In the world of cryptography, there are two basic types – symmetric and asymmetric cryptography. The symmetric cryptography both the encryption and decryption are done through the same key or pass phrase. However in the case of asymmetric cryptography, the encryption and decryption processes use a different set of keys.
RSA and DSA are asymmetric cryptographic algorithms. They require two keys – a public key and a private key. The public key is used for data encryption but both keys are needed for the decryption. The public key, as the name suggests, is shared with everyone while the private key is kept secret by the person who created these keys.
It is very easy to generate RSA or DSA key pairs for the Linux operating system users. They can install OpenSSL and generate RSA key pairs through the terminal interface. But for the Windows users, we have to use a utility like PuTTY Key Generator (or PuTTYGen).
PuttyGen is created by the same developer who created the popular networking tool PuTTY. It can generate many different type of keys such as RSA, DSA, ECDSA, EdDSA, SSH-1(RSA). After selecting the key type and choosing the number of bits in the keys, we can click on the button labeled “Generate”.
After moving the mouse around on the PuTTYGen window to provide good amount of entropy for the key pair generation. The moving of the mouse is needed to avoid closeness or similarness between the key pairs. Once the key pairs are generated we can save them to a folder.
PuTTY Key Generator is a very useful application for the Windows users who do not want to use command line tools like OpenSSL. Through its easy-to-use GUI interface, we can quickly create public and private key pairs for a number of cryptography algorithms.
You can download PuTTY Key Generator (PuTTYGen) from https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html.