Tarsnap - Online backups for the truly paranoid

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).

Start using Tarsnap now!

Tarsnap pricing

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.

Why use Tarsnap?

Dataflow chart of a typical backup with Tarsnap

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?]

Tarsnap news

Tarsnap 1.0.37 released - March 10, 2016

Version 1.0.37 of the Tarsnap client code is now available for download. This version adds several new options, including --passphrase-time option for increased security of passphrase-protected key files, along with minor bug fixes and some additional warnings about common user errors.

Tarsnap 1.0.36 released - August 21, 2015

Version 1.0.36 of the Tarsnap client code is now available for download. This version fixes a theoretically exploitable one-byte buffer overflow when archiving objects with long path names; a vulnerability which allows a corrupt archive to crash tarsnap; and two bugs which cause tarsnap to crash if the network is inoperative when it launches. This version also adds support for performing "dry runs" without tarsnap keys, which makes it possible to estimate tarsnap usage costs without first creating a tarsnap account.

Tarsnap book - March 18, 2015

Tarsnap Mastery, a book from respected technical author Michael W. Lucas about using Tarsnap, is now available in electronic and print formats.

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