Physalia: Redistribution-Resistant Content Protection for Decentralized Storage
Physalia secret-shares decentralized storage data so leaking protected content requires full redistribution bandwidth.
The paper presents Physalia, an access-control system for decentralized storage that secret-shares the data itself rather than only an encryption key, forcing an adversary to transmit the full content to leak it. A robustness transform turns any computational secret-sharing scheme into a robust one using signatures with ephemeral keys and constant-size metadata per share, instead of error correction. The authors prove the transform secure and evaluate Physalia on the Walrus decentralized storage system with an on-chain access policy.
- Secret-shares the data itself, not only the decryption key.
- Adversary must pay full data size in redistribution bandwidth.
- Robustness transform uses ephemeral-key signatures and constant metadata.
- Evaluated end-to-end on Walrus with an on-chain access policy.
From the original article
1 min read at arxiv.orgIn decentralized storage systems, access control is often implemented by encrypting the data before upload and sharing the decryption key with authorized parties. A leaked key, however, makes the data publicly accessible, which lowers the barrier to content piracy below that of traditional systems, where piracy requires redistributing the full data.
By Giacomo Giuliari · arxiv.org
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