Do your emails actually reach their audience or simply end up in their spam folders, or even worse, don’t reach them at all? Yes, this is very much a possibility!

This happens for many reasons, and one of them is that the receiving servers do not consider your emails safe enough to be let in. What we mean to say is that the recipient’s servers might suspect that the incoming email is tampered with; perhaps it was altered by a cyberattacker along its way. This is where DKIM comes in.

DKIM or DomainKeys Identified Mail is an authentication protocol that digitally signs outgoing emails so that recipients can verify they truly came from your domain and haven’t been altered in transit. The key to an effective DKIM setup is the right key length! The length of these keys—commonly 1024-bit or 2048-bit—determines how strong the encryption is.

On the surface, it might seem like a trivial detail, but in reality, the selection of key length has a direct bearing on how secure our emails are and how much they are trusted by recipient mail servers.

What is a 2048-Bit DKIM Key?

A 2048-bit DKIM key gives your emails a much stronger layer of protection. The longer the key, the more difficult it is for someone to spoof your email or tamper with it. So, when you have a 2048-bit key, it’s much more difficult for a cyberattacker to break in or impersonate you. It makes your emails more likely to be trusted by recipients’ mail servers and actually end up in their inboxes rather than spam.

How do These Keys Work?

When you send an email, your mail server signs the message with a private DKIM key by adding a special digital signature to it. This signature is generated based on the email content and your domain. When the email arrives at the recipient’s mailbox, their mail server verifies your published public DKIM key in your DNS settings. It uses that to confirm the signature. If the signature matches, the server can be sure that the email is genuine and wasn’t modified along the way.

You might be wondering what the length of the key has to do with the matching of public and private keys. Well, the length of the key doesn’t really affect the basic process, but it does impact how difficult it would be for an attacker to crack that system. Since a 2048-bit is considerably longer and more complicated than a 1024-bit key, an attacker would have to try way more possible combinations to forge your signature, ultimately making it harder for them to spoof your emails.

What is a 1024-Bit DKIM Key?

1024-bit key provides a good level of security by authenticating your outgoing emails and preventing tampering or impersonation. Although it is not as long and complex as the 2048-bit key, it works in most situations.

That being said, since 1024-bit keys are shorter, they are becoming easier to crack with modern computing power. Moreover, cyberattackers are also getting smarter by the second, which means they’re constantly devising new techniques and strategies to break weaker encryption like the 1024-bit key.

This does not mean that the 1024-bit key is completely unsafe; you do get a basic level of protection, and it is supported by most systems. But to truly safeguard your email ecosystem, you need to go beyond basic protection.

Should You Stick to a 1024-Bit DKIM Key or Switch to 2048-Bit?

If you have implemented the 1024-bit key and are wondering if it is worth making a switch, this one’s for you!

1024-Bit DKIM Keys Still Work—For Now

As we established earlier, the 1024-bit key does offer a basic level of security and is widely used and supported by most email providers. In fact, in most cases, it will work just fine! So, if you’re using it right now, your emails will get delivered without a hitch. But when cyberattacks become all the more frequent and sophisticated, that’s when they will start to fall short.

But 1024-bit Keys are Becoming Easier to Break

As processing capacity grows and cyber attackers become more sophisticated, shorter keys such as 1024-bit are now relatively simple to break. That makes it increasingly dangerous to use them, particularly for companies that send large amounts of email or process sensitive information.

2048-Bit Keys Offer Stronger, Future-Proof Protection

A 2048-bit DKIM key is basically a more secure version of what you’re already working with. It’s longer, more difficult to crack, and provides significantly more protection against today’s cyberattacks. If you’re using a 1024-bit key, an attacker can leverage their technical prowess to eventually create a fake version of your email signature and launch grave attacks. But with a 2048-bit key, the chances of this happening are significantly lower!

It Helps Mail Servers Trust Your Emails

As you know, email providers like Gmail and Outlook don’t just deliver every message they receive. First, they scrutinize them and then decide whether they can trust them. And among the things they consider is your DKIM key. If you’re using a 2048-bit key, it tells them you’re serious about security, which makes it more likely that your emails are delivered to the recipient’s inboxes rather than spam.

The Switch to 2048-Bit is Not That Hard

Switching to a 2048-bit key might seem like a daunting task, but it isn’t complicated and totally worth it! All you have to do is generate a new key in PowerShell (if you use Microsoft 365) or Google Workspace and update your DNS record. Once it’s done, you don’t have to worry about it anytime soon.

Like what you just read?

Hi, I’m Daksh Kaur, a freelance writer. I’m here to simplify cybersecurity for your clients by breaking down complex concepts into simple ones so that they can understand the risks and take proactive steps to make digital security a priority.

Email me at daksh@turtlewords.com, and let’s discuss how we can work together to create insightful and engaging content that converts.