificate from an accepted certificate authority, as such a certificate costs several hundred Euros per year. We are using a so called "self-signed certificate", which means that we have created the certificate ourselfs and no one has verified it. This means that this way of using SSL is still prone to a possible "man in the middle attack". If you want to be really sure you are talking to the correct website you can send us a PGP encrypted mail via the PGP key listed on our contact page and we will send you the fingerprint of the certificate which we are using, so that you can verify it and then trust it.
Since we have several SSL connections via HTTP running on the same machine with different certificates, we also need different ports for these connnections and the default port 443 was already used by another certificate. In some rare cases you might be behind a firewall which will not allow you to connect to port 10443, which we are using. In this case we are sorry, but you will then not be able to view our website via SSL.