Cumulus Vault

Cumulus Vault is a free and open source command-line tool for encrypted, verifiable backups. Files are encrypted on the client with ChaCha20-Poly1305 in authenticated chunks, stored on a local disk or on Filecoin, and recorded in an append-only, hash-chained ledger. Restore drills re-download, decrypt and check each backup against its recorded digest, and the ledger head can be timestamped in Bitcoin with OpenTimestamps so anyone can prove the backup history was not rewritten. It gives small organizations ransomware-resistant, tamper-evident backups without trusting a storage provider with plaintext.