encryption :: essays research papers

Traditional coding is based on the sender and manslayer of a gist knowing and victimization the very(prenominal) cryptical linchpin the sender uses the secret key out to encrypt the message, and the receiver uses the same secret key to decrypt the message. This method is known as secret-key cryptography. The main problem is getting the sender and receiver to agree on the secret key without any wiz(a) else finding out. If they are in separate visible locations, they must trust a courier, or a phone system, or some other transmission system to not disclose the secret key being communicated. Anyone who overhears or intercepts the key in transit quarter later read all messages encrypted using that key. The generation, transmission and storage of keys is called key management all cryptosystems must deal with key management issues. Secret-key cryptography often has difficulty providing secure key management.Public-key cryptography was invented in 1976 by Whitfield Diffie and Mar tin Hellman in order to solve the key management problem. In the bracing system, each person gets a pair of keys, called the humankind key and the hidden key. Each persons public key is published while the offstage key is kept secret. The need for sender and receiver to share secret learning is eliminated all communications involve only public keys, and no individual(a) key is ever transmitted or shared. No longer is it required to trust some communications channel to be secure against eavesdropping or betrayal. Anyone tail end send a confidential message just using public information, but it can only be decrypted with a tete-a-tete key that is in the sole possession of the intended recipient. Furthermore, public-key cryptography can be used for au consequentlytication (digital signatures) as well as for screen (encryption). Heres how it works for encryption when Alice wishes to send a message to Bob, she looks up Bobs public key in a directory, uses it to encrypt the mess age and sends it off. Bob then uses his private key to decrypt the message and read it. No one listening in can decrypt the message. Anyone can send an encrypted message to Bob but only Bob can read it. Clearly, one requirement is that no one can figure out the private key from the corresponding public key.Heres how it works for authentication Alice, to sign a message, does a computation involving both her private key and the message itself the output is called the digital signature and is attached to the message, which is then sent.