Public vs Private Certificate Authority

Rashmi Bhardwaj | Blog,Security

A Certificate Authority or CA is basically an entity or institution that is authorized and responsible for the distribution of digital certificates. The issuance of certificate is one of the important segments of securing the interactions taking place over the Internet. Why is it that these certificates help in recognizing the identity of someone over the Internet? Well, the certificate cryptographically tie up an identity with public key.

The primary use of certificates is in SSL encryption, in order to authenticate the devices as well as the people and to legitimize codes and documents. One of the unique features of a trusted certificate authority is ‘ubiquity’. It is necessary for it to be as compatible with different versions of Internet browsers and operating systems as possible. It is essential to deploy uninterrupted validation of the certificate to various users across any sort of service or device.

If we talk in a layman term, “what do CA (certificate authorities) execute?” They ensure everyone over Internet is who they claim to be they are!


The Types of Certificate Authority

 There are two basic kinds of certificate authorities that we are going to discuss right over here. One is public certificate authority and the other is private certificate authority. The point that we are going to discuss down below is differentiating public vs private certificate authority.

So let us find about the same-

A Public CA is a certificate authority rendering services to the common public and any organization offering CA features and services to you that you are not associated with is basically a Public CA. Most of the public CAs are basically companies that have earned the faith of the public at large. There are some public CAs operated by the governments as well.  On the other hand, Private CAs, also termed as local CAs, are a form of self-hosted certificate authorities meant only for internal usage. Private CAs have been provided limited scope intentionally, which is usually employed within an organization, a very large company or even a university. It is a fact that the private CA is only ‘trusted’ by users inside that organization – and it rarely interfaces with the outside networks.

As you are often required to pay for each of the certificate issued, Public CAs are the favourite option in case you have to release a limited number of certificates. On the other hand, in case you forecast a high volume of certificates, just because the organization is massive or rather the certs required to be reissued on frequent basis, it can be reasonable and cheaper to operate your own CA instead of paying for every release issued by public CA. Another aspect which is different between both CA types is wrt nature of communication i.e. Public CA is the go-to solution under any case where the situation demands transparent communication on the Internet. In case of any public-facing service or product, you will require a public CA. Private CA approach is more secured. Having control on certificate expiration period is an important factor for organizations that do have a time-sensitive or cynical nature.

Let’s understands which one is more secured – Public certificate authority is widely used utility over the Internet. Most kinds of privacy or security include a public form of CA in one way or the other. This is not the case with Private CA – They are significantly more secure in comparison of public counterparts. In Public CAs, certificates are handed out to anyone who pays, the private CAs limit their certificates only to specific devices or people, generally those inside the organization.

Some examples of Pubic Certificate Authority are while Implementing SSL, encrypting emails and signing digital documents. On the other contrary, Private Certificate Authority is a vital part of building a secure and robust intranet (i.e. internal network).

Public vs Private Certificate Authority

Marking the Difference

The table differentiating public vs private certificate authority has taken into consideration various aspects associated with the certificate forms. Right from the utility to the security features, both public and private CAs have been measured to deliver best understanding. Hope, it would have answered much of your questions.


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