SecArchive: Provable Data Possession for Archival Storage Deterring Subcontracting Attacks in Multi-Cloud Multi-Copy

SecArchive is a system that verifies data hasn't been lost or corrupted in multi-cloud storage (where copies of data are kept across multiple cloud providers) while preventing subcontracting attacks, where cloud servers illegally hand storage tasks to third parties. The system uses Provable Data Possession (PDP, a method to verify data integrity without downloading everything), and it's designed to be more efficient than older approaches by reducing computational work when managing multiple copies of archived data.