Public key with Easy RSA

Hi all! Recently, I generated a public key with Easy RSA to setup a VPN following OpenVPN tutorials. I placed the key in ~/.ssh/authorised_keys and right now, I am trying to connect it through a SSH. I would copy private keys into the Windows host and then open up Putty. Then, I go to Connection --> SSH --> Auth and Browse for the private key.

Once I click “OPEN” nothing happens. I tried “Putty Gen Generator” as to change the format but got this message instead of “Unrecognised Key Format”. Why is that, how do I get it fixed??

Hello,
Please check the link below
Easy - RSA is a utility for managing X. 509 PKI, or Public Key Infrastructure. A PKI is based on the notion of trusting a particular authority to authenticate a remote peer; for more background on how PKI works, see the Intro-To-PKI document