EP0387599A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of encrypting transmitted data using a unique key
Assignee: Tandem Computers Inc
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Filing: 1990-02-27
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Granted: —
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Expires: 2010-02-27
Abstract
Abstract A method of encrypting data for on-line data communication between a host computer and each of a plurality of remote terminals, wherein a unique dynamic key is periodically generated for each said terminal using a system seed key residing only in the host computer, said dynamic key being for use by said terminal in encrypting data transmitted to said host computer and for decrypting data received from said host computer, each said terminal further including means for storing a previously generated dynamic key for said terminal, comprising the following steps: a. receiving at said host computer a new dynamic key request from one of said terminals, said new dynamic key request including a predetermined terminal identifier for said terminal; b. determining in said host computer the dynamic key previously generated for said terminal by said host wherein said dynamic key previously generated by said host is currently stored in said terminal; c. generating in said host computer a new dynamic key for said terminal as a function of said seed key and said predetermined terminal identifier for said terminal; d. encrypting said new dynamic key in said host computer using said dynamic key previously generated by said host computer; e. transmitting said encrypted new dynamic key from said host computer to said terminal; f. decrypting said new dynamic key at said terminal using said dynamic key previously generated by said host currently stored in said terminal.
Inventors
- 👤 Martin M. Atalla
- 👤 Webster D. Hopkins
- 👤 Ralph R. Bestock
- 👤 Jae-Young Kim
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 23:18
CPC Classifications
H; H04; H04L; H04L63/00; H04L63/06; G; G06; G06Q; G06Q20/00; G06Q20/38; G06Q20/382; G06Q20/3829; G07; G07F; G07F7/00; G07F7/08; G07F7/10; G07F7/1016; H04L63/08; H04L63/083; H04L9/00; H04L9/08; H04L9/0816; H04L9/0819; H04L9/0822; H04L9/0891; H04L2209/00; H04L2209/56
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
238 words
A method of encrypting data for on-line data communication between a host computer and each of a plurality of remote terminals, wherein a unique dynamic key is periodically generated for each said terminal using a system seed key residing only in the host computer, said dynamic key being for use by said terminal in encrypting data transmitted to said host computer and for decrypting data received from said host computer, each said terminal further including means for storing a previously generated dynamic key for said terminal, said method comprising the steps of: a. receiving at said host computer a new dynamic key request from one of said terminals, said new dynamic key request including a predetermined terminal identifier for said terminal; b. determining in said host computer the dynamic key previously generated for said terminal by said host wherein said dynamic key previously generated by said host is currently stored in said terminal; c. generating in said host computer a new dynamic key for said terminal as a function of said seed key and said predetermined terminal identifier for said terminal; d. encrypting said new dynamic key in said host computer using said dynamic key previously generated by said host computer; e. transmitting said encrypted new dynamic key from said host computer to said terminal; f. decrypting said new dynamic key at said terminal using said dynamic key previously generated by said host currently stored in said terminal;
Claim 2
Independent Claim
238 words
A method of encrypting data for on-line data communication between a host computer and each of a plurality of remote terminals, wherein a unique dynamic key is periodically generated for each said terminal using a system seed key residing only in the host computer, said dynamic key being for use by said terminal in encrypting data transmitted to said host computer and for decrypting data received from said host computer, each said terminal further including means for storing a previously generated dynamic key for said terminal, said method comprising the steps of: a. receiving at said host computer a new dynamic key request from one of said terminals, said new dynamic key request including a predetermined terminal identifier for said terminal; b. determining in said host computer the dynamic key previously generated for said terminal by said host wherein said dynamic key previously generated by said host is currently stored in said terminal; c. generating in said host computer a new dynamic key for said terminal as a function of said seed key and said predetermined terminal identifier for said terminal; d. encrypting said new dynamic key in said host computer using said dynamic key previously generated by said host computer; e. transmitting said encrypted new dynamic key from said host computer to said terminal; f. decrypting said new dynamic key at said terminal using said dynamic key previously generated by said host currently stored in said terminal;
Claim 3
Dependent Claim
60 words
The method of claim 1, characterized by g. encrypting data at said terminal using said new dynamic key and transmitting said encrypted data to said host; h. decrypting said encrypted data at said host using said new dynamic key; and i. storing said new dynamic key in said terminal in place of said dynamic key previously generated by said host.
Claim 4
Dependent Claim
67 words
The method of claim 1 or 2, characterized in that at said host computer and said terminal a plurality of transaction data encryption keys using a plurality of variants is generated, that said plurality of variants are common to said host system and said terminal, and that said plurality of variants generates said plurality of transaction data encryption keys as a function of said new dynamic key.
Claim 5
Dependent Claim
19 words
The method of claim 2 or 3, characterized in that steps a. to i. are repeated for each transaction.
Claim 6
Dependent Claim
20 words
The method of claim 3 or 4, characterized in that steps a. to i. are selectively repeated at predetermined intervals.
Claim 7
Independent Claim
30 words
The method of one of claims 3 to 5, characterized in that one of said plurality of trans action encryption keys is used to encrypt said data at said terminal.
Claim 8
Independent Claim
24 words
The method of one of the preceding claims, characterized in that said new dynamic key request further includes a transaction number for said terminal.
Claim 9
Dependent Claim
39 words
The method of claim 7, characterized in that said new dynamic key is generated by said host as a function of said seed key and said predetermined terminal identifier for said terminal, and said transaction number for said terminal.
Claim 10
Independent Claim
27 words
The method of one of the preceding claims, characterized in that said host computer and said plurality of terminals comprises a card activation and pin selection system.
Claim 11
Independent Claim
30 words
The method of one of the preceding claims, characterized in that said host computer and said plurality of terminals comprises an Electronic Funds Transfer System with Point of Sale Terminals.
Claim 12
Independent Claim
24 words
The method of one of the preceding claims, characterized in that said host computer and said plurality of terminals comprises an Automated Teller Network.
Claim 13
Independent Claim
23 words
The method of one of the preceding claims, characterized in that said dynamic key is comprised of a 64 bit data input string.
Claim 14
Independent Claim
26 words
The method of one of the preceding claims, characterized in that one or more addi tional seed keys are provided to generate said new dynamic key.
Claim 15
Dependent Claim
23 words
The method of claim 13, characterized in that each of said seed keys is selectively variable through input means of the host computer.
Claim 16
Dependent Claim
31 words
The method of claim 3, characterized in that transaction data transmitted between said host computer and said one of said plurality of terminals is encrypted with said transaction data encryption keys.
Claim 17
Dependent Claim
25 words
The method of claim 15, characterized in that said transaction data encryption keys include at least a key encryption key and a PIN encryption key.
Claim 18
Dependent Claim
38 words
The method of claim 16, characterized in that said variant generating means includes a plurality of variant numbers, each of said plurality of variant numbers corresponding to one of each of said plurality of transaction data encryption keys.
Claim 19
Dependent Claim
41 words
The method of claim 17, characterized in that said variant generating means includes means for exclusively or-ing each of said plurality of variant numbers with said first dynamic key wherein each of said corresponding plurality of transaction data keys is formed.
Claim 20
Dependent Claim
57 words
The method of claim 18, characterized in that said variant numbers are comprised of a 4 bit data input and wherein said means for exclusively or-ing said said variant numbers with said first dynamic key exclusively or's said 4 bit input with a selected 4 bits in the first 8 bits of said dynamic key input string.
Claim 21
Independent Claim
299 words
A method for safeguarding the on-line transmission of data between a host computer and any one of a plurality of remote terminals, particularly according to one of the preceding claims, wherein a unique encryption key is used for each transmission of data between said host computer and said one of said plurality of terminals, said unique encryption key being derived as function of a unique dynamic key generated using a system seed key residing only in said host computer wherein a plurality of unique dynamic keys may be generated as a function of said seed key, and wherein N is a finite integer greater than or equal to 1 that defines the number of unique dynamic keys generated as a function of said seed key, said generation of said unique dynamic keys being programmable to occur at preselected intervals, and wherein the following steps are provided: a. generating in said host computer an nth dynamic key for said one of said plurality of terminals, wherein said nth dynamic key is a function of said seed key and a predetermined terminal identifier for said one of said plurality of terminals; b. encrypting said nth dynamic key in said host computer using the (n-1)th dynamic key, wherein said (n-1)th dynamic key is also stored at said one of said plurality of terminals; c. transmitting said encrypted nth dynamic key from said host computer to said one of said plurality of terminals; d. decrypting said nth dynamic key at said terminal using said (n-1)th dynamic key stored at said one of said plurality of terminals; e. encrypting data at said one of said plurality of terminals using said nth dynamic key and transmitting said encrypted data to said host; f. decrypting said encrypted data at said host using said nth dynamic key.
Claim 22
Dependent Claim
165 words
A method according to the first part of claim 1, characterized by a. sending a new dynamic key request to said host computer, said new dynamic key request comprising at least a terminal identification number for said terminal and a terminal transaction number for said terminal; b. receiving from said host computer an encrypted new dynamic key, wherein said new dynamic key is generated as a function of said new dynamic key request and said new dynamic key is encrypted by said host with a previously generated dynamic key; c. decrypting said new dynamic key at said terminal using said dynamic key previously generated by said host currently stored in said terminal; d. encrypting data at said terminal using said new dynamic key and transmitting said encrypted data to said host; e. decrypting said encrypted data at said host using said new dynamic key; and f. storing said new dynamic key in said terminal in place of said dynamic key previously generated by said host.
References Cited (Backward Citations)
No citation records indexed.
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