tarsnap-keyregen -- generate a key file for use with tarsnap-recrypt(1)
tarsnap-keyregen --keyfile key-file --oldkey old-key-file --user user-name --machine machine-name [--passphrased] [--passphrase-mem maxmem]
tarsnap-keyregen generates a set of cryptographic keys which are compati- ble with an existing set of cryptographic keys, registers with the tarsnap server, and writes a key file for use with tarsnap-recrypt(1) and tarsnap(1). The term "compatible" here means that it is possible to re- encrypt archives stored with the first set of keys to be stored with the second set of keys. The --keyfile, --user, --machine, and --oldkey parameters are all required. If the --passphrased option is specified, the user will be prompted to enter a passphrase (twice) to be used to encrypt the key file. If the --passphrase-mem maxmem option is specified, a maximum of maxmem bytes of RAM will be used in the scrypt key derivation function to encrypt the key file; it may be necessary to set this option if a key file is being generated on a system with far more RAM than the system on which the key file will be used.