Passwordless secure and efficient remote data update
 Secure communication is effected when computers A and B that are interconnected by an insecure medium employ a dataset that is known to both and that is otherwise used within one or other of the computers for other than effecting secure communication as the shared secret from which an encryption key is derived. A dataset that needs to be securely communicated from computer A to computer B is encrypted with an encryption key derived from the shared secret. Computer B derives its own key and decrypts the received communication. In an enhanced version of this method, information is included in the transmission which assures computer B that no alterations occurred during transmission. When the dataset that needs to be securely communicated by computer A to computer B is an updated version of a dataset that already is present in computer B, a further enhancement suggests that computer A transmit only the difference between original dataset and the updated dataset. A benefit accrues when the dataset that is updated is also the dataset that is used as the shared secret, because the shared secret is changed with each update. In a still further modification, the shared secret is altered arbitrarily with each transmission in a manner that is unrelated to any specific function for which the shared secret dataset may be employed. 
AT&T Corp.
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inventional inventional
Kiem-Phong
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