What are the best ways to encrypt files for emails?

If you’re wondering the best way to encrypt files for emails, you’re in the right place.

We’re going to go through the basics of encryption for emails, so you can send secure messages exclusively to your intended recipients and keep all relevant data out of the hands of hackers (or third parties).

While some email clients, like Protonmail or Tutanota, already encrypt all their emails by default, not all clients work this way.

Read on to find out how to encrypt messages no matter how you send your messages.

How to encrypt an email attachment

When it comes to types of email encryption, the quickest option you can choose is to use digital signature software.

This encryption software is designed specifically to only show your email’s content (including attachments) to your chosen recipients.

Some of the other strategies you can use to approach the problem of how to encrypt a file for email are detailed below:


Using S/MIME (Secure/Multipurpose Internet Mail Extensions) is a popular strategy for encrypting emails.

It works by encrypting the content using public key cryptography, then allowing recipients to use their private keys to “unlock” the encrypted files and email messages.

To make S/MIME encryption work, both the sender and their recipients need to have S/MIME certificates installed on their chosen email clients.

They’ll then be able to send secure emails.


Pretty Good Privacy, or PGP for short, doesn’t rely on senders sharing private keys for them to exchange secure files.

This makes it a better solution for sharing files with people you may not know well, or even have never met face-to-face.

However, with PGP, both the sender and their recipients have to make sure their security settings are compatible.

Otherwise, this can lead to technical issues.

Today, most people use openPGP, the open-source version of PGP.

Symmetric encryption

Lastly, this type of encryption essentially involves putting your attachments into password-protected zipped folders.

That stops outsiders from accessing them, unless they’ve also got your chosen encryption keys to hand.

Symmetric encryption is generally more basic than other solutions.

However, it still helps you take direct control of your security permissions, making it useful.

Are email attachments secure?

Cybersecurity is no joke.

You’ve got to protect yourself and others against data breaches and other threats when you send emails, which is why secure document sending is so important.

However, not every email attachment you receive is always going to be safe to open, especially if it’s coming from an unknown sender.

In that case, even a seemingly well-intentioned email message can pose a risk, as an attachment might actually be threatware in disguise.

How to encrypt email in Outlook

It’s very easy to send encrypted attachments (and text!) using Outlook.

All you have to do is write the email, click Options, then click Encrypt (the option marked with the lock icon). 

You can also adjust your encryption settings, including your chosen level of encryption, from the same place.

Please note that this email security strategy also works on Microsoft Office 365, so you can use it whether you’re an Outlook or Microsoft customer.

How to encrypt email in Gmail

If you’ve got a free email account with Gmail, you can use Confidential Mode by clicking on the lock icon on the bottom right of the screen, after you’ve hit Compose.

This works on both Mac and Windows devices.

Confidential Mode lets you send encrypted messages that expire after an amount of time — set by you.

It’s useful for plain text emails and ones with attachments alike.

Paid Gmail accounts can also use this, though they’ve got access to S/MIME encryption, too.

How to encrypt email in Yahoo Mail

For users of this email service, end-to-end encryption isn’t included by default.

You’ll need to use a browser plugin, because Yahoo discontinued their first-party encryption plugin.

Fortunately, popular browsers like Chrome and Firefox offer plenty of encryption tools, apps, and plugins, and often for free.

How to encrypt email on Mac

Users of Apple devices can send encrypted emails without turning to external email providers.

All they need to do is download an encryption certificate, then use the mail app on their device. Mail will then all be encrypted.

The type of certificate you’re looking for is an S/MIME.

This lets you adjust the settings on your device so your digital ID is set to always send emails securely.

How to encrypt email on iPhone

iOS users will also need to use S/MIME encryption certificates.

You can easily get these from a certificate authority.

Once you’ve got your certificate, you’ll want to choose to encrypt by default.

This option can be found under Settings > Mail > Accounts > Account > Advanced > Encrypt by Default.

How to encrypt email on Android

There’s no specific option that’s unique to Android, but that doesn’t have to be a bad thing.

Android users can use the PGP and/or S/MIME method to protect their outgoing (and incoming) communications.

These are well-known and established protocols, meaning they’re updated regularly and protect properly against outside threats and unwanted eyes on your content.

Secure your documents with email encryption

Now that you know how to encrypt email attachments, you’ll be able to keep sensitive information under wraps. That’s vital in today’s age of increasingly advanced cybercrime.

You can always improve your cybersecurity by adding more safety measures, such as using a VPN and/or introducing two-factor authentication.

These make it even harder for scammers and fraudsters to perform their craft on you.

Or you could trust all your secure document workflows to PandaDoc.

Our security is a top priority and we ensure we’re always up-to-date with industry standards and compliance. Start a 14-day trial to see what else we can help you with.