I am looking into buying a SSL certificate for my website.
I have found a certificate available from RapidSSL.
- Will this certificate prevent a MITM attack?
- Will this certificate show warnings to the user (because it isn’t an EV certificate)?
SSL certificates don't necessarily prevent man-in-the-middle attacks, however it does make it significantly more difficult to do so silently. SSL which is implemented incorrectly or insufficiently (i.e.: pages that load insecure resources) still has viable open vectors of attack.
SSL itself is designed to help ensure the secure transfer of data over a public network. SSL uses asymmetric cryptography utilizing public and private keys. Certificate authorities seek to expand on this technical endeavor of security by establishing a recognizable chain of trust. Extended validation (EV) certificates don't make the process much more secure technically, but rather serve to represent a closer scrutinization of the trusted party's identity. As such, even non-EV certificates will still appear as trusted as long as the issuing CA is recognized as trusted by the client browser.