Design a backend system that ingests video recordings from body-worn and vehicle-mounted cameras. These devices often upload over unreliable networks, and the footage may later be used as legal evidence. The platform must support very large files, security scanning, and a tamper-evident chain of custody.
Resumable large-file uploads
Video files can be multiple gigabytes in size. The upload flow must allow clients to send data in chunks and resume after dropped connections or network failures. Because the cloud provider's native multipart finalization cannot be fully trusted, your design must be able to prove server-side which bytes were received and how the complete object was assembled.
Quarantine and security scanning
Every newly uploaded blob must be treated as untrusted. Before the content is made available to users or downstream systems, the platform must run security checks such as malware detection and file-type validation.
Tamper-evident chain of custody
The system must maintain an auditable, append-only history of every action performed on a video, including upload, scan results, storage moves, access/download/export, retention or legal-hold changes, and deletion. This history should help establish that the footage was not modified after it was ingested.