Symmetric key encryption has the major problem of how to securely distribute the keys. A multiple set of encryption schemes has been produced to manage the problem of two remote parties setting up a secure connection link, even over the web. These encryption schemes are known as public-key encryption.
With public-key encryption, there are two keys as one key encrypts the information, and the second key decrypts the information. In this scheme, one of the keys is designated as the private key and the other is the public key.
The private key is held in classified by the owner of the record and the public key is announced freely and extensively to everyone in the world. Lists of public keys can be written anywhere. It is moderate to learn the public key of the President of the United States. If the single possesses a private key and has written the corresponding public key, two elements are possible −
Secure delivery to the individual − Any other person in the world can encrypt a message with the individual’s public key and deliver it to the individual. Because only the individual has the private key, the message cannot be interpreted by anyone except that individual.
Guaranteed authenticity from the individual − If the individual encrypts a message with a private key, then each one in the world can test that the message is unique because the only way to decrypt the message is with the person’s unique public key.
If a user needs to upload planning numbers or budget numbers to the data warehouse, this scheme could be used to guarantee that the numbers indeed came from the designated individual.
If two different individuals (A and B) have public and private keys, then they can engage in secure communications −
Secure communications between parties − Person A encrypts the outgoing message with B’s public key. But inside the message, person A adds this signature encrypted with A’s private key. B receives the message and strongly decrypts the frame of the message with B’s private key. B then verifies the authenticity of A’s signature by decrypting the signature with A’s public key.
This scheme is the most secure communications over insecure media such as the web or a public telephone line. Since it is computationally expensive, this scheme is often used to securely exchange a higher-performance symmetric key that both parties can use temporarily to rapidly exchange large amounts of data.
Secure retrieval of a person’s or company’s public key − It can connect to the CA’s Web server and request the public key for the desired individual or company. It can receive the CA’s response, encrypted by its private key. It can decrypt the message with the CA’s public key, verifying that indeed the message came from the CA.