Most of our communication shifted from analog to digital a long time ago. Letters became emails, phone calls became texts and video calls. With analog, privacy was mostly a given. Few people were going to steam open a letter or wiretap a phone line. The internet changed that. Digital communications can be intercepted at scale if they’re not properly protected.

Not everything needs to be locked down. Most of us prefer privacy in general, but a leaked dinner plan is usually just mildly embarrassing. The real concern is the stuff that could actually do damage if it ended up in the wrong hands: passwords, credit card numbers, bank account details, tax documents, retirement information, health records. When you need to share something like that, how do you do it safely?

Data at Rest and in Transit

Before getting into specific solutions, it helps to understand two different moments when your information is vulnerable:

In transit: This is data moving between systems. To protect it from being intercepted, you want encrypted communication channels:

• Between your app and a server: Nearly all internet-enabled apps and web browsers use SSL/TLS encryption. A lock icon in your browser’s address bar, or “https” at the start of a URL, means the connection is encrypted.
• End-to-end encryption: A step above that is end-to-end encryption, which means even the service provider can’t read your messages. iMessage (blue-bubble conversations), WhatsApp, and Signal all offer this (though WhatsApp archives are readable by other Meta apps). SMS is not encrypted at all, and RCS only supports encryption with the latest Apple and Google updates plus carrier support. Both SMS and RCS show up as green-bubble conversations.

At rest: This is data sitting somewhere: on your computer, on a mail server, or in the cloud. Two approaches help here:

• Per-file encryption: Encrypt the file before sending it so that even if someone gets their hands on it, they can’t open it without a password. Send the password through a completely separate channel, for example, share an encrypted file via email but send the password via Messages.
• Time- or access-expiring links: Send a link that expires after a set period or a limited number of views. This shrinks the window during which a breach could happen.

Choosing the Right Approach

The best method depends on four things:

• Your audience: How tech-savvy is the person on the receiving end? iMessage is easy and secure but only works for Apple users. Email reaches everyone but offers less protection. A password-protected PDF is probably easier for less technical users than an encrypted disk image.
• Content type: Sharing a password is different from sharing a document, which is different from sharing a collection of files.
• Sensitivity: How bad would it be if this got out? There’s a big difference between the password to a club forum and the login to your retirement account.
• Persistence: Does your recipient need to glance at it once, or keep a copy permanently?

Eight Secure Sharing Methods

With that context in mind, here are eight practical ways to share sensitive information securely:

1. Use a secure portal when available: Doctors, lawyers, accountants, and other professionals who handle sensitive information regularly often use secure client portals or services like DocuSign for sharing documents and messages. If they’ve provided one, use it. It’s usually the safest and simplest option.
2. iMessage, Signal, or WhatsApp: For quick, sensitive exchanges, end-to-end encrypted messaging works well. These are especially useful when you want to split information across channels: send a login URL and username via email, then the password separately via Messages.
3. Self-destructing links: Services like 1ty.me and One-Time Secret generate encrypted links that contain a piece of text. Once the recipient views it, the data is deleted and the link stops working. If they tell you the link was already used, you know something went wrong. One heads up: some email systems automatically scan links, which can trigger early deletion.
   
4. Password manager sharing: 1Password, Bitwarden, and some other password managers offer built-in secure sharing features. You can create links with expiration dates, limit access to specific email addresses, or set links to self-destruct after a single view. Apple’s Passwords app doesn’t currently offer this.
   
5. Password-protected PDF: For documents that might need to be printed or kept on file, a password-protected PDF is a solid option. From almost any app, go to File > Print, click the PDF menu at the bottom, and choose Save As PDF. In the save dialog, click Security Options, check “Require password to open document,” and set a strong password. Share the file however works best, but always send the password through a separate channel, ideally via an expiring link.
   
6. Password-protected disk image: For Mac users who need to share files that don’t convert easily to PDF, or a whole folder of files, a password-protected disk image is the way to go. In Disk Utility, go to File > New Image > Image from Folder, choose an encryption level (256-bit for anything sensitive), and set a strong password. Share the password separately, ideally via an expiring link.
   
7. Password-protected Zip archive: This serves the same purpose as a disk image and tends to be easier for Windows users to open. Apps like Keka and BetterZip can create them. For a quick Terminal approach, type zip -er ~/Desktop/filename.zip (with a space at the end), drag in the files you want to compress, press Return, and enter your password when prompted.
8. Time-expiring cloud storage links: Some cloud storage services let you set links that expire after a specified time. Dropbox Professional supports this, so you can share a file knowing the link will become useless if it ends up somewhere it shouldn’t.
   

There’s no single right answer here. The best approach depends on what you’re sharing, who you’re sharing it with, and how long they need access to it. When in doubt, err on the side of more protection rather than less.

(Featured image by iStock.com/metamorworks)