How to Encrypt Email and Send Secure Messages

Article Update on September 21, 2026

Sending sensitive information like a bank account number or password over email leaves you exposed if that message is intercepted. Encrypting your email closes that gap: it scrambles the content so that even if someone gains access to it in transit, they can't read it. The two main standards for this are S/MIME and PGP/MIME, and most major email platforms support one or both.

Why Email Encryption Matters

Email has been a weak point in personal and business security for years. In 2013, hackers compromised all three billion Yahoo accounts that existed at the time, a breach that wasn't publicly disclosed until 2016 and remains the largest confirmed data breach on record. Malicious email activity hasn't slowed down since: an estimated 1.2% of all emails sent daily are malicious, amounting to roughly 3.4 billion phishing emails a day. 

The good news is that protecting yourself doesn't require much technical know-how, just the right settings turned on.

What Is Encrypted Email and What Are the Benefits

There are two primary protocols used to encrypt email:

S/MIME (Secure/Multipurpose Internet Mail Extensions)

S/MIME lets you send encrypted, digitally signed emails. The digital signature confirms to the recipient that the message they received is exactly what the sender sent, and that it's actually from the sender it claims to be from, not someone spoofing their identity.

S/MIME provides authentication, message integrity, and digital signatures, working together to protect both sender and recipient. It also pairs with Transport Layer Security (TLS), which encrypts the connection between mail servers. Note that S/MIME protects a message in transit; it's a separate layer from device-level encryption tools like BitLocker® (Windows) or FileVault (Mac), which protect data stored on a hard drive.

PGP/MIME (Pretty Good Privacy/Multipurpose Internet Mail Extensions)

PGP/MIME also encrypts and signs an email and its attachments, with more flexibility over the encryption strength, though it requires a third-party encryption tool. If an email encrypted this way is intercepted, its contents stay unreadable. To read the message, the recipient has to download the full message, including all attachments, since everything is encrypted together.

Benefits of Encrypted Email

• Safeguards sensitive data. If you're sending something like a Social Security number over email, encryption makes it much harder for a hacker to intercept and read.
• Cost-effective. Encryption built into your existing email server means you don't need to buy separate security hardware.
• Saves time. Rather than juggling several tools to secure a connection, encryption handles most of the work automatically.
• Supports regulatory compliance. In fields like healthcare, failing to secure sensitive data can put you in violation of laws like HIPAA. Encryption helps you stay compliant.
• Protects against malware. A digital signature helps confirm an attachment is genuinely from the sender, reducing the risk of opening a malicious file disguised as a legitimate one.

How to Encrypt Email in Gmail™

What's available to you depends on your account type.

Personal Gmail accounts don't support S/MIME. For personal accounts, Google offers Confidential Mode instead, which lets you set an expiration date, block forwarding or downloading, and require a passcode to open a message. It's worth knowing that Confidential Mode restricts what a recipient can do with a message; it is not true end-to-end encryption. To actually encrypt a personal Gmail message, you'll need a third-party browser extension (see the section below). 

Google Workspace accounts can use hosted S/MIME if an administrator has enabled it:

1. Begin composing a message.
2. Add a recipient in the "To" field.
3. Click the lock icon next to the recipient's address.
4. Click "View details" to see or change the encryption level.

The lock icon tells you the encryption level in use:

• Green: The message is protected by S/MIME encryption, readable only with the recipient's private key.
• Gray: The message is protected by standard TLS encryption, which works as long as both sender and recipient support TLS.
• Red: No encryption is applied.

How to Encrypt Email in Outlook®

S/MIME encryption: Before you start, you'll need a signing certificate added to your computer's keychain.

1. Go to File > Options > Trust Center > Trust Center Settings.
2. Select Email Security.
3. Under Encrypted email, select Settings.
4. Under Certificates and Algorithms, select Choose, then choose your S/MIME certificate.
5. Select OK, then write and send your email as usual.

Microsoft 365® message encryption: In an email, select Options, then Encrypt, and choose the restriction level you want, such as Encrypt-Only or Do Not Forward.

To encrypt all outgoing messages by default, confirm your recipients have your digital ID to decrypt your messages first, then:

1. Go to File > Options > Trust Center > Trust Center Settings.
2. Under Email Security, go to Encrypted email and select "Encrypt contents and attachments for outgoing messages."
3. Adjust any additional settings, such as which certificate to use, from the same screen.

How to Encrypt Email on iOS®

Before you start, confirm:

• Your iPhone or iPad is running a current version of iOS.
• Your email account is set up and working.
• The email address you want to encrypt matches the one configured on your device.

To set up S/MIME: install the certificate file from your administrator or certificate authority, then go to Settings > Mail > Accounts, select your account, and open Advanced Settings. From there, turn on S/MIME and choose whether to sign, encrypt, or both. Once it's active, a blue lock icon means a message can be encrypted; a red lock means the recipient needs to turn on S/MIME on their end first.

Email Providers That Require Third-Party Encryption Tools

Not every provider has encryption built in. Yahoo Mail supports TLS but needs a third-party tool for stronger encryption, and Android's native mail app requires additional setup to send encrypted messages too.

A few current options worth knowing:

• Proton Mail: Offers free and paid plans with built-in PGP encryption, available on Android and Apple devices.
• Virtru: Adds end-to-end encryption on top of Microsoft 365 or Google Workspace without requiring you to switch providers.
• Mailvelope: A free browser extension that adds PGP encryption to Gmail and other webmail providers, no plan upgrade required.

Make Encryption Part of Your Everyday Email Habits

Data breaches aren't slowing down, which makes encrypting sensitive messages one of the simplest habits you can build into your routine. Once it's set up, most of it runs in the background. For a broader look at protecting your accounts and data, see 10 Simple Steps to Protect Your Privacy Online, and for devices with built-in protection against the phishing links that often lead to compromised accounts, browse HP laptops with built-in threat protection.