SSH skips public key authentication for a key, but works with another key

simopal6 · 07-06-2011, 05:13 AM

Hello everyone,
I have a little problem :-)

For years, I've been using SSH with public key authentication to connect to a remote server, and my private key is formatted like this:

Code:

-----BEGIN DSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: DES-EDE3-CBC,6EAFBBA66B440AE1

stuffstuffstuff
-----END DSA PRIVATE KEY-----

Now I need to create another key for another user on the same server, so I've run ssh-keygen and the output private key is something like

Code:

-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED 
DEK-Info: AES-128-CBC,7B196CE88FF664EEC250AFD52F55319A

stuffstuffstuff
-----END RSA PRIVATE KEY-----

So basically the only difference is that the new one is RSA and uses a different encryption algorithm

Anyway, if I set my .ssh/config file to use the new key (or if I rename it to "id_rsa"), ssh just skips the step when it asks for the passphrase, and goes directly to password authentication. However, in the end, it says "Permission denied (publickey,password,keyboard-interactive)."

Another thing... While the working key's public part is like:

Code:

---- BEGIN SSH2 PUBLIC KEY ----
Subject: simopal6
Comment: "[2048-bit dsa, simopal6@simone-nb, Mon Jul 18 2005 20:10:27]"
stuffstuffstuff
---- END SSH2 PUBLIC KEY ----

the new one is

Code:

ssh-rsa stuffstuffstuff simopal6@simopal6-nb

Could this difference be important?

I've tried creating a new key which uses DSA, but I got the same result...

Does anyone know what the cause to this might be?

Thank you!

AlucardZero · 07-06-2011, 08:33 AM

Quote:

Originally Posted by simopal6

the new one is

Code:

ssh-rsa stuffstuffstuff simopal6@simopal6-nb

That is how all RSA pubkeys look.

You need to enable verbose logging with ssh -vv and try again, reading the output for clues.

You could also look for clues in the server's authentication (secure) log, or stop SSHd on the server and rerun it in debug mode (man sshd) to get the server-side messages.