This example will show how to convert the OpenSSH key format to ssh.com (Tectia enterprise products) key format. It will also show you how to import the converted keys into ssh.com's Secure File Transfer Client.
1. Copy your private OpenSSH key from your unix system to your local windows machine. The private key is in your home dir ~/.ssh/. Usually it's called id_(something) like id_dsa. I'm going to call mine id_dsa for this example. Make sure your copy the file by transferring it over the network with scp/sftp, shared mount point you have to your your windows machine, or usb key. DO NOT cat the file in a terminal and then copy and paste it into a text editor on the windows machine. This will not work because of the differences in file formats of unix and windows.
2. Go and download Putty. Get the zip version from the website and unzip it. Find the program puttygen.exe in the unzipped files and execute it.
3. Click the "load" button. Select "files of all type" drop down. Then select all files. Point puttygen to your OpenSSH key that you copied over in step 1. Then click "open". Enter your keys pass phrase (If you have one. You should be using pass phrases on your keys.).
4. Click conversions->export->ssh.com key. Then save your converted private key with the name "id_dsa_sshcom". This is your converted private key. Names are important to the ssh.com program when importing keys. The key pair has to have matching names to be imported. You can call it anything you want but it has to take the format: key_name and key_name.pub.
5. Now click file->save public key. Save the public key with the name id_dsa_sshcom.pub in the same area (folder) you saved your private key in step 4. This is your public key that goes with your private key. Make sure the first part of the names match.
6. Open the ssh.com Secure File Transfer Client. Click edit->settings. Then go to user authentication->keys (in the left pane). Click the import button. Select "files of all type" drop down. Then select all files. Click the "Look in" drop down and point it to the folder where your "id_dsa_sshcom.pub" and "id_dsa_sshcom" files are. Select your public key id_dsa_sshcom.pub and click ok. Then ok out of the settings area. FYI: The ssh.com client will ask for the public key and then when it is selected is will match the private key that goes with it by the same name. Just without the .pub at the end.
7. Now you should be able to connect to any host that you have put your public keys on with ssh.com's Secure File Transfer Client.
8. After you have tested your connection make sure you delete your private key you copied over from your system when we started.