Creating SSH (PKI) pairs for SFTP with PuTTYgen

Using the free SSH key generating tool, PuTTYgen, you can quickly create a matching public and private key pair for your Hosted~FTP~ users to authenticate using SFTP protocol. The user will require to have their username and private key that matches the public key to authenticate. Follow the steps below on how to download the PuTTYgen, and then generate your own SSH keys.

Downloading PuTTYgen

Download the program following this link, locating under the Alternative Binary Files list, find puttygen.exe (a RSA and DSA key generation utility) to download the right 32-bit or 64-bit for your device.

Generating your own SSH (PKI) keys for SFTP

1. Once you open the program, make sure that the type of key to generate is set to RSA with 2048 bits, then click on Generate.
   
2. Next, follow the instructions on screen by moving your mouse around in the grey blank area to generate your unique public key pair until the generating bar is complete.
   
3. Once generated, you’ll now have a public key that you can copy and paste, or save the public and private key to use at a later date onto your device. *Note: You have the option to add a passphrase to access the private key. This is not recommended for SSH key authentications that are used with scripts/automations that do not have the capability to enter the passphrase.
   

Setting up SSH key pairs to authenticate for your user

1. Once you have generated your public and private key pair., head over to your user’s tab and open the designated user’s settings that you want to apply the SSH key pair to. In their settings, scroll down to Use a public key for SFTP authentication and paste the entire public key into the field and save.
   
2. Next, share the private key to your user. They can now authenticate via SFTP with username and SSH key.

For more information about SSH (PKI) keys, please view our article here.