How Dead Drop file sharing works

Create a signed-in room and choose Dead Drop

Dead Drop attachments are available in signed-in Strumio chat rather than the narrower account-free temporary room. The sender selects the Dead Drop option and an access limit for the encrypted attachment. Use it when limiting successful claims matters more than keeping a standard attachment available for the room's full lifetime.

Choose a limit that fits the real recipients and expected retries. A limit counts successful claims, not verified human identities, and multiple allowed claims may be used by the same capability holder. Confirm room participants outside the chat when identity matters and protect the complete fragment-bearing invitation.

Encrypt the attachment before upload

The sender's browser encrypts the file with AES-256-GCM before upload. Strumio stores encrypted bytes and the operational records needed to enforce room access and claim state. An authorized recipient's browser retrieves and decrypts a permitted claim for preview or download.

Browser encryption keeps file plaintext out of the stored Strumio object, but sender and recipient endpoints still see plaintext. Malware, extensions, screen recording, clipboard tools, and intentional copying can expose it. Explain the expected filename, type, and size and use trusted current devices.

Understand the atomic final claim

Each successful claim advances the attachment toward its configured limit. The final permitted claim atomically locks the Dead Drop against later access and queues its stored ciphertext for deletion. Atomic handling prevents two later requests from both treating the same final slot as available.

Locking and queued deletion apply to the stored Strumio attachment. They do not retract a file that an allowed claimant already downloaded, copied, cached, photographed, or placed into another system. Do not describe a Dead Drop as self-destructing on recipient devices.

Compare Dead Drop with other delivery choices

A standard encrypted chat attachment is appropriate when the file should remain available while the room and attachment are active. A Dead Drop adds claim scarcity. A one-time SecretLink is often simpler for one focused recipient handoff, while chat is useful when participants need discussion around the file.

Account-free rooms support encrypted text only, so attachments and Dead Drops require a signed-in room. Room expiration and the creator's End action also limit later room access, but neither changes the fact that a successful recipient can retain plaintext outside Strumio.

Prepare the file and respond after a claim

Remove unnecessary fields, metadata, revisions, and embedded content before sharing. Scan unexpected or active file formats with appropriate local controls. When post-download authority matters, place a revocable, least-privilege credential in the file rather than assuming the claim limit controls its future use.

Monitor the underlying credential or workflow and rotate access if the wrong participant may have claimed the file. Preserve only the audit information your policy requires without copying plaintext into logs. For ongoing records and collaboration, use a managed document system with individual accounts and auditable retention.

Related guidance

• Compare secure links with email
• Review implemented Dead Drop behavior
• Understand attachment encryption
• Browse all secure sharing guides