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

2 Answers 2


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!

  • Thanks a ton ionrelex. So the SSH2 here stands for RSA v2 right? Oct 21, 2015 at 15:57
  • @AnkurBhatia I looked around about this and didn't find any concrete response, but according to this link giving information about RSA revision 2.0 and dating back October 1998, I'm pretty sure the puttygen tool can't generate a key at a lower version.
    – ionreflex
    Oct 21, 2015 at 17:23

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.


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


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.

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