The invention of public-key cryptography was of central importance to the field of cryptography and provided answers to many key management problems for large scale networks. For all its benefits, however, public-key cryptography did not provide a comprehensive solution to the key management problem. Indeed, the possibilities brought forth by public-key cryptography heightened the need for sophisticated key management systems to answer questions such as the following:
"How can I easily encrypt a file once for a number of different people using public-key cryptography?"
"If I lose my keys, how can I decrypt all of my files that were encrypted with those keys?"
"How do I know that I really have Alice’s public key and not the public key of someone pretending to be Alice?"
"How can I know that a public key is still trustworthy?"
The paper discusses public key cryptography and its use in applications such as Key Agreement, Data Encryption and Digital Signature. The paper discusses some public key algorithms such as DH, RSA, and DSA and also gives working explanations of these algorithms.