Skip to content

What is DKIM and how does it work?

What is DKIM authentication? Learn about what DKIM signatures are and how they can help secure your messages.

Spoofing is one of the most common scams that impact businesses and consumers alike. This is when a hacker hides their true email and uses a company’s domain email, and often some very convincing visuals, to fool its customers into providing personal information. 

This practice creates some serious issues. Cyber scams have resulted in more than $10 billion in annual losses, many of them attributed to spoofing. The good news is that there are ways to protect your brand and your clients from email-related scams. One of the most effective is known as DKIM authentication.  

Jump to:

What is DKIM?

Domain keys identified mail (DKIM) is a type of email authentication. Its function is to guarantee that nothing has intercepted or tampered with the email the end user receives—in other words, that hackers haven’t intercepted the email to make changes to the “from” address in an attempt to scam the receiver. 

How does DKIM authentication work? 

DKIM authentication works by giving an email recipient a way to verify that it actually came from the authorized sender. To do so, emails that use DKIM authentication include a cryptographic signature (an encrypted header) added to each message. 

So, how does the receiver decrypt the header, or DKIM signature, to verify the authenticity of the sender?

The domain owner adds a DKIM record, also known as the DKIM key, to its domain name system (DNS) record. The domain owner can choose to add as many DKIM records as they’d like without a need for any special certifications. The email recipient’s server can access this record and use its public key to decrypt the header’s DKIM signature, thereby verifying its authenticity. 

Keep in mind, DKIM doesn’t offer end-to-end encryption. It simply proves the message left the sending server and made it to the receiving server without being intercepted and tampered with. The only encryption involved in DKIM authentication is the encrypted DKIM signature in the email’s header. 

Pro tip

If you’re a domain owner, you can test your DKIM records and signature with one of many free DKIM analyzers on the web.

What is a DKIM signature?

A DKIM signature is an encrypted header that mail servers add to emails before sending. The receiving server uses the private keys that the sender provided in its DNS record to decrypt and validate the signature.  

What is a DKIM selector?

DKIM selectors are sets of instructions from the sender’s DNS record that tell the receiving mail server which specific DKIM public key record it should use to decrypt the DKIM signature. The DKIM selector appears as an “s=” tag in the DKIM signature. 

Why is a DKIM important?

There are several reasons why it’s important to use DKIM signatures for your business’s emails. Not only do they help prevent your emails from falling into a spam folder, but they could also protect your clients from malicious attacks. 

Avoid spam folders

The last thing you want is for messages you send to your clients to end up in spam folders. That’s a waste of time and money, and it could result in your clients missing out on important updates. This can lead to a poor user experience that may damage your credibility and reputation. 

When you use DKIM signatures, you don’t pique the interest of spam email filters

Why? The reason is simple. When the recipient server receives a message with a DKIM signature, it’s able to validate the sender’s identity. This validation will prove that you’re a real sender, not a spam bot, so you’ll make it into most inboxes. So, be sure to steer clear of being spammy with your email marketing. 

Prevent spoofing and phishing attacks

Scammers send more than 3 billion phishing emails every single day. No wonder these emails cost the U.S. economy billions of dollars per year. The good news is that there are several ways to defend yourself and your clients against phishing attacks. 

DKIM signatures are one way to reduce the chances of your clients becoming data phishing victims. That’s because, when you use them, your clients’ incoming mail servers will be able to recognize the difference between your emails and the ones that are phishing for data. 

Moreover, these DKIM signatures can also prevent spoofing attacks, in which scammers hide their real email behind a fake company email address. Since you’re using DKIM signatures, the receiving server will have a way to determine if the message is valid, throwing all fake messages that only appear to be from your domain name right into the spam folder. 

Increase your email integrity

Sometimes scammers will attempt to hack an email as it travels from point A to point B. If they succeed, they will be able to tamper with the message. This can become a significant problem for you and your clients. 

DKIM signatures only show up if no one has tampered with the final message. As such, you can be sure that using them will protect your messages from interception and interference before they reach your clients. 

Is DKIM all you need for completely secure emails?

DKIM authentication is an important aspect of creating a meaningful email security ecosystem for your business, but it’s not the only aspect you should consider. DKIM can work with other email authentication standards like domain-based message authentication, reporting and conformance (DMARC), and sender policy framework (SPF). It’s important to use all available email authentication standards to ensure that your sending domain gains and maintains a positive reputation for thoroughness and strong email deliverability

What are the differences between DKIM, SPF, and DMARC authentication?

Here’s a breakdown of the differences between these three common types of email authentication:

  • DKIM: This method adds a digital signature, verifying that the email was sent by the domain it says it’s from. It also verifies that the email wasn’t changed in transit. 
  • SPF: This type of authentication verifies the sending mail server by looking for it in a list of the domain’s authorized servers. If the server doesn’t appear, SPF blocks the email or sends it to spam. 
  • DMARC: This approach takes advantage of both technologies. Most notably, DMARC authentication tells email receivers how they should handle unauthenticated messages. So, while DKIM and SPF offer their own layers of security, DMARC makes it possible to give the receiving server-specific instructions about how to handle incoming mail. This helps to further reduce the risk of their domain being used in spoofing or phishing attacks. 

How HoneyBook can help

HoneyBook is a complete clientflow management platform. When you use HoneyBook, you’re able to manage all of your client touchpoints in one place, including filtering, viewing, and sending client emails. If you use a custom domain name through Gmail, you can use HoneyBook’s authentication tracker to ensure your emails are authenticated and your clients receive your transaction emails—every time.

Start your free trial now to see how HoneyBook can help you better manage your email-based client communications along with all other client flow tasks. 

Stay current on email best practices

Get the top tips on independent business management straight from the experts.

Blog tags:

Share to:


Follow us

Related posts