PuTTY Key Generator
PuTTY Key Generator (also known as PuTTYgen) is a small, yet efficient program that can generate RSA and DSA keys for use with the OpenSSH 'authorized_keys' file.
The program comes ready out-of-the-box, hence it does not need installation. Within the main window, you will find a well-organized set of options that aren’t difficult to operate.
PuTTY Key Generator is able to create both public and private keys, but the first step you need to take is to choose the type of key to be generated and here you have three options: SSH-1, SSH-2 (both are RSA specific) or SSH-2 DSA.
It is also important to customize the strength of the key, which is given by the number of bits in the output – the higher the amount, the stronger the key. At this point, you are ready to initiate the generation engine and your intervention might be required in doing so.
The success and completion of the process depends on the random data that is necessary for the delivery of the key and as such, you are asked to move the mouse around a blank area in order to include as much random information as possible.
Prior to saving the key, it is recommended that you secure it with a passphrase that should be strong enough in order to prevent decryption from an outside party.
Overall, PuTTY Key Generator paves the way to secure SSH authentications by generating RSA or DSA keys with an adjustable size. The output key files can be used with any third-party application that supports SSH.