After the flaw found by Yan zhu, it is sure that wordpress will work in the direction of encryption for cookies.https://twitter.com/nacin/status/469639682012495872

What company would you use for SSL Certificates?

I prefer major certificate authorities. Symantec, Thawte, RapidSSL, GeoTrust, AlphaSSL, Comodo etc are some of the finest CAs in all over the world. from the price view you can find pocket pleasing price at www.ssl2buy.com