Digital Signature vs Digital Certificate — A Look at the Differences

We’ll break down the differences between a digital certificate vs signature and how each plays a role in cybersecurity

If you’re not sure how to recognize a digital signature vs a digital certificate, then don’t worry, you’re in the right place. The digital signature and digital certificate are both the fundamental concepts within the realm of cybersecurity.

There is a fundamental difference between a digital certificate vs. a signature. Digital certificates are all X.509 certificates issued by a publicly trusted certificate authority (CA). On the other hand, a digital signature is a unique numeric string that identifies the signatory. A digital certificate is signed using a digital signature.

In this article, we’ll explain everything about the digital signature vs digital certificate and how they are used in the real life to secure and authenticate emails, software, and websites., and emails.

What’s the Difference Between a Digital Signature and a Digital Certificate?

In general, the term digital certificate describes all X.509 certificates. It’s a list that includes an SSL/TLS certificates, email signing certificates, code signing certificates, and document signing certificates.

A digital signature is a unique numeric string that can be affixed to a digital certificate to validate the identity of the signer. It’s kind of like how your degree certificate contains the signature of the dean or principle of the school. Or, how you need to get official documents signed and stamped by a notary.

So, when we talk about comparing a digital signature vs a digital certificate, we first need to understand that they’re both different facets of the same thing — much like how your bank check can’t be used until you sign on it. But you need a check to sign that displays your official account and bank routing information to complete a financial transaction. You can’t put your signature on any other piece of paper and use it as a bank check, obviously!

In the same way, a digital certificate might be a server certificate or a client certificate. Regardless of which type of certificate you choose, it must be digitally signed by a publicly trusted certificate authority (CA) for browsers, email clients, and Windows SmartScreen to trust it.

Let’s understand how digital certificates and digital signatures work with various types of technology.

Digital Signature vs Digital Certificate: Email Signing Certificate

An email digital signature certificate, also known as email signing certificate or S/MIME certificate, is a digital certificate that organizations use to boost email security. Much like other X.509 digital certificates, it relies on the principles of public key infrastructure (PKI) to encrypt and decrypt the emails. This provides end-to-end encryption, which enables your email information to remain secure both while it’s at rest and in transit.

When a user installs an S/MIME certificate on their email client, they get the ability to embed their digital signature on the emails. The recipients will see a small ribbon icon in the email. When they click on the icon, it will show the sender’s name, email address, and original email subject. The digital signature provides assurance of the sender’s identity.

When the user sends an email, the email contents, along with the digital signature, get hashed, and the hash value is encrypted. What it means is that if anyone tries to tamper with the email contents or the digital signature while the email is in transit or at rest, the hash value changes, and the recipients would instantly know about it. This helps to protect the integrity of the email.

Digital Signature vs Digital Certificate: Code Signing Certificate

A code signing certificate is a digital file that protects downloadable software, device drivers, applications, executables, and scripts.

A code-signing certificate allows a developer or publisher to put a unique digital signature on the piece of software they develop using their private keys. This digital signature, along with the entire content of the software, gets hashed. No one can replicate, alter, or delete this digital signature when the software is in transit. If the digital signature or the content of the software is modified in any way, the hash value changes and the user receives a security warning.

When a user tries to download software from the internet, a Windows SmartScreen security warning box pops up. If the software is signed using a code signing certificate, it will show the software publisher’s name as a “verified issuer.” If not, the publisher’s name would be shown as “unknown” or “unverified.”

Digital Signature vs Digital Certificate: SSL/TLS Certificates

An SSL certificate (or, more accurately, a TLS certificate) protects the data transmission between a website and a browser by creating a secure, encrypted communication channel. Much like other X.509 digital certificates, an SSL certificate also needs a digital signature. It can be signed by the publicly verified certificate authority (what’s known as a CA signed certificate) or the users themselves (aka a self-signed certificate).

So, how does this work? After a user purchases an SSL certificate, they send an unsigned certificate via a certificate signing request (CSR) to the certificate authority. The CA verifies the information provided in the CSR as well as the applicant’s domain ownership. After the successful validation process, the CA inserts its’ digital signature using its intermediate root certificate’s private keys.

All the browsers have a root store in which the CA’s trusted root and intermediate root certificates are pre-downloaded. When a user tries to open a website, the browser verifies the CA’s digital signature by using this root store. If it can’t find the matching root CA (or chain of certificates) in its root store, the browser will display an error page “your connection is not private.”

Final Thoughts

We hope you have found this article useful for understanding the difference between a digital signature vs a digital certificate. The main takeaway here is that you need to buy a digital certificate, which will enable you or your CA to insert a digital signature, to protect your software, digital connections, and correspondences. If you get your digital certificate from SectigoStore.com, you will get up to an 80% discount on the retail price, 30-days money back guarantee, 24/7 live customer support, and much more!

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