Safecloud encrypts streaming data across browser nodes without trust

Safecloud, introduced by Gregory Magarshak in a new arXiv paper, proposes a distributed, encrypted storage and streaming network that keeps data completely private from infrastructure providers. The system splits files into encrypted chunks on the client device and distributes them across Drops—browser tabs storing ciphertext in IndexedDB—and Jets, which are federated routing servers. Crucially, neither Drops nor Jets ever hold encryption keys or see plaintext, enabling a zero-trust model for content distribution. A one-root key hierarchy allows every key to be derived deterministically from a single root, granting owners or authorized grantees range-scoped access without exposing the full tree. Convergent content addressing deduplicates identical content without revealing plaintext, and a combination of Merkle, key-derivation, and access trees ensures integrity, confidentiality, and authorization are verified in parallel.

Beyond architecture, Safecloud introduces a novel streaming index built directly into the key tree, enabling O(1) segment key derivation for seeking. Parallel tracks (video, audio, captions) are independent subtrees, unlockable per-track and per-segment—a feature Magarshak claims no prior encrypted storage network offers. To keep nodes honest, Safecloud employs a proof-of-storage challenge system with a single-signature verification and a chilling-effect Proof-of-Corruption. Storage and routing nodes earn Safebux tokens in a zero-sum economy that the paper argues is significantly cheaper than Filecoin's proof-of-replication sealing, which is slow and provides no confidentiality. The paper includes a threat model and an open-source reference implementation, positioning Safecloud as a practical step toward private, efficient cloud streaming.