public+key+encryption

=Public Key Encryption= Main Menu

Overview
Public key cryptography refers to a cryptographic system requiring two separate keys, one to encrypt the plain text, and one to decrypt the cyphertext. One of the keys is published (public) and the other is kept private. If the encryption key is published the system enables private communication from the public to the unlocking key's owner. If the decryption key is published the system serves as a signature verifier of documents locked by the owner of the private key.

This cryptographic approach uses asymmetric key algorithms such as RSA. Some algorithms have the public key/private key property. In this situation, neither key is derivable from knowledge of the other. Not all asymmetric key algorithms have this property but those that do are particularly useful and have been widely deployed. Although unrelated, the key pair are mathematically linked. The public key is used to transform a message into an unreadable form, decryptable only by using the (different but matching) private key.

Unlike symmetric key algorithms, a public key algorithm does not require a secure initial exchange of one, or more, secret keys between the sender and receiver. The algorithms make it easy for the intended recipient to generate the public and private keys and to decrypt the message using the private key. It is also easy for the sender to encrypt the message using the public key, however it is extremely difficult for anyone to figure out the private key based on their knowledge of the public key. They are based on mathematical relationships that have no efficient solution.