How to Send Sensitive Information Online Safely

Every day, millions of people need to send sensitive information over the internet — Social Security numbers, bank details, medical information, legal documents, passwords, and private notes. The problem is that most common communication channels (email, SMS, chat) were not designed to keep this data safe.

Here's a practical guide to sending sensitive information online without putting yourself or others at risk.

Why Common Methods Are Unsafe

Before looking at solutions, it's important to understand why the tools most people use are problematic:

• Email — Emails are typically transmitted without encryption between mail servers. They're stored in plain text on servers, backed up multiple times, and retained for years. Your "private" email passes through and is stored on systems you don't control
• SMS and text messages — Vulnerable to interception, SIM swapping attacks, and stored in carrier logs. Not encrypted end-to-end
• Slack, Teams, and workplace chat — All messages are stored on company servers, searchable by administrators, and often retained for compliance. A password shared in Slack today could be found in a data export years from now
• Social media DMs — Facebook Messenger, Instagram, and Twitter DMs are stored on company servers and can be accessed by the platform

Safe Methods for Sending Sensitive Information

1. Self-Destructing Encrypted Links (Best for Text)

For sharing passwords, account numbers, PINs, or any text-based sensitive data, a self-destructing encrypted link is the simplest and most secure option. Tools like Authly Send encrypt your data in the browser, generate a one-time link, and permanently delete the content after it's viewed.

This is ideal because it requires no setup from the recipient — they just click a link. The sensitive data doesn't persist in any inbox or chat history.

2. End-to-End Encrypted Messaging (Best for Conversations)

For ongoing communication about sensitive topics, use an end-to-end encrypted messaging app like Signal. Messages are encrypted on your device and can only be decrypted by the recipient's device. Enable disappearing messages for an extra layer of protection.

3. Encrypted File Sharing (Best for Documents)

For sensitive documents (tax returns, medical records, legal files), use an encrypted file sharing service or password-protect the file before sending. You can also encrypt a ZIP archive with a strong password and share the password via a separate channel (like a self-destructing link).

4. Secure Client Portals (Best for Business)

Businesses that regularly exchange sensitive data with clients (accountants, lawyers, healthcare providers) should use dedicated secure portals with authentication and audit trails.

A Step-by-Step Guide to Sending Sensitive Info Safely

1. Evaluate what you're sending — Is it a password (use a one-time link), a document (encrypt it), or an ongoing conversation (use Signal)?
2. Choose the right tool — Match the tool to the type of data and your recipient's technical ability
3. Encrypt before sending — Ensure the data is encrypted before it leaves your device, not just "in transit"
4. Use a separate channel for access keys — If you're sharing an encrypted file, send the password through a different channel than the file itself
5. Set an expiration — Whether it's a one-time link or a shared document, set it to expire after a reasonable time
6. Confirm receipt — Verify that the recipient received the information, then ensure the sharing mechanism is destroyed

Common Mistakes to Avoid

• Sending everything in one email — An email with "Here's the login: user@example.com / MyP@ssword123" is a gift to any attacker who gains access to that mailbox
• Using "secure" email without verifying — Many email providers claim security but don't offer end-to-end encryption. Encryption "in transit" (TLS) only protects the data while it's moving between servers
• Trusting the "delete" button — Deleting a message from your end doesn't delete it from backups, the recipient's device, or server logs
• Sending sensitive data to the wrong person — Auto-complete in email clients is a leading cause of data leaks. Double-check the recipient before hitting send

The Simplest Secure Option

For most people, the easiest way to send sensitive information online is a zero-knowledge, self-destructing link. Authly Send lets you paste any sensitive text, encrypts it in your browser with AES-256 encryption, and generates a link that self-destructs after one view. No account needed, nothing stored permanently — just secure sharing in seconds.