What Is a Comodo S MIME Certificate?

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Let’s break down what an S/MIME certificate is and how it works to protect your business

Ever heard of an “S MIME certificate” or a “Comodo SMIME certificate?” How about an “S/MIME certificate?” All three are basically the same thing — the difference is that one of them just happens to include a trusted certificate authority’s (CA’s) name, and one of the terms is written with a forward slash (/) in it. So, this means a Comodo S/MIME certificate is an S/MIME certificate that’s issued by Comodo CA.

Yeah, those are the only differences between the terms. Some people write “S/MIME” as “S MIME” and others writer it all as one word like “SMIME.” But this may leave you wondering one important question: What is S/MIME?”

Regardless of how you choose to write it, here’s what you should know about what this type of certificate is, what it does, and what specifically a Comodo S/MIME certificate entails.

What is an S MIME Certificate?

Here’s the short and the long of it — an S/MIME certificate is a digital certificate that secures email messages and asserts identity. A bit more of an in-description is that it’s an email signing certificate that individuals and organizations use to digitally sign their emails and/or encrypt the content of their messages. You can choose to sign or encrypt your emails — or do both — with your certificate. The choice is up to you and what you wish to do with it.

S/MIME itself is an acronym that stands for “secure/multipurpose internet mail extension.” This refers to an email signing protocol that’s used to sign MIME data such as the header and body of emails.

Email encryption helps to protect your business against cybercriminals by:

  • mitigating man-in-the-middle (MitM) attacks,
  • preventing email spoofing and phishing.

Using an S/MIME cert also helps you be compliant with industry regulations relating to email security and transmitting individuals’ personal or financial information or data. This includes DFARS, GDPR, and HIPAA.

If you’re concerned that your email client won’t be able to handle an email signing certificate, then we have great news for you. Many of the major email platforms support S/MIME certificates, including Outlook, Thunderbird, and Apple Mail!

While the benefits of using an S/MIME certificate sound great, how does it all work?

How Does an Email Signing Certificate Work?

The way that the certificates encrypt emails is through the use of asymmetric encryption, or what’s also referred to as public key encryption. Essentially, an email is digitally signed using a private key and authenticated with the recipient’s public key.

This public key is then sent to the recipient along with the encrypted email, which allows your email recipient to verify that it actually came from you and not an imposter. The recipient then can use their corresponding private key to decrypt the message and access the information.

How an S/MIME Certificate Differs from SSL/TLS

While both are based on public key encryption, an S/MIME certificate provides valuable end-to-end encryption to protect data at rest. This differs from an SSL/TLS certificate, which provides data in transit protection only. When it comes to email security, the differences between the two certificates include the following:

  • an S/MIME certificate is an endpoint certificate that’s issued to a specific individual within an organization.
  • an SSL/TLS certificate is something you install on a web server (to secure the email server).
  • an S/MIME certificate allows you to encrypt the message and attachments within your email before it ever leaves your mailbox.
  • an SSL/TLS certificate, when installed on your email web server, would only protect the content of the email while it’s in transit.

Who or What is Comodo CA?

Comodo CA, now Sectigo, is a reputable third-party certificate authority (CA) that web browsers and platforms trust. They’re also the world’s biggest CA. In their role, Comodo CA issues all types of X.509 digital certificates such as SSL/TLS certificates, code signing certificates, and S/MIME email signing certificates.

As far as Comodo S/MIME certificates go, they like to do things a little differently. They refer to their email signing certificates as Comodo personal authentication certificates, or CPACs. They also offer three types of CPACs to meet the needs of individuals, organizations, and enterprises:

CPAC Basic CPAC Pro CPAC Enterprise
Validation Requirements Domain Control Domain Control

Identity Verification

Domain Control

Identity Verification

Organization Validation

Certificate Fields [email protected] [email protected]

First Name, Last Name

[email protected]

First Name, Last Name

Company Name

Company Address

Email Encryption Yes Yes Yes
Email Signing Yes Yes Yes
Document Signing Yes Yes Yes
Client Authentication Yes Yes Yes
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As you can see, the biggest differences between the three certificates — aside from the prices — are the validation requirements and the fields of information each certificate provides.

The basic certificates are available for as little as $9.98 per year. A CPAC Pro certificate starts at $31.71 per year. For Enterprise users, for just another $10 per year ($41.79 per year), you can take advantage of a CPAC Enterprise certificate to secure your email.

See what a Comodo S/MIME certificate can do for your business:

Purchase a Comodo S/MIME Certificate & Save Up to 74%!

We offer the best discount on Comodo Personal Authentication Certificates (CPACs). Prices start at as little as $9.98 per year.

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