Terminalski uses the same file format as OpenSSH for private and public keys. Hence you can interchangeably use them regardless of where those keys are generated as long as their key types are supported. For example, if you have a ECDSA private and public key pair generated with OpenSSH 'ssh-keygen', you just need to copy them to Terminalski Home Folder (i.e., ssh\keys) and vice versa. However, you cannot use private and public keys generated in Terminalski for 'RSA (Windows Hello)' type with OpenSSH; OpenSSH simply does not support directly using Windows Hello and such files will not be recognized by OpenSSH.
Please note that when you are using private keys generated with OpenSSH tool in Terminalski, you need to make sure that the file name for a public key must be the same as its corresponding private key except for the file extension; a public key file must have a .pub file extension. For example, if your private key file is named 'myserver.key', its public key file must be named 'myserver.key.pub'.
For your information, if you somehow end up with an OpenSSH private key without its paired public key, you can easily generate it from the private key with Windows built-in 'ssh-keygen' command-line tool. For example, if you only have a private key named 'my_private_key', open Windows Command Prompt and go to the folder where the file exists, and execute the following command:
ssh-keygen -y -f my_private_key > my_private_key.pub
All in all, when you want to import private and public key pairs generated for OpenSSH, you just need to check their file name extension and copy them to the private key folder in Terminalski Home Folder: ssh\keys
