How does public key cryptography work??

Question

What will be an ideal response?

Answer 1

?Consider a business that has its headquarters in New York. A branch office in Atlanta wishes to send secure data to the New York office. The New York office sends the public key to Atlanta and keeps the private key locked up safe in New York. The Atlanta office uses the public key to encrypt the data, and sends the encrypted data to New York. Only the New York office can decode the data, because it is the only one possessing the private key. Even if other parties intercept the transmission of the public key to Atlanta, nothing will be gained, because it is not possible to deduce the private key from the public key. Likewise, interception of the encrypted data will lead to nothing, because the data can be
decoded only with the private key.?For a more familiar example, consider a situation in which a person browsing the Web wishes to send secure information (such as a credit card number) to a Web server. The user at a workstation clicks on a secured Web page and sends the appropriate request to the server. The server returns a "certificate," which includes the server's public key, and a number of preferred cryptographic algorithms. The user's workstation selects one of the algorithms, generates a set of public and private keys, keeps the private key, and sends the public key back to the server. Now both sides have their own private keys, and they both have each other's public key. Data can now be sent between the two endpoints in a secure fashion.