The Offline Private Key Protocol (OPKP) is a cryptographic protocol to prevent unauthorized access to back up or archive data.
The protocol results in a public key that can be used to encrypt data and an offline private key that can later be used to decrypt that data.
As the protocol does not provide rules on the strength of the encryption methods and keys to be used, the security of the protocol depends on the actual cryptographic implementation.
When used in combination with strong encryption methods, the protocol can provide extreme security.
Initially: When archiving or creating a backup, for each session or file: To restore backed up or archived data: