*Recent amanda-user discussion on encryption*: Difference between revisions

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== Different encryption configuration ==
#redirect [[Encryption]]
 
'''Transport  Data          Tag'''<br/>
no      no       A<br/>
yes            no       B<br/>
no              yes          C<br/>
yes            yes          D [separate encryption, back to clear on server]<br/>
yes            still        E [client encrypts, server passthrough]<br/>
 
 
In scenarios A and C, and eavesdropper on the network can observe the
data.  In B D and E an eavesdropper cannot.
 
In secenarios A and B, one can retrieve the data from backup tapes
without keying material.  This is perhaps obvious, but very important
for backups.
 
In C, D, and E, the backup tapes are encrypted.  Thus, one could store
them someplace where you trust people not to destroy them but you
don't trust them to read them.  This can make some sense for
particularly sensitive data.
 
In E, the backup data doesn't appear on the server in plaintext.  This
can be useful for backing up clients with particularly sensitive
data.  To really make sense, the client should be configured so that
it will only honor dump requests to a preconfigured set of public
keys.
 
== SSH ==
ssh provides transport encryption and authentication. The only caveat is that the amanda binary needs to be installed at the same location in the server as well as in the client since server is running:
/path/ssh -l <CLIENT_LOGIN> client.zmanda.com $libexecdir/amandad
to start the backup process.
 
While this is possible, it has two disadvantages:
 
1. You need to set up keys for both, ssh _and_ amanda.
 
2. You need to set up ssh keys either by storing the passphrase in
cleartext or use ssh-agent.  Using ssh-agent has security-flaws, too.
In addition, with ssh-agent, you will need to type the passphrase
at least once after every reboot.  Not very suitable for a
fully-automated backup-system, IMHO.
 
When you use a public key on the client to encrypt, you can lock away
the private key in a secure place.  Both, transport _and_ storage will
be encrypted with such a setup.

Latest revision as of 22:58, 31 May 2007

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