Session Transfer

Phase 4 adds separate file-transfer messages: offer, accept/resume, chunk, complete, and cancel. Only finalized packages—or incomplete packages explicitly marked recoverable—are eligible. Active recording packages are rejected.

The receiver checks expected size and available storage, writes numbered chunks, persists a checkpoint, resumes at the next missing chunk, assembles in deterministic order, and verifies the final SHA-256. The package is still treated as untrusted and must pass package validation before catalog insertion.

Transfer is user initiated and independent of local recording. Live-preview traffic remains separate; production transport may reduce or suspend preview bandwidth while a large transfer runs. Physical iPhone-to-iPad throughput, background behavior, and interruption recovery remain unvalidated without devices.

The Phase 3 protocol uses CryptoKit primitives in an application-defined design. Independent cryptographic and protocol review is recommended before use beyond controlled research environments.