Why do we need to know how email encryption works? As a fun fact, billions of emails are sent around the world every day. However, only a small number of these emails are encrypted, leaving most open to interception.
So, there are lots of people who could be listening in on your emails as they travel from your inbox to their destination.
This is where email encryption comes in. It scrambles your messages so that only the person you’re sending them to can read them.
That’s why, let’s break down the fundamentals of email encryption here.
What is Email Encryption?
Email encryption is when you encode the contents of an email to keep it safe from people who shouldn’t have access to it.
This means only the person who’s meant to read the message can do so.
Encryption is used for both data in transit and at rest. Which makes it a really important tool for keeping sensitive communications confidential and secure.
There are a few different ways to encrypt emails, like Transport Layer Security (TLS) and End-to-End Encryption (E2EE), which are designed to keep your messages safe from being intercepted.
Why Encrypt Emails?
There are a few good reasons for encryption, and especially in industries that handle sensitive data.
The Symantec white paper, “Busting the Myth of Email Encryption Complexity,” says more than 75% of a company’s intellectual property, including financial records and personal information, is often exchanged via email.
If you don’t encrypt your data, it could be intercepted, which could lead to theft, espionage, or leaks.
Symantec’s white paper also shows how 294 billion emails are sent every day, but only a small fraction are encrypted, leaving the vast majority vulnerable.
The Australian Signals Directorate (ASD) “Guidelines for Email” show how unencrypted emails are easy targets for espionage, with threats from both state actors and private hackers becoming more common.
In 2020, the Australian Signals Directorate (ASD) reported a rise in cyberattacks targeting government and private sector communications.
There are also legal frameworks like Australia’s Privacy Act 1988 that impose strict penalties on organizations that don’t protect personal information.
This shows how important encryption is for complying with data protection laws.
If you encrypt your emails, you can reduce any risks by making sure that only the right people can access the information.
This not only protects your intellectual property but also keeps your reputation and finances safe from the knock-on effects of a data breach.
Types of Information Protected by Email Encryption
Email encryption isn’t just about protecting the obvious, like financial transactions or classified government communications.
Symantec’s white paper shows there’s a lot of a company’s intellectual property – ideas, strategies, and trade secrets – in emails, presentations, and spreadsheets which seem pretty mundane.
Theft of this kind can have a big impact on a company, potentially damaging its competitive advantage.
It’s also a big deal to keep Personally Identifiable Information (PII) safe when you’re encrypting emails.
Medical records, financial details and even home addresses can be used to steal your identity, commit fraud or blackmail you.
The ADS email manual makes a big deal about the importance of protective markings on emails with sensitive data, which shows how strict the data protection rules are.
The manual also points out that we need to make sure we keep classified government information, trade secrets and financial data safe.
It shows us that there’s a lot of different types of information that we need to protect.
But, email encryption isn’t just about encrypting the body of your emails.
And don’t forget to protect your email attachments, which often contain important documents or images – they could be vulnerable to interception too.
What’s more, the paper ‘Usability of End-to-End Encryption in E-Mail Communication’ by Adrian Reuter et al., also points out that it’s important to protect not just the email content, but also the metadata.
Email Encryption Methods
Transport Layer Security (TLS)
Transport Layer Security, or TLS, is a protocol designed to create an encrypted connection between email servers.
It’s like sending your email through a secure tunnel, keeping it safe on its way between servers.
However, as the ADS manual points out, TLS is vulnerable to downgrade attacks, where malicious actors force a less secure connection.
To get around this, the manual suggests using Mail Transfer Agent Strict Transport Security (MTA-STS) to make sure emails are only transferred if there’s strong TLS encryption in place.
End-to-End Encryption (E2EE)
End-to-end encryption (E2EE) is another way to keep your emails safe.
It encrypts messages on the sender’s device and only decrypts them on the recipient’s device. This means that even the email service provider can’t access the plaintext content.
In their study, Reuters and their co-author look at the challenges users face with E2EE technologies like PGP, S/MIME, and pEp.
The study also shows how, despite the importance of E2EE, its adoption is slowed down by complex key management and setup procedures.
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Key Encryption Protocols
The key to email encryption is a set of protocols defining how messages are scrambled and unscrambled.
These protocols use complex mathematical algorithms to change plaintext into ciphertext, making it impossible for anyone without the right credentials to understand it.
Knowing how these protocols work is the best way to understand how email encryption works and the level of security it provides.
Pretty Good Privacy (PGP)
As Reuter et al., point out, Pretty Good Privacy (PGP) is a well-known protocol with strong end-to-end encryption.
It uses a mix of symmetric and asymmetric cryptography to keep email communications safe.
In a nutshell, PGP creates a unique key pair for each user, comprising a public key and a private key.
You can share your public key with others so they can encrypt messages that only you can decrypt.
While PGP is secure, it’s not that easy to use, especially for people who aren’t technically minded.
The study by Reuter et al. found some users often have trouble with key management and the setup process, which makes it harder for them to use it more widely.
S/MIME (Secure/Multipurpose Internet Mail Extensions)
S/MIME is another well-known protocol offering end-to-end encryption for email.
It uses digital certificates from trusted Certificate Authorities (CAs) to verify users and share encryption keys.
S/MIME is often built into popular email clients, which makes it easier for users.
However, as Reuter et al. have pointed out, getting and managing digital certificates can be a bit of a hassle, and the configuration process can be pretty complex, particularly on mobile devices.
OpenPGP
OpenPGP is an open-source standard based on PGP, offering similar functionality and security.
The idea is to make it easy for different email encryption systems to work together.
This protocol lets users chat securely, no matter what email client or software they’re using.
OpenPGP, like PGP, uses a web of trust model where users verify each other’s public keys, creating a decentralised network of trust.
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How Email Encryption Works: Step-by-Step Process
The email encryption process is based on some pretty complex cryptographic algorithms, but it can be broken down into a few simple steps.
So, the process starts with the sender writing their email as usual, putting the message in plain text, which is easy for humans to read.
This is when the email is most vulnerable, open to interception and unauthorised access.
Once the email is ready to go, the sender gets the encryption process started. The chosen encryption protocol, such as PGP, S/MIME, or OpenPGP, is then used.
The sender’s email software uses the recipient’s public key, which is a freely shareable cryptographic key, to encrypt the message.
This basically scrambles the plaintext into ciphertext, which is an unreadable jumble of characters.
The encrypted email is now sent across the internet in ciphertext. It might pass through a few different servers and networks on its way to the recipient.
Even if someone intercepts the email while it’s being sent, they won’t be able to read it unless they have the private key.
The ADS email guideline makes a big deal about keeping emails safe while they’re being sent between servers. It says that Transport Layer Security (TLS) is the way to go.
When the recipient gets the encrypted email, their email client or software uses their private key, which is a closely guarded secret, to decrypt the message.
This process does the opposite of encryption, turning the ciphertext back into plaintext so the recipient can read the email.
Can Encrypted Emails Be Hacked?
While email encryption is a great way to keep your messages safe, it’s important to remember there’s no such thing as a completely foolproof system.
It’s possible to hack encrypted emails, but the methods used are usually pretty complex and require a lot of resources.
Attacks could target weaknesses in the encryption protocols themselves, weak passwords used to protect private keys, or even social engineering tactics to trick users into revealing sensitive information.
To help you avoid these risks, we at Interscale offer a range of strong Email Security & Protection Services designed to keep your business safe.
Interscale’s platform has some pretty advanced features, like dynamic URL and attachment scanning, policy-based encryption, and a 10-year email archive for compliance.
These services are designed with Australian businesses in mind, and also we offer comprehensive protection for small and medium-sized enterprises.
So, when you’re good to go, feel free to take a look at our Interscale IT Email Security & Protection Service page.
We’ve got some real-life examples from businesses just like yours. They faced the same email challenges and came out stronger because we were there for them.
Or when you’re ready for a coffee and a croissant, let’s meet up. No hard sell, no pushy pitch. Let’s discuss your email issues and how we can help you tackle them.
In Closing
While technologies like PGP, S/MIME, and OpenPGP are great for keeping your data safe, managing encryption effectively can still be tricky.
That’s why we at Interscale offer reliable email security services to help you stay secure.
With Interscale as your partner, you can get to grips with how email encryption works in practice and keep your emails secure 24/7.
