What is Email Encryption, and How Does it Work? | EasyDMARC

What is Email Encryption, and How Does it Work?

6 Min Read

Over the years, email has become the dominant collaboration tool used by businesses and organizations. However, emails aren’t secure by default. They’ve always been challenging in terms of security. They’re sent in plain text, after all. We’ve talked a lot about email authentication and validation a lot on our blog before. Plus, we offer tools to help you reach email security goals. However, we’ve not covered how to encrypt email until today.

So how do enterprises protect sensitive messages sent via email? Well, the answer is simple. Instead of sending out emails as unprotected plain text, entities encrypt their messages before sending. 

But what is email encryption, and how does it work? How can your organization leverage this technology? Find out more below.

Email Encryption Protocols and How They Work

What is the meaning of encrypted email? 

Email encryption is the process of encoding the content of the communication piece to prevent threat actors or unauthorized users from accessing your sensitive information. Encryption converts your email to a puzzle that only you and other authorized users can put back together. 

Today, there are two primary protocols for email encryption:

  • Encrypting emails in transit
  • End-to-end email encryption

Encrypting Emails in Transit

Email providers like Google and Microsoft use Transport Layer Security (TLS) to encrypt emails in transit. This makes it difficult for cyber attackers and unauthorized users to intercept your communication. 

Without TLS, cyber hackers can read emails moving from one node to another. These attacks are known as “man-in-the-middle,” where hackers hijack the message and pretend to be a legit party in the communication. Such threats can cause immense damage to a business, its reputation, and its professional relationships. 

TLS only protects emails that are in transit. So, cyber attackers can still compromise your email account through phishing. TLS alone doesn’t provide an adequate level of protection. That’s why many businesses and organizations consider enterprise email solutions that offer end-to-end email encryption. 

End-to-End Email Encryption

In end-to-end email encryption, only the Receiver can decode the Sender’s encrypted email. These emails are secure and unreadable by email servers, making it difficult for cyber actors to compromise. 

This encryption protocol uses a key to encode and decode the message. Each party has a public and private key. The Sender uses the public key to encode the email before sending, while the recipient uses the private key to decode it. 

Now, are you asking how to open an encrypted email? To do it, you need two types of encryption keys (alphanumeric strings). The Sender encodes the message using the Receiver’s public key. On the other end, the Receiver can open the message only if they have the private key of the Sender.

While end-to-end email encryption is the best option for data security, you can implement the algorithm in many ways. Most organizations deploy end-to-end encryption using Secure Multi-Purpose Internet Mail Extension (S/MIME) and Pretty Good Privacy (PGP).

Pretty Good Privacy (PGP)

PGP uses a hybrid approach. It’s an end-to-end encryption method that uses symmetric encryption, adding a layer of encryption on the public key itself. Here is how to encrypt an email using PGP:

  • The Sender wants to send an encrypted email to the Receiver
  • The Receiver generates public and private keys
  • The Receiver sends the public key to the Sender
  • The Sender encodes the email using the Receiver’s public key
  • The Receiver decodes the email with the Sender’s private key

Though Pretty Good Privacy is secure, it does come with some challenges. One significant obstacle is that public keys management is challenging for end-users. This is because they’re responsible for sending their public keys to people they want to communicate with. 

In the case of device loss, the PGP user has to exchange public keys with their contacts all over again.

Secure Multi-Purpose Internet Mail Extension (S/MIME)

Secure Multi-Purpose Internet Mail Extension is another end-to-end encryption protocol. Unlike PGP, S/MIME encrypts your email messages using digital certificates provided by the certificate authority (CA). Also, S/MIME uses a digital signature to find out the origin and authenticity of the message. 

One issue with S/MIME is that the protocol isn’t available for web-based email clients such as Google, and it’s inaccessible via a web portal. S/MIME also lets users store the public keys on a server, which cyber actors can compromise. 

Here’s Why Email Encryption is Important

 Email continues to be one of the predominant communication platforms among organizations and businesses. Understanding how to encrypt email is highly important, especially if you handle confidential information. Here are some reasons why. 

Safeguard Confidential Information

Organizations use electronic communication tools when discussing sensitive matters such as company secrets, personal information, contract papers, and other business assets. These documents and exchanges require confidentiality. Leaked information falling into the wrong hands can be damaging. 

Unencrypted emails can be read and altered. As a result, cyber actors can compromise your information and use it for nefarious purposes. To avoid leakage of confidential information, knowing how to encrypt your email is essential. 

Avoid Identity Theft

Suppose a hacker gets hold of your email password and username. In that case, they can read your messages and send fallacious communications on your behalf. This kind of identity theft often involves intercepted business or financial transactions. It’s best to avoid such threats by using email clients with built-in encryption. 

Email Repudiation

Hackers can easily forge regular emails, and you can never prove who sends them or their authenticity. This inability to show the true origin of a fake email poses severe risks for business communications. Email encryption helps prevent such scenarios with a process called non-repudiation. It offers proof of the integrity and origin of data.

What’s Our Say

Sensitive and private organization emails such as company secrets, passwords, and client information are popular targets for hackers. Confidential information is a gold mine for such imposters. At the same time, stolen identities and fraudulent emails represent countless opportunities for cybercriminals.  

Email security has become essential for small and large businesses to mitigate such risks. Organizations should invest in well-rounded and secure email encryption software. This will protect their internal data, private documents, and business communications.

Content Team Lead | EasyDMARC
Hasmik talks about DMARC, email security, and cyberawareness. She finds joy in turning tough technical concepts into approachable and fun articles in plain language.


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