Secure file sharing versus email attachments
Ordinary email creates readable copies across multiple systems. A browser-encrypted file link can reduce stored plaintext and limit retrieval, while still requiring trusted recipients and endpoints.
By Strumio Editorial Team · Published August 28, 2026 · Updated August 28, 2026
Reduce the file before choosing a delivery tool
Review whether the recipient needs the entire file. Remove hidden worksheets, tracked changes, comments, document properties, embedded objects, old revisions, location data, and unrelated records. Export a purpose-specific copy and scan it with trusted local security tooling. Data never included cannot be exposed by the handoff.
Choose a format the recipient can open safely and tell them the expected filename, type, and approximate size through a known channel. If a document contains active content, macros, or executable code, explain that explicitly. Do not disguise file types or assume encryption makes a malicious attachment safe.
Verify access and set a useful lifetime
Confirm the intended recipient through a contact method you already trust, especially when a request changes payment instructions, identity documents, source code, or customer data. Address autocomplete mistakes and forwarded threads are common causes of disclosure. Send business context separately from the complete access link.
Strumio encrypts an attachment in the sender's browser before upload and decrypts it in the recipient's browser. Choose the shortest realistic expiration. A SecretLink can support one-time delivery; a signed-in chat can support a standard encrypted attachment or a Dead Drop with a limited number of successful claims.
Choose between a SecretLink, chat attachment, and Dead Drop
Use a SecretLink for one focused handoff, optionally accompanied by message text and one encrypted reply. Use chat when participants need temporary discussion around the file. Use a standard chat attachment when it should remain available while the room is active, or Dead Drop when limiting successful claims is more important.
The final permitted Dead Drop claim locks later access and queues stored ciphertext for deletion. This controls future retrieval from Strumio, not copies already downloaded. A one-time SecretLink has the same fundamental boundary: the first successful viewer can save, copy, photograph, or redistribute decrypted content.
Protect links, passwords, devices, and downloads
The complete link includes fragment-held key material and must be treated as sensitive. If you add a password, send it through a different channel and do not use a weak shared phrase. Verify the displayed Strumio domain before entering a password or opening a file. QR codes containing complete links carry the same access capability.
Both endpoints matter. Malware, browser extensions, synchronized clipboards, screen recording, backups, and unmanaged downloads can expose plaintext. Recipients should open sensitive files on approved devices and store necessary copies in an access-controlled location, not a public downloads folder or broadly synchronized personal drive.
Compare retention with an ordinary email attachment
Email commonly leaves readable attachment copies in sent folders, recipient inboxes, provider systems, local clients, forwarding chains, and backups. A browser-encrypted Strumio link stores ciphertext and can limit later retrieval with expiration, one-time access, room ending, or a Dead Drop claim limit. That is useful for a focused transfer.
Neither method can retract a recipient's downloaded copy. Confirm receipt without asking for the file back, delete or end the Strumio item when delivery is complete, and revoke credentials embedded in the file. For ongoing collaboration or regulated retention, use a managed document system with individual accounts, versioning, policy, and audit controls.
Related guidance
When an encrypted delivery link is appropriate, Create a free Strumio account.