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What is DKIM?

Today, emails hold significant importance in our lives. So, it becomes our responsibility & necessity to protect them from cyber threats. And this is where DKIM comes into the picture. DKIM means DomainKeys Identified Mail. It is a method for authenticating emails. It allows businesses & individuals to take responsibility for the emails they send – reducing the risk of email cyber attacks. Let’s dig this deeper and answer the most asked question, i.e., what is DKIM. We will also learn about everything else related to it.

What is DKIM?

DKIM is an email authentication method that allows an organization to cryptographically sign its outgoing emails. This signature is added to the email’s header using encryption techniques, providing a unique identifier for that particular message. When the email reaches its destination server, the receiving system can use the public key published in the sender’s DNS records to verify the signature’s authenticity. If the signature is valid, it confirms that the email was indeed sent by the claimed sender and hasn’t been affected on the way.

Functions of DKIM

1. Authentication

One of the primary functions of DKIM is to authenticate the origin of an email. DKIM signs outgoing messages with a private key and puts the public key in the DNS records to enable receiving servers to verify the sender’s identity. This helps filter legitimate emails from fraudulent ones – reducing the likelihood of phishing attacks.

2. Integrity

DKIM also ensures the integrity of email content during transit. By digitally signing the email’s header & body, DKIM creates a unique hash value that changes if any part of the message is altered. Upon receiving the email, the recipient’s server can recalculate the hash and compare it with the original signature to verify if the email has been intact.

3. Reputation Management

Another function of DKIM is its role in maintaining the sender’s reputation. Since DKIM signatures are associated with specific domains, email receivers can track the reputation of these domains based on the quality of their email traffic. Businesses that consistently send authenticated emails have a better reputation, leading to improved deliverability and inbox placement rates.

Benefits of DKIM

1. Enhanced Security

DKIM helps reduce the risk of email fraud by verifying the authenticity of incoming emails. This ensures that users can trust the emails they receive, mitigating the chances of falling victim to malicious activities.

2. Improved Deliverability

Emails authenticated via DKIM generally bypass spam filters and reach recipients’ inboxes. Since DKIM-signed emails demonstrate legitimacy, email service providers are inclined to treat them favorably – resulting in better deliverability rates for legitimate senders.

3. Brand Protection

DKIM helps companies to protect their brand reputation by preventing unauthorized parties from sending emails on their behalf. By signing emails with their domain’s private key, companies establish ownership and accountability for their outgoing messages, safeguarding their brand identity from misuse.

4. Regulatory Compliance

Compliance with email authentication standards, such as DKIM, is often a requirement for regulatory frameworks like GDPR (General Data Protection Regulation) and HIPAA (Health Insurance Portability and Accountability Act). Implementing DKIM enhances security and ensures adherence to regulatory guidelines, minimizing the risk of non-compliance penalties.

5. Increased Trust

When recipients see emails that are authenticated with DKIM, they trust the content. This trust factor contributes to better engagement metrics and strengthens the overall relationship between senders & recipients.

What is DKIM Record?

A DKIM record is a DNS (Domain Name System) record containing the public key used to verify the authenticity of DKIM-signed emails. It is published in the sender’s DNS zone. It has the domain selector, encryption algorithm, and public-key information. When an email recipient’s server receives a DKIM-signed message, it retrieves the DKIM record from the sender’s DNS to validate the message’s signature.

What is DKIM Signature?

A DKIM signature is a cryptographic stamp added to an email’s header that verifies its authenticity & integrity. It is generated using the sender’s private key and information such as the signing domain, the selector, and the cryptographic hash of the email’s content. Recipient servers use the public key published in the sender’s DKIM record to decrypt and verify the signature – ensuring that the email originated from the claimed sender and hasn’t been altered during transmission.

What is DKIM Selector?

A DKIM selector is a string of characters added to the DKIM signature to specify which public key should be used for verification. It allows organizations to have multiple DKIM keys for different purposes or departments within the same domain. By including a selector in the DKIM signature, senders can indicate which public key the recipient server should use to validate the message – enabling more control over email authentication.

How Does DKIM Different from DMARC?

While DKIM & DMARC (Domain-based Message Authentication, Reporting, and Conformance) are both email authentication mechanisms, they serve different purposes and operate at separate stages of the email delivery process.


DKIM focuses on verifying the authenticity of individual emails by adding cryptographic signatures to their headers. It allows email recipients to validate the sender’s identity and ensure the message hasn’t been tampered with on the way.


Whereas DMARC is a policy framework that builds on DKIM and SPF (Sender Policy Framework) to provide domain owners visibility & control over how their email domains are used. It allows them to specify policies for handling emails that fail authentication checks and provides reporting mechanisms to monitor email authentication activity.

While DKIM addresses the technical aspect of email authentication by adding cryptographic signatures, DMARC focuses on policy enforcement and domain protection by defining rules for handling unauthenticated emails.

On the whole, DKIM & DMARC help businesses strengthen their email security posture and protect their domains from abuse & impersonation.


DKIM provides a reliable method for verifying the identity of email senders and protecting their messages. By implementing DKIM, you can strengthen your email security. Also, understanding the differences between DKIM & DMARC enables you to adopt a better approach to email authentication. Hope you can now answer what is DKIM. If you need help – connect with top server providers like Leasepacket.


What is a DKIM Record?

A DKIM record is a DNS record containing the public key used to verify DKIM-signed emails. It helps recipient servers validate the authenticity of incoming messages.

What is DKIM Signature?

A DKIM signature is a cryptographic stamp added to an email’s header to ensure its authenticity & integrity. It confirms that the email originated from the claimed sender and hasn’t been tampered with during transmission.

What is DKIM selector?

A DKIM selector is a string of characters included in the DKIM signature to specify which public key should be used for verification. It allows you to have multiple DKIM keys within the same domain.

How does DKIM differ from DMARC?

DKIM verifies the authenticity & integrity of individual email messages by adding cryptographic signatures – while DMARC is a policy framework that provides domain owners with control over how their email domains are used and handles unauthenticated emails.

What are the benefits of DKIM?

DKIM enhances email security by reducing the risk of phishing & spoofing attacks, improves email deliverability, protects brand reputation, ensures regulatory compliance, and fosters trust between senders & recipients.

Why is DKIM essential for email security?

DKIM is essential for email security because it verifies sender identity, ensures message integrity, protects against email fraud, enhances deliverability rates, and helps organizations comply with regulatory requirements.