--- title: "DKIM alone is not enough | DuoCircle" description: "https://media.mailhop.org/duocircle/images/2024/08/DKIM-alone-is-not-enough." image: "https://www.duocircle.com/images/og-default.png" canonical: "https://www.duocircle.com/blog/email-security/dkim-alone-is-not-enough/" --- Quick Answer DKIM only signs the message body and selected headers to prove content was not altered in transit. It does not verify the sender is authorized, it breaks when forwarders rewrite headers, and it provides no reporting. SPF authorizes which IPs can send for your domain, and DMARC tells receivers what to do on failure and sends back aggregate reports. You need all three. DKIM alone is not enough Your browser does not support the audio element. [ Download episode](https://media.mailhop.org/duocircle/images/2024/08/DKIM-alone-is-not-enough.mp3) Share [ ](https://www.linkedin.com/sharing/share-offsite/?url=undefined%2Fblog%2Femail-security%2Fdkim-alone-is-not-enough%2F "Share on LinkedIn") [ ](https://twitter.com/intent/tweet?text=DKIM%20alone%20is%20not%20enough&url=undefined%2Fblog%2Femail-security%2Fdkim-alone-is-not-enough%2F "Share on X/Twitter") [ ](https://www.facebook.com/sharer/sharer.php?u=undefined%2Fblog%2Femail-security%2Fdkim-alone-is-not-enough%2F "Share on Facebook") [ ](https://reddit.com/submit?url=undefined%2Fblog%2Femail-security%2Fdkim-alone-is-not-enough%2F&title=DKIM%20alone%20is%20not%20enough "Share on Reddit") [ ](mailto:?subject=DKIM%20alone%20is%20not%20enough&body=Check out this article: undefined%2Fblog%2Femail-security%2Fdkim-alone-is-not-enough%2F "Share via Email") ![DKIM (DomainKeys Identified Mail)](https://media.mailhop.org/duocircle/images/2024/08/spf-record-generator-8561.jpg) You might have heard that you do not necessarily need all three email authentication protocols, [SPF](/resources/what-is-spf) (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting, and Conformance) to create a foolproof defence strategy for your email ecosystem. But here’s a truth that these custodians of security do not tell you: achieving a 100% foolproof email security strategy is very challenging, if not impossible, and you need a **multi-layered approach** that covers all the bases and helps you stay ahead of these attacks. That being said, [DKIM](/resources/what-is-dkim) does allow you to keep an eye on the integrity of the contents of your outbound emails, but what about other aspects, like verifying the authenticity of the **sender or preventing unauthorized use** of your domain? It does not cater to them at all! So, with only the contents of the email as your focus, you cannot expect comprehensive security, especially when you’re leaving significant vulnerabilities unprotected. To give you a better idea of what we mean to say, let us take you through the specific limitations of DKIM and how SPF and [DMARC](/email/dmarc) come together to fill in those gaps. ## What is DKIM? _DKIM is an email authentication protocol that works to ensure that your outbound emails reach their destination as they are, without being intercepted by any attackers_. The real work begins as soon as you send an email from your domain. When you send an email, DKIM adds a [digital signature](https://www.techtarget.com/searchsecurity/definition/digital-signature) to the header. This signature consists of a private cryptographic key. When the **email reaches its destination**, what the receiving server does is, check this private key with the public one saved in your DNS. If the **two keys match** one another, the recipient’s server takes it as a sign that the message has not been tampered with during transit and allows it to enter the inbox. But if the private and the [public keys](https://www.investopedia.com/terms/p/public-key.asp) do not match, the message is then flagged as suspicious or fraudulent, leading to deliverability issues. [![cyber attackers](https://media.mailhop.org/duocircle/images/2024/08/spf-validator-5165.jpg)](https://media.mailhop.org/duocircle/images/2024/08/spf-validator-5165.jpg) ## Why is DKIM alone not enough for all-around email security? DKIM certainly plays a critical role in ensuring that your email contents are unaltered during transit, but is this assurance really helpful if the sender itself is a potential attacker? That is to say, despite the security that DKIM provides, there is still plenty of opportunity for [cyber attackers](https://www.cbsnews.com/video/new-cyberattack-targeting-iphone-apple-ids/) to slip through. Here are **some of the loopholes** that DKIM leaves: ### Limited protection Basically, DKIM only vouches for the integrity of the email content, which only offers partial protection. But when it comes to dodging [spoofing attacks](https://www.computerweekly.com/news/366546952/Rise-in-fraudsters-spoofing-the-websites-of-leading-UK-banks), where attackers fake a **trusted domain**, it does nothing! We say this because DKIM does not take into account the legitimacy of the email sender. The email could come from an address that is not authorized by the domain owner. ### Issues when forwarding an email DKIM faces a couple of issues, especially when an email undergoes certain changes while being forwarded. When an email is forwarded, it is modified with new headers, disclaimers, or signatures. The receiving server might not perceive these changes as harmless, and the difference in the public and [private keys](https://www.techopedia.com/definition/16135/private-key) can cause **DKIM verification** to fail. ### Complex setup Setting up DKIM is not easy, especially when there are so many **complexities involved**. If anything goes wrong, like an error in creating and managing cryptographic keys or configuring [DNS records](https://www.ibm.com/topics/dns-records), it could seriously mess up your [email deliverability](/a-guide-on-email-deliverability). ### Lack of reporting Unlike other **authentication protocols**, DKIM does not give you any information on how your emails are being handled by the servers on the receiving end. It doesn’t even give any feedback on whether the [DKIM signatures](https://medium.com/@rawatnimisha/dkim-signature-what-is-it-and-how-does-it-work-f4b8e4f18a4f) are failing or if your emails are being rejected. Without this information, you will have no idea about the potential issues, which makes it difficult to monitor the effectiveness of your email authentication and to troubleshoot when problems arise. ## How do SPF and DMARC fill the gaps left by DKIM? Since we know that DKIM alone won’t cut it for complete email protection, it is important to adopt strategies that patch vulnerabilities that DKIM leaves behind and add an **extra layer of protection**. This is where SPF and DMARC come in. The trio of SPF, DKIM, and DMARC work together to create a comprehensive [email authentication](/resources/email-authentication) framework. [![email security](https://media.mailhop.org/duocircle/images/2024/08/phishing-protection.jpg)](https://media.mailhop.org/duocircle/images/2024/08/phishing-protection.jpg) ### SPF (Sender Policy Framework) Unlike DKIM, SPF focuses on where exactly the email is coming from; it verifies if it was sent from an **authorized IP address**. This reduces the risk of attackers sending emails that claim to have come from your domain. _As important as it is for receiving servers to know that the email contains no malicious content, it is equally crucial for them to verify whether the sender on the other end of the communication can be trusted or not_. This is where SPF shines and builds on DKIM by adding a mechanism that prevents [domain spoofing](https://www.pcmag.com/news/nsa-warns-of-north-korean-hackers-spoofing-emails-from-legit-domains) and strengthens overall [email security](/). ### DMARC (Domain-based Message Authentication, Reporting, and Conformance) DMARC takes the best from both SPF and DKIM and builds on them by enabling [domain owners](https://www.darkreading.com/vulnerabilities-threats/sitting-ducks-attacks-create-hijacking-threat-for-domain-name-owners) to define how to treat emails that fail these checks. It lets you enforce any one of the three policies, none, quarantine, and reject, which determines what happens to emails that don’t pass authentication. Apart from this, the **reporting capabilities** of DMARC make the authentication protocol even more powerful. These comprehensive reports are very helpful in understanding how your domain is being used, whether for **legitimate communications** or malicious purposes. They enable you to monitor your [email traffic](https://emailanalytics.com/email-traffic/), identify potential abuse, and fine-tune your email security strategy to achieve better protection against threats. Do you still think DKIM alone will do the job of protecting your [email infrastructure](https://www.voilanorbert.com/blog/email-infrastructure/)? No, right? You need to protect your domain and create a sound [cybersecurity posture](/email-security/why-it-is-crucial-for-smes-to-have-a-robust-cybersecurity-posture/) by **implementing SPF and DMARC**, along with DKIM. To get started, [get a quote](/get-a-quote) from us today! ## Topics cyber securityDKIMDMARCemail securityspf ![Brad Slavin](https://media.mailhop.org/dmarcreport/images/team/brad-slavin.jpg) Brad Slavin General Manager General Manager at DuoCircle. Product strategy and commercial lead across the email security portfolio. ## Secure your email infrastructure Protect, authenticate, and deliver. Contact our team to find the right solution. [Contact Sales](/contact/) [Explore Products](/products/) ## Related Articles [ Email Security 12m DMARC, SPF, and DKIM in 2026: Why Email Authentication Is Now a Regulatory Requirement, Not Just a Best Practice Apr 29, 2026 ](/blog/dmarc-spf-dkim-2026-email-authentication-regulatory-requirement-best-practice/)[ Email Security 4m A practical guide on checking your email health Dec 26, 2025 ](/blog/email-security/a-practical-guide-on-checking-your-email-health/)[ Email Security 8m Best practices to make Privileged Account and Session Management a breeze Jan 7, 2025 ](/blog/email-security/best-practices-for-simplifying-privileged-account-and-session-management/)[ Email Security 5m BreakSPF attack- working, impact, and preventive measures Nov 26, 2024 ](/blog/email-security/breakspf-attack-working-impact-and-preventive-measures/) ```json {"@context":"https://schema.org","@type":"Organization","name":"DuoCircle LLC","url":"https://www.duocircle.com","logo":{"@type":"ImageObject","url":"https://www.duocircle.com/images/duocircle-logo.png"},"description":"DuoCircle is a portfolio of specialized email products covering protection, authentication, delivery, and routing. 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