I've found a page from Digicert that made me very confusing.
https://www.digicert.com/compare-and-buy-ssl-certificates/
In the "Technical Specifications" Section, it listed "Symmetric 256-bit encryption"
In my opinion, the SSL certificate is only used to verify the identity of the server. The encryption strength is related to the configuration of the server.
For example, I would list a few CipherSuites:
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS_DHE_RSA_WITH_AES_128_CBC_SHA
TLS_RSA_WITH_3DES_EDE_CBC_SHA
The SSL certificate should only determin whether the bolded text is "RSA" or "ECDSA". And the other KeyExchange and Encryption method should be determined during the SSL handshake.
The real Symmetric encryption methods' names are what after "_WITH_"
Then my question is how can a SSL certificate determin the symmetric encryption strength? Shouldn't it be determined by the configuration od the server?
Sorry for my poor English ....
----------------Edited 2018.07.27 09:01 UTC----------------
I've found a reseller of Symantec that sell two kinds of SSL certificates, and the only differences between these two are encryption length and price.
The link is here: https://www.trustauth.cn/symantec-ssl
(You may use your browser's translate plugin tp translate this site)
And here's a screenshot of the translated page:
I've ask their Pre sale consultation staff what are the differences between these two. They said that The certificate can determine the encryption strength!
Then... anyone knows whether Symantec(Digicert) sell two kinds of EV and OV certificates and distinguish them by EVPro,EV and OVPro,OV ?
I don't think there is any difference between these two kinds of certificates...