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Secure File Sharing
How chunked encryption, presigned uploads, and safe downloads work for files.
Files are larger and require careful handling to stay fast and secure.
Solun encrypts each chunk with a unique IV and keeps keys out of the server in secure mode.
Chunking and encryption
Files are split into fixed-size chunks before upload.
Each chunk uses the same key but a different random IV to avoid reuse risk.
Direct-to-storage uploads
The browser uploads encrypted chunks directly to storage using presigned URLs.
The API only sees metadata, never the file contents in secure mode.
Safe downloads
Downloads fetch metadata, stream encrypted chunks, and decrypt locally in the browser.
After assembly, the file is offered as a download and can auto-start on reveal.
Reliability and resume
Upload progress is saved per chunk so a refresh can resume from the last successful part.
Pending uploads are cleaned automatically, and expired files are removed by policy.