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 and 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.


1 Answer 1


I just cited below from PuTTY manual:

Selecting the Type of Key

Before generating a key pair using PuTTYgen, you need to select which type of key you need. PuTTYgen currently supports three types of key:

An RSA key for use with the SSH-1 protocol.
An RSA key for use with the SSH-2 protocol.
A DSA key for use with the SSH-2 protocol.

The SSH-1 protocol only supports RSA keys; if you will be connecting using the SSH-1 protocol, you must select the first key type or your key will be completely useless.

The SSH-2 protocol supports more than one key type. The two types supported by WinSCP are RSA and DSA.

The WinSCP developers strongly recommend you use RSA. DSA has an intrinsic weakness which makes it very easy to create a signature which contains enough information to give away the private key! This would allow an attacker to pretend to be you for any number of future sessions. WinSCP’s implementation has taken very careful precautions to avoid this weakness, but we cannot be 100% certain we have managed it, and if you have the choice we strongly recommend using RSA keys instead.

If you really need to connect to an SSH server which only supports DSA, then you probably have no choice but to use DSA. If you do use DSA, we recommend you do not use the same key to authenticate with more than one server.

Reference link: https://winscp.net/eng/docs/ui_puttygen#generating

  • The SSH protocol 1 was deprecated in 2005. Aug 13, 2022 at 5:45

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