Prev | Current Page 466 | Next

Carl Reynolds and Paul Tymann

"Schaum's Outline of Principles of Computer Science"


?—? Collect only data that is required.
?—? Insure the accuracy of data.
?—? Provide a means for individuals to review data about themselves for accuracy.
?—? Provide a means for correction of inaccurate data.
?—? Protect against ???secondary use??? of data.
ENCRYPTION
Related to the question of privacy is encryption. In an effort to keep communications secure from eavesdropping,
people encrypt their communications. Before 1976, if one wanted to encrypt communications, one probably
used a single key, or symmetrical encryption, mechanism. Each user knew the key, and each user encrypted their
messages with the key, and decrypted incoming messages using the same key. The problem with this method is
that all users had to share in advance the secret of the key. Passing the single key around to all users created
risks of discovery for all.
In 1976 Diffie and Hellman published an asymmetric key cryptosystem. It and several related mechanisms
became known as public key encryption. In this system, each user has a pair of keys, one of which the user
publishes and is therefore public, and one of which the user keeps secret only to themselves. If Joe wants to
send Mary a secret message, Joe encrypts the message using Mary??™s public key.


Pages:
454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478
tanie noclegi mielno asus netbooki Chirurg łódź Namioty Mazury i interesująca cena Szkoły policealne fryzjer w warszawie