DKIM is one of the security standards to improve email security and prevent phishing, spoofing, and email spam. This text explains what DKIM is, how DKIM works, DKIM records, why DKIM is essential, why you need to use DKIM, and answers DKIM FAQs.
What is DKIM?
DomainKeys Identified Mail, known as DKIM, is an email security standard. DKIM helps you detect if email conversations are secure by checking if the content of any email was manipulated during transit.
DKIM protects against phishing, email spoofing, and email spam by providing email security. It authenticates all emails to detect the addresses of the sender, allowing the recipient to verify if the email received is from a credible source and authorized by the domain’s owner. DKIM uses a digital signature, known as a DKIM signature, which is encrypted for security and added to the email’s header.
How Does DKIM Work?
DKIM allows you to take responsibility for sending emails by providing a unique signature with the email. The DKIM signature is verified at the receiver’s end using cryptographic authentication. The DKIM authentication process can be distinguished into three steps:
1. Creating a DKIM Signature: The email’s sender identifies the fields they wish to include in their DKIM signature.
2. Hash Generation: Once the DKIM signature is ready, all the text fields included in the signature are hashed by the sender’s email platform, resulting in a hash string. Hashing is the process of disguising regular values into hash values to keep original values safe from threat actors. The resulting hash string is encrypted using the sender’s private key.
3. Sending the Email: After hashing, the email message is sent where the recipient’s email provider validates the DKIM signature. This process involves finding the sender’s public key and decrypting the encrypted hash string to its original form. The recipient compares the decrypted hash string with another hash of the DKIM signature fields that it creates on its own.
If both the hash strings match, the recipient can conclude that the fields of the DKIM signature were not manipulated during email transit and that the email sender is authentic since the DKIM signature has been verified.
DKIM Records Explained
A DKIM record is a unique DNS (Domain Name System) TXT record which stores the sender’s public key. The recipient’s email server utilizes this public key to decrypt the hash string of the DKIM signature and verify the email sender.
DKIM records are provided by the email provider that your organization uses. A DNS record includes various information, including:
- Key Type
- Public Key
DKIM records are stored on DNS servers and are provided when the recipient’s mail server sends a query to the sender’s DNS records.
Why is DKIM Important?
The DKIM authentication process is vital for email security for two reasons.
1. Sender’s Legitimacy and Email Deliverability
Threat actors and scammers advocate the usage of email spoofing to spread malicious spam and phishing emails to target individuals. Such emails can easily lead to a loss of financial and personal information for any individual and even provide an entry point for threat actors to infiltrate the organizational network.
This is where DKIM comes into play. DKIM is more of an additional protection than a requirement. Since emails with DKIM signatures improve the legitimacy of your emails, they are less likely to be marked as spam or junk, enhancing email deliverability.
DKIM authentication works seamlessly with existing email infrastructures such as Postmark and ISPs (Internet Service Providers) such as Yahoo, AOL, Gmail, and others. DKIM can also be paired with SPF (Sender Policy Framework) and DMARC (Domain-based Message Authentication Reporting and Conformance) for a layered email security approach. Email servers not supporting DKIM signatures still receive DKIM-signed emails without causing trouble. Furthermore, DKIM is an email security standard that is adopted universally.
It would be best for you to add a DKIM record to the DNS to improve your emails’ legitimacy and email deliverability.
2. Improved Brand Reputation
ISPs trust DKIM to build and enhance their brand reputation, and it does the same for your organization, improving your brand name. If your emails are delivered with low spam bounces and high engagement, you will develop an excellent reputation for sending legitimate emails with ISPs, improving email deliverability further.
It would be best to note that DKIM does aid in verifying the sender’s legitimacy and ensuring that the email content has not been manipulated. However, DKIM does not encrypt the contents of your email message. This is done by TLS.
TLS (Transport Layer Security) is a cryptographic protocol ESPs (Email Service Providers) use to encrypt email messages between the sender and receiver during transit. DKIM is also compatible with this process since a DKIM signature remains in the email header without encrypting your email’s content.
DKIM FAQs Answered
Now that you know what DKIM is and how DKIM works, here are the answers to common DKIM questions that will clear any doubts you may have.
1. What is DKIM?
DomainKeys Identified Mail is an email security standard that you can use to sign emails and verify to detect if email messages were manipulated in transit. DKIM uses public-key cryptography and improves email deliverability and security, increasing your domain’s reputation.
2. What is a DKIM record?
A DKIM record is a TXT file kept on the email sender’s DNS. The DKIM record includes the public key of the sender that the recipient’s mail server can use to decrypt the sender’s DKIM signature and verify the email’s authenticity.
3. Does DKIM implementation require a certificate?
No, you do not need a certificate for DKIM, as it requires creating, setting, and destroying keys.
4. Does DKIM provide end-to-end encryption for email messages?
No, DKIM only verifies that the message has not been altered by checking the DKIM signature. It does not encrypt the email message.
5. Can I have multiple DKIM records?
Yes, your domain can have more than one DKIM record. Each DKIM key will have its unique DKIM selector, also added to the DKIM signature, so the recipient’s mail server knows which DKIM key is required for verification.
DKIM is one of the best and quickest methods to improve email security and deliverability. Organizations should implement DKIM since it allows recipients to verify email senders and flag malicious or spam content. DKIM provides one of the most effective ways to steer clear of phishing, spam, and spoofing emails, serving as an essential step for enhancing any organization’s email security.