Generate RSAv2 key in OpenSSH format in Windows

Question

I have to generate a key, RSA v2 in OpenSSH format. I am a bit confused. I am trying to generate it using Putty Key Generator. There I see an option SSH2-RSA, SSH1-RSA. So is SSH2-RSA the RSA2 key or it means something else. Also is this key in the OpenSSH format. I see that there is a conversion tab with 2 options: export OpenSSh Key and export ssh.com key. So I am not sure if the keys I have generated are in OpenSSH format.

Regards Ankur

Answer 1

Make sure you have version 0.65 - dated 20150725 - of PuTTY installed : the maintainer is pretty up-to-date with standards, so the key generated will be also.

The puttygen tool will create a private key that you can save in "PuTTY" format (using the Save private key button), "OpenSSH" or "ssh.com" format using the according option in the Conversions menu.

Since the public key part is not encrypted and is only text-based, the format is irrelevant.

Hope this help!

Answer 2

SSH-1 RSA means an RSA key for SSH version 1 (SSHv1)

SSH-2 RSA means an RSA key for SSH version 2 (SSHv2)

SSHv1 is fundamentally broken and should not be used.

http://www.employees.org/~satch/ssh/faq/ssh-faq-1.html

RSA works differently in SSHv1 vs. SSHv2 but I'm not aware of anything known as RSAv2.

https://security.stackexchange.com/questions/31624/what-is-the-difference-between-rsa1-rsa-in-regards-to-ssh-also-when-is-the-fi

I suspect all you want is a standard RSA key for SSHv2 in OpenSSH format which case you want to select the SSH-2 RSA option in PuttyGen then Conversion => Export OpenSSH key. Nobody should be using SSHv1 anymore without good reason.