Creating SSH Keys

To log in to other Aspera servers with public key authentication, create key pairs from the command line. Follow the instructions below.

Create an .ssh folder in the home directory if it does not already exist.
```
$ mkdir /home/username/.ssh
```
Go to the .ssh folder and continue:
```
$ cd user_home_dir\.ssh
```
```
$ cd <path-to-user-home-dir>/.ssh
```
Run ssh-keygen to generate an SSH key-pair.
Run the following command in the .ssh folder. The program prompts you for the key-pair's filename. Press ENTER to use the default name id_rsa. For a passphrase, you can either enter a password, or press return twice to leave it blank:
```
# ssh-keygen -t rsa
```
Retrieve the public key file.
When created, the key-pair can be found in your home directory's .ssh folder (assuming you generated the key with the default name id_rsa):
```
/home/username/.ssh/id_rsa.pub
```
Provide the public key file (for example, id_rsa.pub) to your server administrator, so that it can be set up for your server connection.

Note: You must have the server administrator install your public key file on the server in order to successful sync with it.
Use the key in an async session.
Use the option -i private_key_file, instead of -w password, as in the following example:
```
$ async -N TestBackup -d /tmp/dir -r user@server:/tmp/dir -i PATH_TO_THE_PRIVATE_KEY_FILE
```
Note: Your private key and public key must be located in the same directory.