[problem] OpenSSH SSH2 private key

I can't connect using SSH2 private key :( But it works with SCRT & SecureFX programs. Did I do someting wrong or WinSCP don't support this method?

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Authentication log (see session log for details):
Using username "test".
Unable to use key file "C:\Documents and Settings\user\Desktop\.ssh\id_dsa" (OpenSSH SSH2 private key)
No supported authentication methods left to try!

Connection has been unexpectedly closed. Server sent command exit status 0.

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. Looking up host "192.168.0.22"
. Connecting to 192.168.0.22 port 22
. Server version: SSH-2.0-OpenSSH_3.5p1 FreeBSD-20030924
. We claim version: SSH-2.0-WinSCP-release-3.6.1
. Using SSH protocol version 2
. Doing Diffie-Hellman group exchange
. Doing Diffie-Hellman key exchange
. Host key fingerprint is:
. ssh-dss 1024 dd:b9:a8:29:0a:d8:22:3c:cc:52:36:f9:32:e8:51:cf
. Initialised AES-256 client->server encryption
. Initialised AES-256 server->client encryption
! Using username "test".
. Reading private key file "C:\Documents and Settings\user\Desktop\.ssh\id_dsa"
. Unable to use this key file (OpenSSH SSH2 private key)
! Unable to use key file "C:\Documents and Settings\user\Desktop\.ssh\id_dsa" (OpenSSH SSH2 private key)
! No supported authentication methods left to try!
. No supported authentications offered. Disconnecting
* (ESshFatal) Authentication failed.

You need to convert your OpenSSH key to Putty format. Use Puttygen tool.

Thanx :)

martin wrote:

You need to convert your OpenSSH key to Putty format. Use Puttygen tool.

% puttygen id_dsa -o id_dsa.ppk

will convert the OpenSSH key to one PuTTY understands.

Hi Martin,

I'm using CoreFTp and on the other side they are using WinSCP.
I tried to convert a SSH private key to a Putty using PuTTYgen.
I got a error message "Couldn't load private key (unsupported cipher)"

Need help. Thanks

PLEP wrote:

I'm using CoreFTp and on the other side they are using WinSCP.
I tried to convert a SSH private key to a Putty using PuTTYgen.
I got a error message "Couldn't load private key (unsupported cipher)"

What cipher does your key use?
Can you post the key header?

Hi

Cipher method when using 'generate key pair' on CoreFTP server side (not possible to change it)

Here is the header:

-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: DES-EDE3-CFB

Thanks

PLEP wrote:

on CoreFTP server side

Are you sure you do not confuse server's host key with your account private key? Account private keys should not be generated on server-side.

Anyway, PuTTYgen does not support this cipher indeed. You would need to re-encrypt the key using another tool before you will be able to import the key to PuTTYgen.

Seem to have solved this. Under some *NIX system (Linux or, as in my case, FreeBSD) change directory to where the private key is. Lets say it is named "private.key".
Run this:
(Don't copy-paste it, I had to change one symbol because keygеn is a forbidden word at this forum, as it says, and I could not post it.)
It is basically for changing the password for the private key.
It asks now for the filename, enter: private.key
Then it asks for the current password, enter it
Then it asks for the new password twice, you can enter something new or just the same one.
It will re-write the file private.key but now it is coded with AES-128-CBC which PUTTY DOES understand! Now it can be imported by puttygen.
This way I solved the problem with the key coded with DES-EDE3-CFB which nothing could understand except one non-freeware program!

I had the same problem with my SFTP server (Solarwinds Serv-U) generating CFB keys that cannot being understood by PuttyGen.
Please refer to this page : https://parkwharf.com/blog/cipher-feedback-encryption-woes-on-windows/

With a simple command you can convert from CFB to CBC:

Note : change "dsa" by "rsa" if your CFB key is using RSA

Converted successfully with PuttyGen 0.73