Patent US4596898A successfully refreshed from Google Patents.
US4596898A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for protecting stored and transmitted data from compromise or interception
Assignee: STATE BANK OF INDIA 460 PARK AVENUE NEW YORK NEW YORK 10022 A CORP
•
Filing: 1984-03-14
•
Granted: 1986-06-24
•
Expires: 2004-03-14
Abstract
Abstract Protection of transmitted and stored data from compromise or interception is achieved by a combined terminal authentication and encryption technique using a random number as part of both the encryption and authentication processes. Entry of data for transmission at a transmitting terminal automatically establishes a random number which is tranmitted ahead of the data stream along with a special fixed word and a code word which is encoded with the random number. The receiving station stores the random number and decodes the code word. The decoded code word and the received special word are compared to respective pre-stored counterparts thereof to determine authenticity of the transmitting terminal. Data encryption is effected by using three keys which depend, respectively, on data word content, data word sequence and the established random number.
Inventors
- 👤 Ramarao V. Pemmaraju
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:11
CPC Classifications
H; H04; H04L; H04L9/00; H04L9/06; H04L9/065; H04L2209/00; H04L2209/08; H04L2209/12
Claims Analysis
Total Claims: 65
Claim 1
Independent Claim
262 words
Apparatus for limiting access to and use of a data receiving terminal to one or more authorized data transmitting terminals, said apparatus comprising: at each authorized data transimitting terminal: means responisve to entry of data to be transmitted for establishing a plural bit random number; means for transmitting said random number to said data receiving terminal; word storage means for storing a plural bit predetermined transmitter word; means for transmitting said predetermined transmitter word to said data receiving terminal; code storage means for storing a plural bit transmitter code word; means for modifying said transmitter code word as a function of said random number to provide a plural bit modified transmitter code word, said means for modifying including means for determining the state of each bit in said modified transmitter code word on the basis of a comparison of the state of a corresponding bit in said transmitter code word with the state of a corresponding bit in said random number; and means for transmitting said modified transmitter code word to said data receiving terminal; at said data receiving terminal in response to receiving transmitted bits: means for receiving and storing the random number transmitted from a data transmitting terminal; means for receiving and storing the predetermined transmitter word transmitted from a data transmitting terminal; means for storing a plural bit predetermined receiver word; data path means for passing received data for processing; first comparator means for inhibiting passage of received data along said data path means unless the modified received word and the stored receiver code word have a predetermined relationship.
Claim 2
Dependent Claim
262 words
Apparatus for limiting access to and use of a data receiving terminal to one or more authorized data transmitting terminals, said apparatus comprising: at each authorized data transimitting terminal: means responisve to entry of data to be transmitted for establishing a plural bit random number; means for transmitting said random number to said data receiving terminal; word storage means for storing a plural bit predetermined transmitter word; means for transmitting said predetermined transmitter word to said data receiving terminal; code storage means for storing a plural bit transmitter code word; means for modifying said transmitter code word as a function of said random number to provide a plural bit modified transmitter code word, said means for modifying including means for determining the state of each bit in said modified transmitter code word on the basis of a comparison of the state of a corresponding bit in said transmitter code word with the state of a corresponding bit in said random number; and means for transmitting said modified transmitter code word to said data receiving terminal; at said data receiving terminal in response to receiving transmitted bits: means for receiving and storing the random number transmitted from a data transmitting terminal; means for receiving and storing the predetermined transmitter word transmitted from a data transmitting terminal; means for storing a plural bit predetermined receiver word; data path means for passing received data for processing; first comparator means for inhibiting passage of received data along said data path means unless the modified received word and the stored receiver code word have a predetermined relationship.
Claim 3
Dependent Claim
63 words
The apparatus according to claim 1 wherein said means for modifying said transmitter code word includes means for combining said transmitter code word and said random number in an exclusive OR function, and wherein said means for modifying said received transmitter code word includes means for combining said received transmitter code word and the stored received random number in an exclusive OR function.
Claim 4
Dependent Claim
26 words
The apparatus according to claim 1 wherein said first predetermined relationship corresponds to identity between the received predetermined transmitter word and the stored predetermined receiver word.
Claim 5
Dependent Claim
24 words
The apparatus according to claim 1 wherein said second predetermined relationship corresponds to identity between the modified received word and stored receiver code word.
Claim 6
Dependent Claim
322 words
Apparatus for limiting access to and use of a data receiving terminal to one or more authorized data transmitting terminals, said apparatus comprising: at each authorized data transmitting terminal: means responsive to entry of data to be transmitted for establishing a plural bit random number; means for transmitting said random number to said data receiving terminal; word storage means for sotring a plural bit predetermined transmitter word; means for transmitting said predetermined transmitter word to said data receiving terminal; code storage means for storing a plural bit transmitter code word; means for modifying said transmitter code word as a function of said random number to provide a modified transmitter code word; and means for transmitting said modified transmitter code word to said data receiving terminal; at said data receiving terminal, in response to receiving transmitted bits: means for receiving and storing the random number transmitted from a data transmitting terminal; means for receiving and storing the predetermined transmitter word transmitted from a data transmitting terminal; means for storing a plural bit predetermined receiver word; data path means for passing received data for processing; first comparator means for inhibiting passage of receivied data along said data path means unless the received predetermined transmitter word and the stored predetermined receiver word have a first predetermined relationship; means for storing a plural bit receiver code word; means for receiving the modified transmitter code word transmitted from a data transmitting terminal; means for modifying the received transmitter code word as a function of the stored receiver random number to provide a modified received word; and second comparator means for inhibiting passage or received data along said data path means unless the modified received word and the stored receiver code word have a predetermined relationship; wherein said predetermined transmitter word corresponds to a machine function character of the kind which is internally generated automatically at said data transmitter terminal for use in arranging data characters for processing.
Claim 7
Dependent Claim
322 words
Apparatus for limiting access to and use of a data receiving terminal to one or more authorized data transmitting terminals, said apparatus comprising: at each authorized data transmitting terminal: means responsive to entry of data to be transmitted for establishing a plural bit random number; means for transmitting said random number to said data receiving terminal; word storage means for sotring a plural bit predetermined transmitter word; means for transmitting said predetermined transmitter word to said data receiving terminal; code storage means for storing a plural bit transmitter code word; means for modifying said transmitter code word as a function of said random number to provide a modified transmitter code word; and means for transmitting said modified transmitter code word to said data receiving terminal; at said data receiving terminal, in response to receiving transmitted bits: means for receiving and storing the random number transmitted from a data transmitting terminal; means for receiving and storing the predetermined transmitter word transmitted from a data transmitting terminal; means for storing a plural bit predetermined receiver word; data path means for passing received data for processing; first comparator means for inhibiting passage of receivied data along said data path means unless the received predetermined transmitter word and the stored predetermined receiver word have a first predetermined relationship; means for storing a plural bit receiver code word; means for receiving the modified transmitter code word transmitted from a data transmitting terminal; means for modifying the received transmitter code word as a function of the stored receiver random number to provide a modified received word; and second comparator means for inhibiting passage or received data along said data path means unless the modified received word and the stored receiver code word have a predetermined relationship; wherein said predetermined transmitter word corresponds to a machine function character of the kind which is internally generated automatically at said data transmitter terminal for use in arranging data characters for processing.
Claim 8
Dependent Claim
94 words
The apparatus according to claim 1 further comprising: a first scrambler means located at each authorized data transmitting terminal for re-arranging the sequence of bits in said transmitter code word in a first predetermined manner, wherein said means for modifying the transmitter code word receives the transmitter code word in its re-arranged bit sequence; and second scrambler means located at said data receiver terminal for re-arranging the bit sequence of said receiver code word in said first predetermined manner, wherein said second comparator means receives the receiver code word in its re-arranged bit sequence.
Claim 9
Dependent Claim
122 words
The apparatus according to claim 6 further comprising: third scrambler means located at each authorized data transmitting terminal for re-arranging the original bit sequence of said established random number in a second predetermined manner, wherein said means for transmitting said random number transmits the random number in its re-arranged bit sequence, and wherein said means for modifying said transmitter code word receives said random number in its re-arranged bit sequence; and de-scrambler means located at said data receiving terminal for re-arranging the bit sequence of said stored received random number in a manner to restore the original bit sequence, and wherein said means for modifying the received code word receives the descrambled stored received random number in the restored original bit sequence.
Claim 10
Dependent Claim
122 words
The apparatus according to claim 1 further comprising: first scrambler means located at each authorized data transmitting terminal for re-arranging the original bit sequence of said established random number in a predetermined manner, wherein said means for transmitting said random number transmits the random number in its re-arranged bit sequence, and wherein said means for modifying said transmitter code word receives said random number in its re-arranged bit sequence; and de-scrambler means located at said data receiving terminal for re-arranging the bit sequence of said stored received random number in a manner to restore the original bit sequence, and wherein said means for modifying the received transmitter code word receives the descrambled stored received random number in the restored original bit sequence.
Claim 11
Dependent Claim
96 words
The apparatus according to claim 1 wherein each authorized data transmitting terminal includes encryption means operative subsequent to transmission of said predetermined data word, said random number, and said modified transmitter code word for successively transmitting, in encrypted form, data words which are entered in said data transmitting terminal; and wherein said data receiving terminal includes decryption means operative in response to said first and second predetermined relationships being detected at said first and second comparator means, respectively, for decrypting received data words and passing the decrypted data words along said data path means for processing.
Claim 12
Dependent Claim
51 words
The apparatus according to claim 9 wherein said encryption means comprises data modifying means for modifying each data word to be transmitted in accordance with a predetermined data-dependent function, and wherein said decryption means comprises further modifying means for modifying each received data word in accordance with said predetermined data-dependent function.
Claim 13
Dependent Claim
46 words
The apparatus according to claim 10 wherein said predetermined data-dependent function is an exclusive-OR function, wherein said data modifying means and said further modifying means each comprise means for combining certain bits of each data word with other bits in that word in respective exclusive-OR gates.
Claim 14
Dependent Claim
79 words
The apparatus according to claim 9 wherein said encryption means comprises first sequencer means for modifying each entered data word in accordance with a sequencing function which is dependent upon the position of that word in the sequence of entered data words, and wherein said decryption means comprises second sequencer means for modifying each received data word in accordance with a sequencing function which is dependent upon the position of that received word in the sequence of received data.
Claim 15
Dependent Claim
117 words
The apparatus according to claim 12 wherein said first sequencer means comprises: first counter means for providing a first plural bit count word which changes as each entered data word is transmitted to said data receiving terminal; and first gating means for modifying the bits in each data word as a function of corresponding bits in said first count word; and wherein said second sequencer means comprises: a second counter means for providing a second plural bit count word which changes as each received data word is received at said data receiving terminal; and second gating means for modifying the bits in each received data word as a function of corresponding bits in said second count word.
Claim 16
Dependent Claim
40 words
The apparatus according to claim 13 wherein said first and second gating means each includes a plurality of exclusive-OR gates, each arranged to receive a respective bit from said data word and a respective corresponding bit from said count word.
Claim 17
Dependent Claim
52 words
The apparatus according to claim 9 wherein said encryption means comprises randomizer means for modifying each data word to be transmitted as a function of the established random number; and wherein said decryption means comprises de-randomizer means for modifying each received data word as a function of the stored received random number.
Claim 18
Dependent Claim
61 words
The apparatus according to claim 15 wherein said randomizer means comprises means for combining certain bits of each data word with corresponding bits of said established random number in respective exclusive-OR gates; and wherein said de-randomizer means comprises means for combining certain bits in each received data word with corresponding bits of the stored received random number in respective exclusive-OR gates.
Claim 19
Dependent Claim
66 words
The apparatus according to claim 9 wherein said encryption means comprises means for modifying each entered data word to provide a modified word for transmission which is modified as a first function of the entered data word, as a second function of the position of the entered data word in the sequence of entered data words, and as a third function of the established random number.
Claim 20
Dependent Claim
33 words
The apparatus according to claim 17 wherein said decryption means comprises means for modifying each received data word to provide a decrypted word corresponding to a respective entered data word in unmodified format.
Claim 21
Dependent Claim
56 words
The apparatus according to claim 17 wherein said decryption means comprises means for decrypting each received modified word to provide an unmodified word devoid of said first function of the entered data word, said second function of the position of the entered data word in said sequence, and said third function of said established random number.
Claim 22
Dependent Claim
173 words
The apparatus according to claim 9 wherein each entered data word includes n bits, n being a positive integer at least equal to four, and wherein said encryption means provides a first encrypted data word and comprises x exclusive-OR gates, x being a positive integer between 1 and n-1, each exclusive-OR gate receiving a respective bit of said entered data word as a first input signal and at least one other bit of said data word as a second input signal, whereby the state of the output signal from each exclusive-OR gate is the same as or different from the state of its first input signal in accordance with the state of said other bit, wherein said first encrypted data word includes n bits made up of the output signals from said x exclusive-OR gates and n-x bits of said data word which do not serve as a first input signal for one of said x exclusive-OR gates, and wherein said at least one other bit corresponds to one of said n-x bits.
Claim 23
Dependent Claim
26 words
The apparatus according to claim 9 wherein said encryption means includes scrambler means for re-arranging the sequence of bits in each data word to be transmitted.
Claim 24
Dependent Claim
33 words
The apparatus according to claim 9 wherein said encryption means comprises means for varying the number of bits associated with each word transmitted from said data transmitting terminal to said data receiving terminal.
Claim 25
Independent Claim
354 words
A method for limiting access to and use of a data receiving terminal to one or more authorized transmitting terminals, said method comprising the steps of: at each authorized data transmitting terminal: in response to entry of data to be transmitted, establishing a plural bit random number; transmitting said random number to said data receiving terminal; storing a plural bit predetermined transmitted word; transmitting said predetermined transmitter word to said data receiving terminal; storing a plural bit transmitter code word; modifying said transmitter code word as a function of said random number to provide a modified transmitter code word; and transmitting said modified transmitter code word to said data receiving terminal; at said receiving terminal, in response to receiving transmitted signal bits: receiving and storing the random number transmitted from a data transmitting terminal; receiving and storing the predetermined transmitter word transmitted from a data transmitting terminal; storing a plural bit predetermined receiver word; inhibiting passage of received data bits for processing unless the received predetermined transmitter word and the stored predetermined receiver word have a first predetermined relationship; storing a plural bit receiver code word; receiving the modified transmitter code word transmitted from a data transmitting terminal; modifying the received transmitter code word as a function of the stored received random number to provide a modified received word; and inhibiting passage of received data bits for processing unless the modified received word and the stored receiver code word have a second predetermined relationship; and further comprising the steps of: re-arranged the original bit sequence of said established random number in a second predetermined manner, wherein said random number is transmitted in its re-arranged bit sequence, and wherein the step of modifying said transmitter code word invloves modifying the transmitter code word woth the random number in its re-arranged bit sequence; and re-arranging the bit sequence of said stored received random number at said data receiving terminal in a manner to restore the original bit sequence, wherein the step of modifying the received transmitter code word includes modifying the received tansmitter code word with the received random number in its restored original bit sequence.
Claim 26
Independent Claim
354 words
A method for limiting access to and use of a data receiving terminal to one or more authorized transmitting terminals, said method comprising the steps of: at each authorized data transmitting terminal: in response to entry of data to be transmitted, establishing a plural bit random number; transmitting said random number to said data receiving terminal; storing a plural bit predetermined transmitted word; transmitting said predetermined transmitter word to said data receiving terminal; storing a plural bit transmitter code word; modifying said transmitter code word as a function of said random number to provide a modified transmitter code word; and transmitting said modified transmitter code word to said data receiving terminal; at said receiving terminal, in response to receiving transmitted signal bits: receiving and storing the random number transmitted from a data transmitting terminal; receiving and storing the predetermined transmitter word transmitted from a data transmitting terminal; storing a plural bit predetermined receiver word; inhibiting passage of received data bits for processing unless the received predetermined transmitter word and the stored predetermined receiver word have a first predetermined relationship; storing a plural bit receiver code word; receiving the modified transmitter code word transmitted from a data transmitting terminal; modifying the received transmitter code word as a function of the stored received random number to provide a modified received word; and inhibiting passage of received data bits for processing unless the modified received word and the stored receiver code word have a second predetermined relationship; and further comprising the steps of: re-arranged the original bit sequence of said established random number in a second predetermined manner, wherein said random number is transmitted in its re-arranged bit sequence, and wherein the step of modifying said transmitter code word invloves modifying the transmitter code word woth the random number in its re-arranged bit sequence; and re-arranging the bit sequence of said stored received random number at said data receiving terminal in a manner to restore the original bit sequence, wherein the step of modifying the received transmitter code word includes modifying the received tansmitter code word with the received random number in its restored original bit sequence.
Claim 27
Independent Claim
139 words
A method for restricting access to a computer to only authorized data terminals, said method comprising the steps of: in response to entry of a plural bit data word into said terminal, providing three authentication words for identifying an authorized data terminal; and transmitting the entered data words to said computer in a transmission sequence with said three authentication words interposed in said sequence prior to all of the entered data words; wherein the step of generating includes the steps of: establishing a plural bit random number for said transmission sequence as one of said three authentication words; retrieving a stored fixed words as another of said authentication words; retrieving a code word; and modifying said code word as a function of said established random number to provide a modified code word as still another of said authentication words.
Claim 28
Independent Claim
139 words
A method for restricting access to a computer to only authorized data terminals, said method comprising the steps of: in response to entry of a plural bit data word into said terminal, providing three authentication words for identifying an authorized data terminal; and transmitting the entered data words to said computer in a transmission sequence with said three authentication words interposed in said sequence prior to all of the entered data words; wherein the step of generating includes the steps of: establishing a plural bit random number for said transmission sequence as one of said three authentication words; retrieving a stored fixed words as another of said authentication words; retrieving a code word; and modifying said code word as a function of said established random number to provide a modified code word as still another of said authentication words.
Claim 29
Dependent Claim
54 words
The method according to claim 24 wherein the step of transmitting includes the step of: modifying each entered data word before it is transmitted by changing or not the state of certain bits of the entered data word in accordance with the state of at least one other bit in the entered data word.
Claim 30
Dependent Claim
49 words
The method according to claim 25 wherein the step of transmitting includes the step of: modifying each entered data word before it is transmitted by changing bits, or not, in that word as a function of the position of that word in the sequence of entry of data words.
Claim 31
Dependent Claim
43 words
The method according to claim 26 wherein the step of transmitting includes the step of: modifying each entered data word before it is transmitted by changing bits, or not, in that word as a function of respective bits in said established random number.
Claim 32
Dependent Claim
43 words
The method according to claim 25 wherein the step of transmitting includes the step of: modifying each entered data word before it is transmitted by changing bits, or not, in that word as a function of respective bits in said established random number.
Claim 33
Dependent Claim
49 words
The method according to claim 24 wherein the step of transmitting includes the step of: modifying each entered data word before it is transmitted by changing bits, or not, in that word as a function of the position of that word in the sequence of entry of data words.
Claim 34
Dependent Claim
43 words
The method according to claim 29 wherein the step of transmitting includes the step of: modifying each entered data word before it is transmitted by changing bits, or not, in that word as a function of respective bits in said established random number.
Claim 35
Dependent Claim
43 words
The method according to claim 24 wherein the step of transmitting includes the step of: modifying each entered data word before it is transmitted by changing bits, or not, in that word as a function of respective bits in said established random number.
Claim 36
Independent Claim
277 words
A method for limiting access to and use of a data receiving terminal to one or more authorized transmitting terminals, said method comprising the steps of: at each authorized data transmitting terminal: in response to entry of data to be transmitted, establishing a plural bit random number; transmitting said random number to said data receiving terminal; storing a plural bit predetermined transmitter word; transmitting said predetermined transmitter word to said data receiving terminal; storing a plural bit transmitter code word; modifying said transmitter code word as a function of said random number to provide a plural bit modified transmitter code word in which the state of each bit is determined on the basis of a comparison of the state of a corresponding bit in said transmitter code word with the state of a corresponding bit in said random number; and transmitting said modified transmitter code word to said data receiving terminal; at said receiving terminal, in response to receiving transmitted signal bits: receiving and storing the random number transmitted from a data transmitting terminal; receiving and storing the predetermined transmitter word transmitted from a data transmitting terminal; storing a plural bit predetermined receiver word; processing unless the received predetermined transmitter word and the stored predetermined receiver word have a first predetermined relationship; storing a plural bit receiver code word; receiving the modified transmitter code word transmitted from a data transmitting terminal; modifying the received transmitter code word as a function of the stored received random number to provide a modified received word; and inhibiting passage of received data bits for processing unless the modified received word and the stored receiver code word have a second predetermined relationship.
Claim 37
Independent Claim
277 words
A method for limiting access to and use of a data receiving terminal to one or more authorized transmitting terminals, said method comprising the steps of: at each authorized data transmitting terminal: in response to entry of data to be transmitted, establishing a plural bit random number; transmitting said random number to said data receiving terminal; storing a plural bit predetermined transmitter word; transmitting said predetermined transmitter word to said data receiving terminal; storing a plural bit transmitter code word; modifying said transmitter code word as a function of said random number to provide a plural bit modified transmitter code word in which the state of each bit is determined on the basis of a comparison of the state of a corresponding bit in said transmitter code word with the state of a corresponding bit in said random number; and transmitting said modified transmitter code word to said data receiving terminal; at said receiving terminal, in response to receiving transmitted signal bits: receiving and storing the random number transmitted from a data transmitting terminal; receiving and storing the predetermined transmitter word transmitted from a data transmitting terminal; storing a plural bit predetermined receiver word; processing unless the received predetermined transmitter word and the stored predetermined receiver word have a first predetermined relationship; storing a plural bit receiver code word; receiving the modified transmitter code word transmitted from a data transmitting terminal; modifying the received transmitter code word as a function of the stored received random number to provide a modified received word; and inhibiting passage of received data bits for processing unless the modified received word and the stored receiver code word have a second predetermined relationship.
Claim 38
Dependent Claim
57 words
The method according to claim 32 wherein the step of modifying said transmitter code word includes combining said transmitter code word and said random number in an exclusive-OR function, and wherein the step of modifying said received transmitter code word includes combining said received transmitter code word and the stored received random number in an exclusive-OR function.
Claim 39
Dependent Claim
26 words
The method according to claim 31 wherein said first predetermined relationship corresponds to identity between the received predetermined transmitter word and the stored predetermined receiver word.
Claim 40
Dependent Claim
25 words
The method according to claim 32 wherein said second predetermined relationship corresponds to identity between the modified received word and the stored receiver code word.
Claim 41
Independent Claim
276 words
A method for limiting access to and use of a data receiving terminal to one or more autborized transmitting terminals, said method comprising the steps of: at each authorized data transmitting terminal: in response to entry of data to be transmitted, establishing a plural bit random number; transmitting said random number to said data receiving terminal; storing a plural bit predetermined transmitter word; transmitting said predetermined transmitter word to said data receiving terminal; storing a plural bit transmitter code word; modifying said transmitter code word as a function of said random number to provide a modified transmitter code word; and transmitting said modified transmitter code word to said data receiving terminal; at said receiving terminal, in response to receiving transmitted signal bits: receiving and storing the random number transmitted from a data transmitting terminal; receiving and storing the predetermined transmitter word transmitted form a data transmitting terminal; storing a plural bit predetermined receiver word; inhibiting passage of received data bits for processing unless the received predetermined transmitter word and the stored predetermined receiver word have a first predetermined relationship; storing a plural bit receiver code word; receiving the modified transmitter code word transmitted from a data transmitting terminal; modifying the received transmitter code word as a function of the stored received random number to provide a modified received word; and inhibiting passage of received data bits for processing unless the modified received word and the stored receiver code word have a second predetermined relationship; wherein said predetermined transmitter word corresponds to a machine function character of the kind which is internally generated automatically at a data transmitter terminal for use in arranging data characters for processing.
Claim 42
Independent Claim
276 words
A method for limiting access to and use of a data receiving terminal to one or more autborized transmitting terminals, said method comprising the steps of: at each authorized data transmitting terminal: in response to entry of data to be transmitted, establishing a plural bit random number; transmitting said random number to said data receiving terminal; storing a plural bit predetermined transmitter word; transmitting said predetermined transmitter word to said data receiving terminal; storing a plural bit transmitter code word; modifying said transmitter code word as a function of said random number to provide a modified transmitter code word; and transmitting said modified transmitter code word to said data receiving terminal; at said receiving terminal, in response to receiving transmitted signal bits: receiving and storing the random number transmitted from a data transmitting terminal; receiving and storing the predetermined transmitter word transmitted form a data transmitting terminal; storing a plural bit predetermined receiver word; inhibiting passage of received data bits for processing unless the received predetermined transmitter word and the stored predetermined receiver word have a first predetermined relationship; storing a plural bit receiver code word; receiving the modified transmitter code word transmitted from a data transmitting terminal; modifying the received transmitter code word as a function of the stored received random number to provide a modified received word; and inhibiting passage of received data bits for processing unless the modified received word and the stored receiver code word have a second predetermined relationship; wherein said predetermined transmitter word corresponds to a machine function character of the kind which is internally generated automatically at a data transmitter terminal for use in arranging data characters for processing.
Claim 43
Dependent Claim
90 words
The method according to claim 32 further comprising the steps of: re-arranging the sequence of bits in said transmitter code word in a first predetermined manner, wherein the step of modifying the transmitter code word involves modifying the transmitter code word in its re-arranged bit sequence; and re-arranging the bit sequence of said receiver code word in said first predetermined manner, wherein the step of inhibiting unless said second predetermined relationship is detected involves comparison of the modified received word with the receiver code word in its re-arranged bit sequence.
Claim 44
Dependent Claim
115 words
The method according to claim 37 further comprising the steps of: re-arranging the original bit sequence of said established random number in a second predetermined manner, wherein said random number is transmitted in its re-arranged bit sequence, and wherein the step of modifying said transmitter code word involves modifying the transmitter code word with the random number in its re-arranged bit sequence; and re-arranging the bit sequence of said stored received random number at said data receiving terminal in a manner to restore the original bit sequence, wherein the step of modifying the received transmitter code word includes modifying the received transmitter code word with the received random number in its restored original bit sequence.
Claim 45
Dependent Claim
83 words
The apparatus according to claim 32 further comprising the steps of: at each data transmitting terminal, in response to transmission of said predetermined data word, said random number and said modified transmitter code word to said data receiving terminal, successively transmitting, in encrypted form, data words which are entered into said data transmitting terminal; and, at said data receiving terminal, in response to detection of said first and second predetermined relationships, decrypting received data words and passing the decrypted data words for processing.
Claim 46
Dependent Claim
50 words
The method according to claim 39 wherein the step of transmitting in encrypted form includes modifying each data word to be transmitted in accordance with a predetermined data dependent function, and wherein the step of decryption comprises modifying each received data word in accordance with said predetermined data dependent function.
Claim 47
Dependent Claim
81 words
The method according to claim 40 wherein said predetermined data dependent function is an exclusive-OR function, wherein the step of modifying each data word to be transmitted includes the step of combining certain bits of each such data word with other bits of that word in respective exclusive-OR functions, and wherein the step of modifying each received data word includes the step of combining certain bits of each received data word with other bits of that word in respective exclusive-OR functions.
Claim 48
Dependent Claim
83 words
The method according to claim 39 wherein the step of transmitting in encrypted form includes the step of modifying each entered data word in accordance with a sequencing function which is dependent upon the position of that word in the sequence of entered data words, and wherein the step of decryption includes the step of modifying each received data word in accordance with a sequencing function which is dependent upon the position of that received data word in the sequence of received data.
Claim 49
Dependent Claim
114 words
The method according to claim 42 wherein the step of modifying each entered data word includes the step of providing a first plural bit count word which changes as each entered data word is transmitted to said data receiving terminal; and modifying the bits in each data word as a function of corresponding bits in said first count word; and wherein the step of modifying each received data word includes the steps of: providing a second plural bit count word which changes as each received data word is received at said data receiving terminal; and modifying the bits in each received data word as a function of corresponding bits in the second count word.
Claim 50
Dependent Claim
51 words
The method according to claim 39 wherein the step of transmitting in encrypted form comprises modifying each data word to be transmitted as a function of the established random number, and wherein said step of decryption comprises modifying each received data word as a function of the stored received random number.
Claim 51
Dependent Claim
70 words
The method according to claim 39 wherein said step of transmitting in encrypted form comprises modifying each entered data word to provide a modified word for transmission which is modified as a first function of the bits in the entered data word, as a second function of the position of the entered data word in the sequence of entered data words, and a third function of the established random number.
Claim 52
Dependent Claim
32 words
The method according to claim 45 wherein said step of decrypting comprises modifying each received data word to provide a decrypted word corresponding to a respective entered data word in unmodified format.
Claim 53
Dependent Claim
56 words
The method according to claim 45 wherein said step of decrypting comprises decrypting each received modified data word to provide an unmodified word devoid of said first function of the entered data word, said second function of the position of the entered data word in said sequence, and said third function of said established random number.
Claim 54
Independent Claim
203 words
A method for use in conjunction with a computer system to determine whether or not encrypted data is received from an authorized transmitting terminal, and to decrypt encrypted data received from an authorized terminal, said method comprising the steps of: in response to reception of a stream of bits, separating a predetermined number of bits at the beginning of said stream from the remainder of said stream; segmenting said predetermined number of bits into three terminal authentication words, namely: a received random number word, a received fixed word, and a received code word; comparing said received fixed word to a pre-stored fixed word and inhibiting acceptance of the remainder of said bit stream if the received and pre-stored fixed words do not have a first predetermined relationship; modifying the received code word as a predetermined function of the received random number word to provide a modified code word; comparing said modified code word to a pre-stored word and inhibiting acceptance of the remainder of said bit stream if the modified and pre-stored code words do not have a second predetermined relationship; in response to detecting both said first and second predetermined relationships, decrypting data words which comprise the remainder of said bit stream.
Claim 55
Independent Claim
203 words
A method for use in conjunction with a computer system to determine whether or not encrypted data is received from an authorized transmitting terminal, and to decrypt encrypted data received from an authorized terminal, said method comprising the steps of: in response to reception of a stream of bits, separating a predetermined number of bits at the beginning of said stream from the remainder of said stream; segmenting said predetermined number of bits into three terminal authentication words, namely: a received random number word, a received fixed word, and a received code word; comparing said received fixed word to a pre-stored fixed word and inhibiting acceptance of the remainder of said bit stream if the received and pre-stored fixed words do not have a first predetermined relationship; modifying the received code word as a predetermined function of the received random number word to provide a modified code word; comparing said modified code word to a pre-stored word and inhibiting acceptance of the remainder of said bit stream if the modified and pre-stored code words do not have a second predetermined relationship; in response to detecting both said first and second predetermined relationships, decrypting data words which comprise the remainder of said bit stream.
Claim 56
Dependent Claim
36 words
The method according to claim 48 wherein the step of decrypting includes: modifying each received data word by changing bits, or not, in that word as a function of respective bits in said received random word.
Claim 57
Dependent Claim
41 words
The method according to claim 49 wherein the step of decrypting includes: modifying each received data word by changing bits, or not, in that word as a function of the position of that word in the sequence of received data words.
Claim 58
Dependent Claim
40 words
The method according to claim 50 wherein the step of decrypting includes: modifying each received data word by changing certain bits, or not, in that word in accordance with the state of at least one other bit in that word.
Claim 59
Dependent Claim
40 words
The method according to claim 49 wherein the step of decrypting includes: modifying each received data word by changing certain bits, or not, in that word in accordance with the state of at least one other bit in that word.
Claim 60
Dependent Claim
41 words
The method according to claim 48 wherein the step of decrypting includes: modifying each received data word by changing bits, or not, in that word as a function of the position of that word in the sequence of received data words.
Claim 61
Dependent Claim
40 words
The method according to claim 48 wherein the step of decrypting includes: modifying each received data word by changing certain bits, or not, in that word in accordance with the state of at least one other bit in that word.
Claim 62
Dependent Claim
79 words
Apparatus for encrypting plural bit data words entered into said apparatus in sequence, said apparatus comprising: means for modifying bits in each entered word as a function of the state of at least one other bit in that data word; means for modifying bits in each entered data word as a function of the position of that word in said sequence; and means for modifying bits in each entered data word as a function of a randomly selected word.
Claim 63
Dependent Claim
79 words
Apparatus for encrypting plural bit data words entered into said apparatus in sequence, said apparatus comprising: means for modifying bits in each entered word as a function of the state of at least one other bit in that data word; means for modifying bits in each entered data word as a function of the position of that word in said sequence; and means for modifying bits in each entered data word as a function of a randomly selected word.
Claim 64
Independent Claim
81 words
A method for encrypting plural bit data words which are entered into a terminal in a sequence, said method comprising the steps of: modifying bits in each entered data word as a function of the state of at least one other bit in that data word; modifying bits in each entered data word as a function of the position of that word in said sequence; and modifying bits in each entered data word as a function of a randomly selected word.
Claim 65
Independent Claim
81 words
A method for encrypting plural bit data words which are entered into a terminal in a sequence, said method comprising the steps of: modifying bits in each entered data word as a function of the state of at least one other bit in that data word; modifying bits in each entered data word as a function of the position of that word in said sequence; and modifying bits in each entered data word as a function of a randomly selected word.
References Cited (Backward Citations)
US3657521A
Cited
US4208575A
Cited
US4186871A
Cited
US4431865A
Cited
US4328414A
Cited
US4465153A
Cited
US4447672A
Cited
US4464678A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-06-23 | 1989-12-23 | 1990-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-23 | 1993-12-23 | 1994-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-23 | 1997-12-23 | 1998-06-24 | $7700.00 | Window Closed / Lapsed |