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libove 05-22-2021 01:39 AM

SecureCRT (v7.3.7) ssh-keygen file format compatibility?
I've seen this discussed many years in the past, but the advice received back then doesn't seem to work. That is, a decade ago VanDyke stated that SecureCRT can read SSH key files as generated by ssh-keygen, but I'm still getting "Unknown file format".

Using SecureCRT v7.3.7.
Generated OpenSSH keypair with:
ssh-keygen -b 2048 -t rsa -f id_rsa2048 -N {passphrase}
Configured a session in SecureCRT for PublicKey (only), selected to a Session keyfile, choosing the file "id_rsa2048".
On connecting the first time, I do get the proper Server host key recognize/change/accept dialog once; and then on all connection attempts SecureCRT fails with:

"The private key file could not be found:

Note that the public key and private key file must have the
same name (e.g. "" and "Identity") and must be
located in the same folder.

Unknown file format"

Here's a redacted copy of the contents of
ssh-rsa AAAAB3NzaC1yc2EAA.......................(about 240 characters total).........I2CaZhwiCbKHpFwd myusername@myhostname

I generated the id_rsa2048 file with the same user as whom I'm running SecureCRT, and I've confirmed that there are no weird ACLs that would stop me (running SecureCRT) from reading these/my files.
So the "Unknown file format" error would suggest that SecureCRT v7.3.7 is having a problem reading the RSA 2048 key files generated by ssh-keygen.

What am I doing wrong?

many thanks,

bgagnon 05-23-2021 07:59 PM

Hi Jay,

Version 7.3.x is about 8 years old itself! :)

It's often useful to see trace options output which provides debugging information that may help us better understand the problem that you're experiencing.

To enable trace options output:
  • First, open SecureCRT's main File pull-down menu and select Trace Options. If you open the File pull down menu again you should see a checkmark next to Trace Options, indicating that troubleshooting output is now enabled.
  • Next, connect to the remote machine. With trace options enabled, you will notice debugging information displayed in the terminal window that isn't normally there by default when SecureCRT is attempting to establish a connection, and at certain times throughout the lifetime of the connection.
  • Once the problem occurs, please right-click inside the terminal window and choose Select All, then right-click again and choose Copy to transfer the information to the clipboard.
  • Finally, open a text editor, paste the information from the clipboard into the editor program, and save it as a text file.
Since trace options can contain sensitive information, feel free to send it as an attachment via email to Please reference "Attn Brenda - Forum Thread #14539" in the subject line.

NOTICE: The requested troubleshooting data may include sensitive information (usernames, passwords, publicly-accessible host names or IP addresses, etc.).

Please redact sensitive information that would not be appropriate for email communication prior to sending the requested information.

If there is sensitive information that must be conveyed in order to provide a complete picture of the scenario you're facing, please let us know and we will set up a secure upload mechanism that can be used.

bgagnon 05-24-2021 10:11 AM

Hi Jay,

Version 7.3.7 is too old to support reading private keys generated with newer versions of OpenSSH's ssh-keygen utility. Is the problem resolved with this same key file if you use the current version of SecureCRT, v9.0.2?

libove 05-26-2021 07:07 AM

Thanks Brenda, v9 in trial mode does seem to be able to read the ssh2 keygen file.
Ok, so, time to upgrade anyway... to the license page, Batman! :-)

bgagnon 05-26-2021 08:06 AM

Hi Jay,

Na na na na na na na na ... BATMAN!

I am glad the current, official release has the support you need. :)

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