SSL vs. code signing certificates: how are they different?

Whether you’re an SSL newbie or an old hand, there are probably myriad topics related to online encryption that you don’t know about. One that causes a lot of confusion is the difference between SSL certificates and code signing certificates. Are they completely different or pretty much the same? In this article, we’ll clear up any confusion you may have, and you should leave with a better understanding of how each works and what exactly they’re used for.

Are they really so different?

SSL certificates and code signing certificates do share some similarities. The main one is that they are both a type of X.509 digital certificates underpinned by public key infrastructure (PKI), which is the framework that manages encryption and authentication across the online sphere. Both types of certificates are typically issued by trusted Certificate Authorities (CA), and the main purpose of both is to protect users from security threats. However, SSL certificates protect through encryption and authentication, whereas code signing certificates protect through authentication.

What exactly does this mean? To really understand, we’ll need to take a closer look at the main functions of both.

The function of SSL certificates

SSL certificates are used to create an encrypted connection between clients and servers. The most common scenario is to install an SSL on a website (server) so that when a user visits on their browser (client) all the information sent back and forth between the two is protected and rendered unreadable, meaning that it can’t be intercepted or deciphered by a third party. This whole process is known as encryption. 

Authentication is used during the encryption process when the browser checks if the server’s SSL certificate has a digital signature from a trusted CA, as well as its validity period (when it was issued and when it is due to expire) and its revocation status (whether the CA canceled it for any reason). Authentication also plays a role before you even get your SSL. When you purchase an SSL certificate, the CA will verify your identity before it signs (authenticates) your SSL and issues it to you. This is known as validation. There are three levels of validation to choose from, some of which are more extensive than others. The higher the level you opt for, the more information will be available in the SSL certificate itself. The three validation levels are:

1. Domain validation (DV): This verifies that you have ownership rights over the domain you want to secure.
2. Organization validation (OV): The CA will carry out checks to verify the company requesting the SSL.
3. Extended validation (EV): For registered businesses only, EV has the most in-depth validation process.

If you’ve ever tried to visit a website and received a warning from your browser that it’s “not secure”, it’s likely because the SSL has failed the authentication process in some way. This could be because the certificate has expired, has been revoked, or the issuing CA is not considered trustworthy. This is why it’s essential to keep your SSL up-to-date and ensure you get it from a CA that’s trusted by major web browsers, such as Namecheap’s partner CA Sectigo. 

To summarize, an SSL certificate is typically installed by a website owner to enable encryption on their site, while authentication is used to verify the owner’s identity or company and whether or not an SSL certificate is valid.

The function of code signing certificates

Unlike SSL certificates, code signing certificates are not used for encryption, only authentication. While SSL certificates are typically (but not always) used for website protection, code signing certificates are used to authenticate the identities of software developers and publishers to protect users from dodgy downloads that could damage their devices. If someone attempts to download an application, program, or update in which the publisher’s identity is unclear, browsers and operating systems will issue a warning stating that that the publisher could not be verified and that it may not be trustworthy. 

To ensure that users trust them, developers and publishers can use cryptography to add a digital signature to their software with a code signing certificate. By doing so, browsers and operating systems can check the signature, confirm a trusted CA verified it, and authenticate their identity. It also ensures that the software hasn’t been tampered with. 

Much like SSL certificate issuance, before publishers get their code signing certificate, the CA will authenticate their identity before issuing it. For code signing certificates, there are two types available: standard code signing certificates and EV code signing certificates.

Standard code signing certificates have an OV validation level and tend to be more affordable; however, you will need to build a good reputation before users stop receiving pesky warnings when they try to download your software. EV code signing certificates, on the other hand, will get rid of those warnings as soon as you sign your software. 

The main differences summed up

SSL certificates and code signing certificates are both X.509 digital certificates with pretty different purposes:

• SSL certificates encrypt and authenticate
• Code signing certificates only authenticate
• SSL certificates are mainly used to secure websites
• Code signing certificates are used by developers and publishers to sign software, letting users know it’s legit and avoid security warnings

The takeaway

Hopefully, you leave this article with a better understanding of the main differences between SSL and code signing certificates and which you need most for your purposes. If you need an SSL to enable encryption for your website, be sure to check out the range of SSL certificates Namecheap has to offer.