Secure file transfer system and method
First Claim
1. A file transfer system consisting ofa plurality of computers connected by a communications channel,means for generating or retrieving random numbers in each of said computers,means for digital handshaking between said computers to establish communications,means for sending frames and data blocks through said channel, reliably and efficiently,means for transmitting an encryption initialization vector frame in order to synchronize cipher feedback,means for deriving a secure session key in each of said computers, based on said random numbers and on exchanged derived numbers,means for encrypting data blocks using said cipher feedback,means for detecting transmission errors,means for resending variants of said encryption initialization vector frame and said frames and data blocks in case of said transmission errors,means for sending an encrypted copy of a file or files based on said session key,means for receiving said encrypted copy of said file or files, andmeans for decrypting said received copy of said file or files.
0 Assignments
0 Petitions
Accused Products
Abstract
This invention is a system and method for securely and robustly transferring a file from one computer to another without having a prearranged encryption key. Data is transferred by first generating some random numbers on each computer and undertaking some cryptographically secure handshaking in which a session key is determined. Then the file is broken up into blocks and encrypted with a chaining block cipher and transmitted. The blocks have headers which identify the them, and allow for detection and correction of transmission errors. Before retransmitting a block, an initialization vector is sent to synchronize the cipher modules. The random numbers are generated with keystroke timings combined with a pseudorandom number generator to expand the supply.
-
Citations
20 Claims
-
1. A file transfer system consisting of
a plurality of computers connected by a communications channel, means for generating or retrieving random numbers in each of said computers, means for digital handshaking between said computers to establish communications, means for sending frames and data blocks through said channel, reliably and efficiently, means for transmitting an encryption initialization vector frame in order to synchronize cipher feedback, means for deriving a secure session key in each of said computers, based on said random numbers and on exchanged derived numbers, means for encrypting data blocks using said cipher feedback, means for detecting transmission errors, means for resending variants of said encryption initialization vector frame and said frames and data blocks in case of said transmission errors, means for sending an encrypted copy of a file or files based on said session key, means for receiving said encrypted copy of said file or files, and means for decrypting said received copy of said file or files.
-
11. A file transfer method consisting of
connecting a plurality of computers by a communications channel, generating or retrieving random numbers in each said computer, digital handshaking between said computers to establish communications, sending frames and data blocks through said channel, reliably and efficiently, transmitting an encryption initialization vector frame in order to synchronize cipher feedback, deriving a secure session key in each of said computers, based on said random numbers and on exchanged derived numbers, encrypting data blocks using said cipher feedback, detecting transmission errors, resending variants of said encryption initialization vector frame and said frames and data blocks in case of said transmission errors, sending an encrypted copy of a file or files based on said session key, receiving said encrypted copy of said file or files, and decrypting said received copy of said file or files.
Specification