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A Beginner's Guide to All Types of SSL Certificates


SSL Certificates

Wildcard SSL

Multi-domain SSL


CasiileJanuary 25 2022

If you are browsing the websites or shopping online, will you continue to visit the website when an insecure warning suddenly pops up? I guess that most people would choose to close this insecure site. Because of the rampant Internet fraud, website security is what visitors and enterprises is the greatest concern.

How do you know if you can trust a website with your private data? That is what SSL Certificate does. Now let's learn what SSL certificate is and how it helps protect your online business. 

What is an SSL Certificate?

An SSL (Secure Sockets Layer) Certificate is a data file that provides an extra layer of security between a website and a browser. An SSL certificate both serves to authenticate the website’s identity, and to encrypt any information provided through the website. Both of these functions are important security measures to thwart hackers that may want to take over the website, or intercept information your visitors provide during the checkout process or in a form.  

Why do you need an SSL Certificate?

SSL certificates are the backbone of security and trust on the Internet. SSL certificates protect your sensitive information such as usernames, passwords etc. In general, all SSL certificates on have the following benefits:

  • Get the strongest security coming with SHA256 Hash Signing Algorithm and 2048-bit RSA Private key
  • Begin with https:// instead of http:// and attach a secured padlock icon in the address bar
  • Boost Google search engine rankings if your website is installed SSL certificate
  • Acquire a static or smart secure seal issued by CAs to earn the trust of website users
  • World-class technical support and customer team at your service 7/24
  • 30-day money back guarantee
  • Up to $1,750,000 in warranty provided by CA. (Tips: the warranty is different for different CAs and types of certificates.)

What are the types of SSL certificates?

When you consider installing any of seven types of SSL certificates on a single Web server or multiple servers, you need to know which type of certificate is best and suitable for your site.

Generally, SSL certificates are classified in three ways: encryption and validation, domain number, encryption algorithm.

Based on encryption and validation level

SSL certificates are differentiated into three types based on the validation level: Domain Validation, Organization Validation, and Extended Validation.

Domain Validation (DV) SSL Certificate

DV SSL is the most common and basic SSL Certificate type. Everything you need to do to get a DV certificate is to prove you are the owner of the domain. And then you will obtain your DV certificate issued by CA in as little as five minutes.

DV SSL certificates provide industry-standard encrypted security and entry-level credibility, making them ideal for internal testing sites, personal blogs, small and micro business sites, etc. However, it is not a best option for e-commerce and those sites that process sensitive data or transactional information. You had better deploy an Extended Validation certificate for these sites. Putting aside advantages mentioned above, you are able to benefit more from our DV SSL certificates in NicSRS:

  • Authentication of the domain ownership
  • Minimum warranty of $100,000
  • Unlimited sever licenses

Generally speaking, Domain Control Validation (DCV) is used by CA before issuing an SSL certificate to verify who own the domain. DCV is completed in three available ways: Email based, DNS based and HTTPS/HTTP Hashing. Click How to complete Domain Control Validation.

Organization Validation (OV) SSL Certificate

Organization Validation certificate is a kind of SSL certificates to verify the real identity of the entity to which the website belongs. This kind of certificate can not only play the role in encrypting the confidential information of the website, but also prove the authentication of the website to users. It is suitable for e-commerce websites, small and medium-sized businesses.

The process of getting OV SSL certificate is a bit longer than that of DV certificate, since CA will verify your domain and organization. Moreover, it is more expensive than DV, for providing an extra online trust to you customers. Here are organization validation requirements:

  • First Step – Domain Validation: to verify the ownership of your registered domain name;
  • Second Step – Organization Validation: to check your company’s registration information to make sure identity of your legal entity via public 3rd party databases;
  • Third Step – Telephone Verification: to confirm Certificate Signing Request (CSR) information by calling you via the phone number posted in public 3rd party databases.

Furthermore, our OV SSL certificates bundle with more features.

  • Higher security and more trust

  • Maximum warranty of $1,500,000

  • Multiple servers licenses without limitation

Extended Validation (EV) SSL Certificate


Extended Validation SSL certificate is the most valuable certificate with the best SSL security and website identity assurance. When users access to websites with EV SSL certificates deployed, these prominent indicators will visible; that is, a secure padlock image and your verified company name displayed in address bar. Your brand statement will show your customers that you're authentic company who they love to do business with. Accordingly, more credibility leads to more conversions and orders for you!

Undoubtedly, EV SSL certificate is the first choice for e-commerce or financial enterprises, which can effectively improve the credibility of the website, enhance the trust of visitors, improve the conversion rate, and result in more online orders!

CA will serve a thorough investigation before issuing an EV SSL certificate, which has more stringent requirements than DV SSL and OV SSL certificate. However, its verification process is mostly the same as OV SSL, including domain ownership, legal existence, physical location, verification call. Some Certificate Authorities require applicants to fill in additional agreements to further confirm their information.

Compared with OV SSL, Extended Validation certificate offer you more pros:

  • A green address bar (maybe gray in some browsers) and a security padlock symbol;
    The authenticated company name shown in the address bar via a full business vetting procedures;
    Up to $1,750,000 in warranties.

The differences are shown clearly here:

Based on number of domain names

A regular SSL certificate protects a single site, that is a fully qualified domain name(FQDN). For example,,, and are all independent FQDNs. In addition to safeguard a FQDN, many enterprises have other types of domains, such as SAN domains and sub-domains. Which type of SSL certificates is cost-effective option to secure SAN domains or sub-domains? Here we go. These certificates can be classified into the following three types based on the number of domain names:

Single Domain Certificate

As the name suggests, a Single Domain Certificate applies to one domain only. For example, if you buy this certificate for, these domains like or cannot be secured. The Single Domain certificate is commonly used to secure:

  • A main domain with WWW or non-WWW(e.g:,
  • OR a single subdomain. (e.g :

Single domain SSL certificates are usable in three validation levels: DV, OV and EV SSL certificate.

Wildcard SSL Certificate


Wildcard SSL certificates are used to protect secondary subdomains under the same main domain. There is no limit to the number of subdomains that can be protected on a single wildcard certificate, whether 2 or 5,000 subdomains.

For example, a Wildcard certificate of could also cover unlimited subdomains like and and allow you to added more subdomains with growing online business. Even though it is costlier than a Single Certificate, Wildcard certificate is more affordable than getting plentiful separate single certificates for every sub-domain.

With a Wildcard SSL Certificate in your site, you would benefit a lot:

  • Protect unlimited secondary subdomains;
  • Secure automatically additional subdomains without re-verification or extra fees;
  • Lighten the SSL certificate management workload;
  • Offer a warranty of up to $1,500,000;
  • Install on multiple servers.

Either DV Wildcard or OV Wildcard certificate is alternative for you. Which validation level is the best? Please determine based on your business requirements. 

Multi-Domain SSL Certificate 

Multi-Domain SSL Certificate is a nice way to protect multiple domains. For example, if you have as your main domain and also have, and, you can use a Multi-Domain certificate to protect these different top-level domains (TLDs); that is also called SAN certificate.

If your site uses a Microsoft Exchange or Office Communications Server, you may need to choose a unified communications certificate (UCC). This type of certificate was originally designed for Microsoft Exchange servers, so it is recommended to use UCC for Websites running on the mentioned Web server. However, UCC is now recognized by multiple servers and can often be deployed across other servers.

Differing from Wildcard Certificate, SAN/UCC supports all validation levels, and come up with more features:

  • Protect multiple domains (SANs)
  • Provide a trusted site seal from the CA
  • A maximum warranty of $1,750,000
  • Simplify certificate management & save money
  • Offer unlimited server licenses

Multi-Domain Wildcard SSL Certificate

A Multi-Domain Wildcard SSL certificate is the most omnipotent solution that will secure multiple main domains and their subdomains under a single installation. Simultaneously, you can enjoy the pros of both multi-domain and wildcard certificates. Depending on different CAs, you can add up to 250 SAN wildcard domains during the life-cycle of the single certificate. Therefore, this certificate will extremely save you a lot of time, money and workload.

  • Powerful 256-bit encryption
  • Activate SSL visual indicators
  • Secure up to 250 wildcard domains and unlimited sub-domains

Multi-Domain Wildcard SSL certificates support two validation methods: DV SSL and OV SSL certificate. That's more than enough to cover almost all online projects, from basic websites and blogs to online stores and large systems.

Please look at this picture below:

Based on Encryption Algorithms: ECC and RSA

The types of SSL certificates are classified by digital signature algorithms: RSA encryption algorithm and elliptic curve cryptography (ECC) algorithm. 

  • In terms of usage, RSA predates ECC, and RSA has always supported SSL certificates encryption.
  • In terms of mathematical calculations at specific points on elliptic curves, ECC is securer and better than RSA.
  • In terms of private keys, RSA requires a long private key to remain algorithm secure. The longer the private key, the lower the computing efficiency. Unlike RSA, ECC has shorter private keys, which reduces computational overhead and improves security.

Despite ECC is superior in many aspects, many websites still choose SSL certificates based on RSA algorithms, because RSA is widely supported by Web Servers and Hosting Companies. 

  • If you like SSL certificates based on RSA algorithm, all SSL on can meet your needs.
  • If you prefer certificates based on ECC algorithm, most CAs from our authorized platform can provide ECC certificates, such as Sectigo(formed Comodo), Digicert (Symantec), GlobalSign, etc.

No matter what algorithm certificate you need, will help you.

That's a comprehensive introduction of SSL certificate of all types. To sum up, no matter which type of SSL certificate you choose, you should know what it is and why it is best for your website. If you are not sure how to choose SSL certificates, don’t be hesitated to contact us!