What Is a Self Signed Certificate? Know the Advantages and Disadvantages

If you’re here because you’re wondering “what is a self signed certificate?” then you’re in luck. Not only can we explain what it is, but we can help you understand the advantages and disadvantages of self signed certificates!

A self-signed certificate is an SSL certificate not signed by a publicly trusted certificate authority (CA) but by one’s own private key. The certificate is not validated by a third party and is generally used in low-risk internal networks or in the software development phase.

But, first, a little background…

What is a Self Signed Certificate?

A self signed certificate (or “self-signed certificate” for all of the punctuation fans who are reading this article) is a digital certificate that’s not signed by a publicly trusted certificate authority (CA). This can include SSL/TLS certificates, code signing certificates, and S/MIME certificates. The reason why they’re considered different from traditional certificate-authority signed certificates is that they’re created, issued, and signed by the company or developer who is responsible for the website or software being signed. This is why self signed certificates are considered unsafe for public-facing websites and applications.

Most commonly, the term “self signed certificates” refers to self signed SSL certificates, which are also known as private SSL certificates. But as we mentioned earlier, the term also applies to other X.509 digital certificates.

A self-signed certificate is an SSL certificate not signed by a publicly trusted certificate authority (CA) but by one’s own private key. The certificate is not validated by a third party and is generally used in low-risk internal networks or in the software development phase.

Key Advantages and Disadvantages of a Self-Signed Certificate

Advantages of a Self-Signed SSL Certificate

• Self-signed SSL certificates are free.

• They’re suitable for internal (intranet) sites or testing environments.

• They encrypt the incoming and outgoing data with the same ciphers as any other paid SSL certificate.

Disadvantages of a Self-Signed SSL Certificate

• No browsers and operating systems trust self-signed certificates.

• The browsers will not show visual indicators of trust like a padlock symbol and HTTPS in front of the domain name.

• Your websites visitors have to proceed through a security warning page with error messages like “error_self_signed_cert” or “sec_error_untrusted_issuer” or “err_cert_authority_invalid” to access your content. This means that the users must manually click on the ”Accept Risk” button to open your website.

• Warning pages drastically affect the traffic on your website. If visitors don’t feel safe on your site, they’re bound to leave. This means they’re more likely to visit a competitor’s website and you could lose business.

• People feel cautious about sharing their personal information (such as credit card numbers, bank details, passwords, date of birth, phone number, email addresses, physical address, etc.) when a website is labeled as “not secure.”

• It’s easy for attackers to make self-signing certificates to perform man-in-the-middle (MitM) attacks. So, once the users bypass the security warning, they’re exposed to data theft and cyberattacks.

• Self signed certificates are highly risky for a website that offers paid subscriptions/memberships handles tax information or health records of users, accepts donations/charity or fundraising online or has an eCommerce facility.

Why Are Self Signed Certificates Not Trusted?

In public key infrastructure (PKI), the certificate authority must be trusted by both parties. i.e., browsers and servers. In order to retain trust, all CAs must follow the strict guidelines regarding validation, issuance, and revocation that are stipulated by the CA/B Forum. 

However, self signed certificates are not directly monitored by the CA/B Forum. Hence, there are many loopholes a hacker can exploit. For example, self-signed certificates usually have a one-year validity period. But you can’t trust the validity dates of a self-signed certificate because the user can always generate and sign a new certificate containing a valid date range. Another example is the revocation ambiguity. With a CA-issued certificate, the CA has the authority to revoke the certificate immediately if it is misused or the private keys are compromised. The revocation procedures of self signed certificates are as complicated as revoking an entire certificate authority!

Let’s take a real-life scenario here. In the U.S., the Department of Motor Vehicles (DMV) tests your driving skills before issuing a driver’s license to you. What if you print a piece of paper on your home printer with a line “I certify that I know how to drive” and self-sign it? You might the best driver ever existed on this planet earth, but would any traffic authority trust your fake driver’s license? No way!

In much the same way, self-signed SSL certificates are signed by the certificate owner rather than a reputable CA. Browsers consider only certificates that are signed by trusted certificate authorities as trustworthy. When your certificate is signed by you, and browsers don’t know you (don’t take it personally), then they won’t trust the certificate. It’s really that simple!

Save on SSL Certificates from a Trusted CA

If saving money is the only reason for you to use a self-signed certificate, we have good news for you! Now, you can get the well-reputed certificate Sectigo’s SSL certificate starting from only $8.78/year!

All Sectigo SSL certificates are

• safe,
• trusted by all the major browsers,
• provide warranty and free site seals,
• remove warning pages and ‘not secure’ symbol from your website, and
• display a padlock symbol and HTTPS in front of your domain.