How LimeShare works

End-to-end encrypted file transfer without accounts, explained step by step.

1. You pick files

Drop up to 3 files (3 GB each) into the page. Nothing is uploaded yet. Your browser generates a random 256-bit master key and derives separate keys for each file and for the metadata using HKDF.

2. Your browser encrypts

Each file is read as a stream and encrypted in 4 MiB frames with AES-256-GCM (the open LSC1 container format). The frame counter and a "last frame" flag are part of the nonce, and the header carrying the exact file length is authenticated — so a truncated, reordered or altered download is detected before any plaintext is released. File names, sizes, types and your message are encrypted into a separate manifest.

3. Ciphertext goes straight to storage

Encrypted bytes are uploaded in parallel parts directly from your browser to object storage using short-lived signed URLs. Our servers only coordinate: they never see, proxy or scan the bytes. When the upload finishes, the server checks that the stored object is exactly the declared length — to the byte — before the transfer becomes active.

4. You share a link

The link looks like limeshare.org/d/ID#key.token. Everything after # is the URL fragment, which browsers never send to any server. It holds the decryption key and an access token; we store only a SHA-256 hash of the token. Optionally the key is additionally wrapped with a password (Argon2id), and you can show the link as a QR code.

5. The recipient decrypts locally

The recipient's browser presents the token, receives the encrypted manifest and signed download URLs, downloads the ciphertext from storage, verifies every frame and writes the decrypted file to disk as a stream — even for multi-gigabyte files. Nothing is installed.

6. Everything disappears

Transfers are deleted precisely at expiry (48 hours by default, or 1/6/24 hours if you choose), immediately after the first download with "burn", or whenever you press Destroy. Storage-level lifecycle rules act as a second safety net, and metadata rows are purged from the database afterwards.

Details: security model · FAQ · send files now