I need to send a public key to my bank. I'm using CoreFTP which allows the generation of keys using RSA. It says that it generates "OpenSSH compatible certificates [sic]" when you press the generate keys button.

The keys it generates have


at the start (and then the key and then an end marker).

My bank rejects my public key and says it should begin ssh-rsa.

I suspect "RSA" and "OpenSSH" have variations that neither end are being clear about what they generate/expect.

How can I convert my key from the format the CoreFTP is providing to the format my bank wants?

1 Answer 1


I believe the reason is that the CoreFTP is actually generating OpenSSL keys and not OpenSSH formatted ones.

Perhaps your question is already answered on Stackoverflow?


From Victor Matare on SO:

You can do the same with ssh-keygen:

ssh-keygen -f pub1key.pub -i -m PKCS8

will read the public key in openssl format from pub1key.pub and output it in openssh format.
  • Thanks. I didn't look on SO as I thought my question would be off topic there. Apr 23, 2012 at 9:00

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