Messages you send with most email providers aren’t secure, but there are ways to send sensitive information by email.
Most email services were built for convenience, not confidentiality. Yet it remains a core communication tool in business.
But if you work in a regulated industry or handle personal, financial, or legal data, sharing sensitive information — like customer bank details, Social Security numbers (SSNs), and confidential client billing information — sending them over email is inherently risky.
Interception, unauthorized access, and accidental exposure are likely threats. But when trust is part of your business model, how you handle sensitive information matters just as much as what you deliver.
We’re here to help. Keep reading if you’re a business leader looking to understand:
- What qualifies as sensitive information
- Which types of data require additional protection when shared over email
- Why standard email isn’t a safe channel for sensitive information
- 4 ways to send sensitive information by email
- How encrypted email can be used to send sensitive data securely
What is sensitive information?
Sensitive information is any data that could make an individual or business vulnerable to fraud, identity theft, financial loss, or legal exposure.
This data is considered sensitive because, if exposed, it can be exploited to impersonate individuals, access accounts, or commit financial fraud.
In practice, businesses routinely share sensitive material. They could be financial reports, contracts, employee records, or customer data.
Sending this information over standard email exposes organizations to compliance failures, fines, and reputational damage.
Which types of data require additional protection when shared over email?
Most individuals and businesses handle personal and confidential business information daily — often without realizing how exposed it can be in standard email workflows. Data that must be protected for privacy or security reasons is commonly grouped into three categories, based on who the data belongs to and the impact of its exposure:
Personal information
What it includes:
• SSNs, bank statements, job applications, CVs, contact details, travel documents.
• Highly sensitive data such as medical history, sexual orientation, religion, or political affiliations.
Why it matters:
• Identifies an individual and can be used for identity theft.
• Some attributes can lead to discrimination or harassment.
Confidential business information
What it includes:
• Trade secrets, financial data, product plans.
• Customer and client data, employee records.
Why it matters:
• Breaches can cause lawsuits, fines, and reputational damage.
• Required to be protected under laws like GDPR.
Government-classified information
What it includes:
• Data protected for national security or foreign relations.
• Includes classification levels (Confidential, Secret, Top Secret) and SCI.
Why it matters:
• Mishandling can endanger lives and harm diplomatic relations.
• Severe legal penalties apply.
Why isn’t standard email a safe channel for sensitive information?
Standard email isn’t a safe channel for sensitive information because it was never designed to deliver information, not protect the data inside them.
What about email providers that advertise encryption? Most providers rely on basic transport encryption, such as TLS, which only protects messages while they are in transit.
Once an email reaches the provider’s servers, it is typically stored in a form that the provider can access, making your sensitive information readable outside the sender’s and recipient’s control.
The underlying access controls often don’t match the sensitivity of the information being shared.
Even when more advanced security options are available, they can be complex to configure and manage. Businesses may need to take on manual key management, custom policies, or technical expertise that they don’t have the capacity for.
This gap — between the sensitivity of the data and the security most email systems actually enforce — often introduces compliance risks for businesses that regularly handle sensitive information.
So, is it possible to share information safely through email? Yes, but only with the right safeguards in place.
1. Use end-to-end encrypted email
The most private and secure way to send sensitive information by email is to use end-to-end encryption.
End-to-end encrypted email ensures that messages are encrypted on the sender’s device and can only be decrypted by the intended recipient. This means the contents of the email remain unreadable to anyone else — including the email service provider, intermediaries, advertisers, or third parties.
Unlike basic transport encryption, end-to-end encryption protects messages both in transit and at rest, significantly reducing the risk of interception, unauthorized access, or exposure in the event of a breach.
Secure personal use
Encrypted email allows individuals to safely share highly sensitive personal information — such as Social Security numbers, bank details, or identity documents — without exposing that data to unnecessary risk.
Secure business use
For businesses, encrypted email provides a way to send confidential information — including financial reports, employee records, contracts, and client data — while supporting privacy and data protection requirements. By limiting access to message contents, encryption helps organizations reduce compliance risk when sensitive data must be shared electronically.
Learn more about end-to-end encryption
2. Password-protect your business emails
To send sensitive information to someone who isn’t using an encrypted email service, use a password-protected email.
Instead of delivering the message contents directly to the recipient’s inbox, password-protected emails require the recipient to enter a password before they can read the message.
This adds a layer of protection if an email is intercepted, misdelivered, or accessed through a compromised account.
How password-protected emails work
While the exact steps vary by provider, the general process looks like this:
- Compose your email as usual.
- Enable password protection or secure message sharing before sending.
- Share the password with the recipient through a separate, secure channel (such as a phone call or encrypted messaging app).
Use password protection only when stronger encryption isn’t available. Always share the password through a separate, secure channel. Never send the password in the same email as the message — doing so cancels out the added security.
Learn more about password-protecting emails
3. Password-protect your attachments
Password-protecting attachments is often sufficient when the email body itself contains no sensitive information and the risk lies primarily in the file — such as a standalone report, form, or document.
Protecting the file itself adds an important layer of security. When sending a sensitive document, apply password protection before attaching it to your email. Most common file types — including Microsoft Word, Excel, PowerPoint, and PDFs — support built-in password protection.
Create your file, set a strong password or passphrase, and then attach it to your email.
Note: Encryption strength varies by file type, and recipients must have compatible software to open protected files. If the email message itself includes sensitive details or contextual information, protecting only the attachment may not be enough — in those cases, securing the entire message is the safer option.
Learn how to send documents securely via email
4. Use encrypted cloud storage
Email services often limit attachment sizes, making it difficult to send large files or multiple documents at once.
In these cases, using a secure cloud storage service with encrypted sharing links is a safer and more practical alternative. Instead of attaching files directly to an email, you upload them to a secure storage space and share a link with the recipient.
This approach works well for sharing personal files, large project folders, client deliverables, or technical documents — without exposing the files themselves in an inbox.
How secure link sharing works
While exact steps vary by provider, the general process is:
- Upload your files to a secure cloud storage service.
- Generate a private or encrypted sharing link for the selected files or folders.
- Add the link to your email and send it to the recipient.
- The recipient uses the link to securely download or access the files.
Secure link sharing is most effective when paired with additional access controls, such as password protection, expiration dates, or download restrictions. These controls help limit who can access the files — and for how long — reducing the risk of unauthorized access if the link is forwarded or exposed.
When combined with strong encryption, secure file sharing links allow teams to collaborate and exchange sensitive information without relying on email attachments at all.
You can protect your file-sharing link with a password or set an expiration date after which the link will be disabled.
Learn more about secure file sharing
Easiest way to securely email sensitive data
Even with Slack, secure file-sharing tools, and client portals, email remains an unavoidable part of daily work. If you handle personal, financial, or confidential information, the risk isn’t that you use email — it’s how you use it.
With the right safeguards, you can continue to use email without sacrificing confidentiality or trust. But these measures are acceptable stopgaps, not a system that’s secure by default.
Instead of relying on workarounds, manual decisions, or perfect user behavior, end-to-end encrypted email protects messages automatically, every time they’re sent.
Proton Mail is designed around this principle. Messages are encrypted by default, access to contents is limited strictly to the sender and recipient, and security doesn’t depend on sharing passwords, switching tools, or adding friction to everyday workflows.
If you’d like to support our vision, sign up for a paid plan. Together, we can build a better internet where privacy is the default.
