What is ssl certificate ? 
https is an encrypted transmission protocol, the sites use https to avoid sensitive information access by third parties. https encryption protocol = SSL / TLS + http protocol, i.e., with a conventional SSL certificate on http protocol data transmission can be encrypted.
SSL certificate is actually CA public key authentication mechanism for users, including signature and expiration date information, user information public, public keys, authority electronic visa authorities. CA (Certification Authority, Certificate Authority) organization, is to undertake a third-party inspection of the legitimacy of public authority, responsible for specifying policies, steps to verify the user's identity, and the SSL certificate is signed to ensure the identity of the certificate holder and ownership of the public key. CA user organization using the public key for each issuing an SSL certificate, the role of SSL certificate is a personal / corporate listed in the certificate to prove the legal owner of the public key listed in the certificate. CA digital signature allows institutions *** can not forge and tampering with a certificate.
Why websites need to apply SSSL certificate?
(1) SSL certificate may be encrypted so as not to be leaked sensitive information
The main reason to use SSL certificate to protect sensitive information sent over the Internet can be encrypted to prevent important data from being leaked. This is important, because you transfer information between your computer and a server on the Internet, if the SSL certificate encryption is not used, you pass any information you are likely to be accessible to third parties, including your credit card number, user name and password, and other sensitive information. With SSL certificate, you can guarantee everyone can not read the information, which can protect data against information *** or bad faith of the people of the infringement.
(2) SSL certificates can provide authentication to prevent phishing sites
In addition to encryption, SSL certificates can provide authentication. This means that you can ensure that the information is sent to the correct server, do not worry about someone stealing your information. Effectively prevent third parties masquerading as your website and deceive your users, access to personal information, resulting in large or small loss. The SSL certificate is issued by a CA trusted authority, and will strictly verify the information business / organization applying for the certificate.
So, choose a trusted CA SSL certificate issued by the agency is very important, a CA will only issue SSL certificates verify all kinds of information, and EV SSL certificates require more information than other verification certificate.
(3) SSL certificates increase trust, eliminate browser "unsafe" prompt
Earlier in Google browser blow http site, the SSL certificate is not installed in the http site, suggesting that "unsafe" logo, as shown below, very much affect the user experience, the loss of a large number of website traffic.
SSL certificate installed sites can be displayed in the Web browser address bar, small green lock icon in the address bar green, EV SSL certificates can also display the company / organization name. To ensure that visitors know that the connection is protected, you can be assured. This means that when visitors see these tips will be more likely to trust your website. And you can view the information issued by the CA mechanism, in order to provide more confidence for your customers.
(4) in favor of keyword ranking seo
Google, Baidu and other browsers, the site made it clear that the right to install SSL certificate being ranked priority, so unless the site of the SSL certificate is installed, otherwise it will be difficult to find a site in the search engine forward position, thus affecting traffic to the site and income.
How to choose the SSL certificate?
First, consider the number of domain names they own, a single domain name on the choice of single-domain SSL certificates, multiple primary domains will now multi-domain certificate, a domain name with multiple sub-domains for now wildcard certificate.
Second, consider the authentication, if it is a personal blog websites, it can only select DV SSL certificate because the OV / EV needs to verify that information, individuals can not provide such information. Business users, EMC certificate is recommended to choose OV, EV SSL certificates, more reliable, and EV SSL Certificates can display the business name, in favor of brand promotion, giving users a sense of trust in the browser address bar.
1. Website: If you run a small personal website owners or individuals from the media, but did not need to ask too much HTTPS sites for credibility, then you can select the domain validation certificates (DV). Fast DV certificate issued speed, low price, usually can be completed within ten minutes issued, without the complexity of website authentication process, and support HTTPS security padlock, cost-effective.
2, corporate website: If you run a common corporate websites, involving registration, login, etc. Member Center page, it is recommended to use the Enterprise SSL certificate type (OV) or Enhanced SSL certificates (EV). Both certificates are required on the identity of the website owner is authenticated, be able to prove the true identity of the website, put an end to phishing sites, and have better protection of personal information of visitors. EV certificates will make the website address bar turns green, which will help promote the brand, more likely to win the trust of customers. 
3, the electricity supplier sites: the electricity supplier for the class Web site, the user's security information website and brand image are key factors for purchasing SSL certificates. Electricity supplier websites involved in the payment transaction, customer privacy and account information such as passwords, encryption requires a higher level. And electricity supplier larger class website traffic, brand image is more important, it is recommended to use Professional Edition Enterprise SSL certificate type (OV) or Professional Edition Enhanced SSL certificates (EV).
4, financial website: financial securities, banking, third-party payment sites typically require the highest level of security, not only related to the user's private information, credit card information, payment security, but for the true identity of the site has a high demand for standards . Enhanced Extended Validation certificates (EV) using the most appropriate financial website, EV SSL certificate means the certificate issued in compliance with global standards, strict site authentication, is the highest level of security of SSL certificates. And after the installation of EV certificates, the browser address bar green visual display unit and a Chinese name, safe and reliable at a glance.
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