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I'm setting up automated backups with duplicity, but there's something I don't get. I have imported my own public GPG key, but it seems that duplicity wants the private key as well. It was my understanding that the public key was used to encrypt the data, and the private key to decrypt it. Therefore, I see no reason why the private key would be needed here.

Please enlighten me :)

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I don't know duplicity, but probably it's needed to sign the backups. What options are you using? – Matteo Italia Sep 10 '11 at 14:26
If you're worried about security, why not make a second key-pair and give it that private key - as long as you remember which public key to use to get the backups again, that should work? – deanWombourne Sep 10 '11 at 14:28
@Matteo: You're right, it's because it's trying to sign the data. That's too bad I can't mark your comment as accepted! deanWombourne: Yes, I guess it would work too. – Executifs Sep 10 '11 at 14:31
@Executifs: well, this can be quickly fixed. :) – Matteo Italia Sep 10 '11 at 14:37

migrated from stackoverflow.com Sep 10 '11 at 15:34

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I don't know duplicity, but probably it's needed to sign the backups.

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Could you elaborate on why signing would be needed? – Simon Sheehan Sep 10 '11 at 15:38
If you mean "why would you need signing", it's to make sure that nobody modified the backup after the signature. If it's "why do you need a private key for signing", it's because you use it to encrypt the hash, so that everybody can check it (decrypting it with the public key) but nobody can recreate it after tampering the data. – Matteo Italia Sep 10 '11 at 15:55

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