windows，linux，mac生成ssh public key 和 private key

https://help.launchpad.net/YourAccount/CreatingAnSSHKeyPair

Creating the key

How you create your SSH key pair depends on which operating system you use.

If the instructions for your operating system are not here, get in touch to request them or, if you know what to do, add them to this page.

Linux/Cygwin/MacOS

Step 1: Install OpenSSH. On Ubuntu, you can install OpenSSH by opening your terminal and typing:

sudo apt-get install openssh-client

With Cygwin you can follow the instructions here: http://pigtail.net/LRP/printsrv/cygwin-ssh.html

Step 2: Once OpenSSH is installed, stay in the terminal and type:

ssh-keygen -t rsa

Step 3: When prompted, press Enter to accept the default file name for your key.

Step 4: Next, enter then confirm a password to protect your SSH key. Your key pair is stored in ~/.ssh/ as id_rsa.pub (public key) and id_rsa (private key)

Now you need to upload the public portion of your SSH key to Launchpad.

Possible Step 5: You may need to run ssh-add with the id file if you created an id file other than ~/.ssh/id_rsa. Do ssh-add /path/to/file/id_rsa_newfile . If you’re on the Mac, you can execute the following on the command line:

cat ~/.ssh/id_rsa.pub | pbcopy

Windows (PuTTY)

Step 1: Download the PuTTY Key Generator from here:http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html

Step 2: Run puttygen.exe and click the generate button. PuTTYGen will ask you to move your mouse around in the blank area to generate entropy.

Step 3: Set a key passphrase and confirm it.

Step 4: Click "Save public key" and choose a location to save it. Click "Save private key" and choose a secure location to save it. You must keep this secret key safe!