(cache) Tarsnap - Online backups for the truly paranoid

Tarsnap is a secure, efficient online backup service:

Encryption: your data can only be accessed with your personal keys.
We can't access your data even if we wanted to!
Source code: the client code is available.
You don't need to trust us; you can check the encryption yourself!
Deduplication: only the unique data between your current files and encrypted archives is uploaded.
This reduces the bandwidth and storage required, saving you money!

Tarsnap runs on UNIX-like operating systems (BSD, Linux, MacOS X, Cygwin, etc).

Tarsnap uses a prepaid model based on actual usage:

Storage:	250 picodollars / byte-month of encoded data ($0.25 / GB-month)
Bandwidth:	250 picodollars / byte of encoded data ($0.25 / GB)

There are no other fees — Tarsnap has no fixed costs or minimum monthly fees.

Consider a typical backup scenario:

Alice begins a backup, which takes a complete snapshot of her files.
She does not need to decide whether to do a "full backup" or "incremental backup". [Why?]
Tarsnap automatically finds the unique data within her files.
Only this data is uploaded and stored. [How?]
Alice pays less than $5/month.
Even though she has thousands of daily backups, adding up to several terabytes of non-unique data. [Why?]
Alice's data is secure.
Even if an attacker (Mallory) breaks into Tarsnap's storage, he lacks her private keys and thus cannot read or modify her data. [Why?]

Major changes since version 1.0.36:

tarsnap-key(gen|mgmt|regen) now accept a --passphrase-time option, which specifies the duration to be spent on computing the derived keys used for encrypting the tarsnap key file.
tarsnap now accepts a --keep-going option when deleting or printing statistics about multiple archives.
tarsnap-keymgmt now accepts a --print-key-permissions option for listing the permissions contained in a key file.
tarsnap --print-stats now accepts a --csv-file option for printing statistics in comma-separated-value format.
tarsnap now accepts a --verify-config command which exits silently after checking the configuration file(s) for syntax errors.
tarsnap now looks for a server named "v1-0-0-server.tarsnap.com" instead of the historic "betatest-server.tarsnap.com" hostname. This should have no user-visible effect in most configurations.
tarsnap now correctly warns if a sparse extract fails due to hardlinks.
tarsnap now prints a warning if creating an empty archive.

You can see all of the changes between 1.0.36 and this version in our tarsnap git repository.