Every uploaded evidence file is assigned a unique reference (e.g. EV-2026-000001) and a SHA-256 integrity hash at the time of upload. This hash never changes; if a file needs to be replaced, a new evidence version is created rather than overwriting the original.

Chain of Custody

Every access to evidence (upload, view, download, review, accept, reject, restrict, export, legal hold, release) is recorded with the acting user, timestamp, IP address and action - an immutable log that cannot be edited through the admin interface.

Redaction

Reporters may mark personal information (their phone number, address, bank account, citizenship/NID, email) for redaction. A redacted public version is used for any public display, while the original is preserved for authorized review.

Storage

Evidence files are stored outside the public web root using randomly generated filenames. Uploaded files are validated by MIME type, extension, and file signature; executable file types are always rejected.