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mcloaked

Member

From: Yorkshire, UK

Registered: 2012-02-02

Posts: 1,279

[SOLVED] openssh 6.5 - can't add ed25519 key to agent

I have been switching over ssh keys from rsa to the new ed25519 keys in the recently released openssh package v 6.5.

Creating new keys with

ssh-keygen -t ed25519

is straighforward.

Copying the new public key to the authorized_keys file is also straightforward.  However I have been using the ssh-agent at /usr/bin/ssh-agent for some time perfectly successfully with rsa keys which have passphrases.

When trying to add the newly created key with ssh-add it fails:

 
$ ssh-add
Enter passphrase for /home/mike/.ssh/id_ed25519:
SSH_AGENT_FAILURE
Could not add identity: /home/mike/.ssh/id_ed25519

It would seem that this is possibly due to the new bcrypt format that the encrypted key is stored in not being recognised by ssh-add, so I tested this by removing the passphrase from the private key

$ cd ~/.ssh
$ ssh-keygen -p -f id_ed25519 -N ''
Enter old passphrase:
Key has comment 'id_ed25519'
Your identification has been saved with the new passphrase

Now the ssh-add command is quite happy - but now the key is stored in plain text and therefore less secure!

Does anyone know of a workaround for this so that the private ssh key can be stored in its bcrypt format, and still be used by the agent?

Edit after further work:  I just tried to add back in the passphrase, and now it works - I am puzzled as to what changed but it seems fine now!

i.e. After re-adding the passphrase with

$ ssh-keygen -p -f id_ed25519

Then I ran ssh-add again - this time it accepted it! Sorry for the noise.

Last edited by mcloaked (2014-02-03 13:36:17)

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Mike C