Start with the information and the recipient
Choose secure messaging by deciding who should read the information, how they will receive it, and what should happen to the copies afterward. An encrypted connection protects a particular part of that journey. Device access, recipient identity and storage choices complete the picture.
Before sending, identify the information owner and any workplace rules. Confirm that the recipient needs the complete file; a short answer or a redacted extract may meet the task with less exposure. For work involving regulated records, use the organization’s approved channel and retention process.
Ask the recipient what they can actually open. A technically strong method fails in practice if it leads someone to upload the file to an unapproved converter or forward it to a personal account. Agree on the channel using a contact route you already trust.
| Task | Useful approach | Check before sending |
|---|---|---|
| Private conversation | An approved end-to-end encrypted messenger | The actual participants, linked devices and backup settings. |
| Business email | An approved encrypted-email workflow, such as supported OpenPGP or S/MIME | Recipient keys/certificates, compatible clients and the handling of replies and attachments. |
| Document collaboration | A controlled sharing service with named recipients | View/edit permissions, sign-in requirements, access review and download behavior. |
| Public announcement | Ordinary approved publishing or email | That the content really is intended for public distribution. |
The OpenPGP specification, RFC 9580 describes an encrypted-message format. A product implementing it still needs sound key distribution, usable software and a recovery plan. Evaluate the complete workflow.
Verify the contact before relying on the channel
A familiar display name or profile picture is easy to mistake for proof of identity. For a new contact or an unexpected request, confirm the person through an established phone number, an in-person exchange or a separately trusted organizational directory. Verify changed payment instructions through the organization’s usual approval process.
Signal provides a concrete example. Its safety-number instructions explain how to open a one-to-one chat’s contact settings and view the safety number. Compare it with the known person, ideally by scanning their displayed QR code in person, or by comparing through another trusted channel. Matching numbers establish the cryptographic relationship you compared; knowing who is on the other end requires that trusted introduction.
Mark a checked number as verified if appropriate. If it changes unexpectedly, pause sensitive messages and ask the contact through the established route. A phone replacement can explain a change, but the change alone does not identify its cause. Review group membership separately: a one-to-one verification does not approve every member of a group.
Follow the information after delivery
End-to-end encryption places decryption at the endpoints. Anyone with legitimate access to an unlocked endpoint may be able to read, photograph or copy a message. Review screen previews, shared computers and linked devices. A disappearing-message timer helps manage history; it cannot recall a screenshot or an independent copy.
Backups deserve their own check. Signal Secure Backups are optional and use end-to-end encryption with a recovery key. Store that key where you can retrieve it independently of a lost phone. Check the current media coverage and exclusions before assuming every attachment is recoverable.
For collaboration services, distinguish a named-person invitation from a link anyone can use. Microsoft’s SharePoint external-sharing overview explains how organization and site settings affect external sharing, including unauthenticated links. Ask the administrator which settings apply to your site. Revoking service access controls future access through that service; treat previously downloaded copies as a separate retention question.
Work through a sensitive-file handoff
Rehearse a new channel with harmless sample content. Confirm that the intended person can open it, that an uninvited test account cannot, and that access removal behaves as expected. If a real file goes to the wrong person, revoke access where supported, contact the information owner and follow the incident process promptly. Preserve relevant records while the owner decides what notification or recovery is needed.