The Role of DKIM in Securing Email Domains

The Role of DKIM in Securing Email Domains


Emails are the source of transmitting malware and various cyber-attacks to exploit data of users. This is DKIM (Domain Keys Identified Mail) plays its role. DKIM is an email authentication protocol, designed to detect fraudulent activities like email spoofing. This email security system lets an organization take the responsibility of messages that are in transit.

Phishing attacks like “man in the middle attack” have been infamous for manipulating email messages before they reach their designated recipients. The need for this email security protocols arises because these attackers cleverly forge email addresses and its contents. Their vicious motive is to deploy email spamming, phishing and email-based fraud activities.

DKIM for Email Security

This email authentication protocol works by affiliating a digital signature that is attached to the domain name of every outgoing email. The recipient system further verifies that digital signature by checking the sender’s public key, published in DNS (Domain Name Server).

The point of having a digital signature is to check the email’s legitimacy. It also guarantees that some parts of email like attachments have not been altered during the transit. DKIM signatures are usually not visible to end-users and are verified by the infrastructure instead of the message’s author.

How DKIM Works?

  • Digital Signature

The very first step involves the signature process. It is required for the sender to decide and allocate the elements that should be included in the process of signing. These elements should not be changed or else the DKIM authentication to forward an email, fails.

  • Encryption

In the encryption process, the readable content of the email is converted into a unique textual string via cryptography. The hash string is then encrypted with the help of a private key, which is assigned to a unique combination of domain and selector. This further allows users to create several other private keys for the same domain. The email message is sent after encryption and only the sender gets to access the private key.

  • Validation

After receiving emails, the mailbox provider performs a DMS query to the check public key for that combination of domain/selector. The public key is unique and is the only match for the private key that is assigned in the email. This key pair match enables the email provider in decrypting the DKIM back to the original hash string.*fYOOdY1qPawWWgjL.jpg

What is DKIM Record?

DKIM record a combination of the selector and public key. In order to implement this security portal, a DKIM record is set on the Domain Name Server. However, the sending mail server signs email with a private key. Whereas, receiving mail server verifies the signature by using the public key in the domain’s DNS for information.

Why Implementation of DKIM is Important?

Hackers are a pro at impersonating as legitimate domains to deploy malicious scams or phishing campaigns. With advancing technologies, hackers have advanced their techniques to deploy cyber-attacks as well. But DKIM makes it hard for hackers to use domains that have DKIM protection against such illegal actions.

Along with SPF and DMARC email infrastructures, DKIM offers layered protection for domains sending emails. Although implementing it isn’t easy but it guarantees that domain visible to the end-user remains the same and validated by security systems. It helps mailbox providers in detecting emails that are authenticated and which are not.

KDMARC for DKIM Implementation

DKIM Online Check Tool

One domain can have several DKIM keys, publicly listed in DNS, but every matching private key has got only one mail server. You can verify your it with DKIM online check tool KDMARC, an advanced analytical tool by Kratikal.

This ingenious tool verifies your SPF and DKIM records automatically. KDMARC has a DKIM selector field where the user just has to add the first part from the subdomain under which it is implemented. For example, if your DKIM is at then “google” is the DKIM selector.

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