System and method for delivering and examining digital tickets

• US 7,093,130 B1
• Filed: 01/24/2000
• Issued: 08/15/2006
• Est. Priority Date: 01/24/2000
• Status: Expired due to Term

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Kobayashi, Noriya, Yee, Bennet
• Primary Examiner(s): Zand, Kambiz
• Application Number:
  US09/490,354
• Time in Patent Office: 2,395 Days
• Field of Search: 713/176, 705/50, 705/69
• US Class Current: 713/176
• CPC Class Codes: G06F 21/64 Protecting data integrity, e.g. using checksums, certificates or signatures
• CPC Class Codes: G06Q 20/3674 involving authentication
• CPC Class Codes: G06Q 20/3821 Electronic credentials
• CPC Class Codes: G06Q 30/06 Buying, selling or leasing transactions
• CPC Class Codes: G07B 15/00 Arrangements or apparatus for collecting fares, tolls or entrance fees at one or more control points handling coins or valuable papers, e.g. banknotes, G07D; apparatus for vending or hiring articles or services activated by coins, credit cards, paper currency or the like G07F7/00, G07F17/00
• CPC Class Codes: H04L 2209/42 Anonymization, e.g. involving pseudonyms
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 63/12 Applying verification of the received information cryptographic mechanisms or cryptographic arrangements for data integrity or data verification H04L9/32
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions
• CPC Class Codes: H04L 9/3247 involving digital signatures

Abstract

A digital ticket is procured by a client ticket consumer upon, preferably, the Internet from and by staged interaction with a ticket provider server. The digital ticket becomes embodied in a tangible transportable data storage medium, normally a 2-D bar code printed on paper by the consumer, or on the consumer'"'"'s flexible disk or smart card, containing Sign(s,I||hash(R))||R where (1) R is a number having its origin in the computer of the ticket consumer, which number R is appended to (2) a number Sign(s,I||hash(R)). This number Sign(s,I||hash(R)) was earlier computed in the computer of the ticket provider as a digital signature using signature key s of a number hash(R) combined with event information I, and was subsequently communicated across the communications network to the computer of the ticket consumer. The number hash(R) was itself even earlier computed in the computer of the ticket consumer as a one-way function of random number R, which computed one-way function was subsequently communicated to the computer of the ticket provider. The number R is private to the ticket consumer and not public; the digital signature key s is private to the ticket provider.

The digital ticket is redeemed by (1) transporting the transportable storage medium within which the Sign(s,I||hash(R))||R is written to the particular selected event; (2) tendering the digital ticket for verification and for admission; (3) reading the Sign(s,I||hash(R))||R to an event computer and extracting the number R; (4) decrypting the remaining Sign(s, I||hash(R)) with verification key v of the ticket producer to get hash(R) and I; (5) re-calculating from R, with the same one-way function previously used, a re-calculated hash(R); then, having this recalculated hash(R) to hand; (6) comparing the re-calculated hash(R) to the extracted hash(R). The (4) decrypting will work, producing a proper I for the selected event, and the (6) comparing will be equal, only for a legitimate ticket.

Claims

1. A computerized method for delivering a digital ticket from a ticket provider to a ticket consumer across a communications channel, the method comprising:

first communicating, across a communications channel from a computer of a ticket provider to a computer of the ticket consumer, first digital data D₁ in respect of an occurrence relating to the ticket; and

second communicating, across the communications channel from the computer of the ticket consumer to the computer of the ticket provider, second digital data D₂ relating to purchase of the ticket; and

calculating in the computer of the ticket provider by use of a private key s a digital signature of third digital data D₃, which third digital data D₃ is in respect of one or both of the first digital data D₁ and the second digital data D₂, and which digital signature of the digital data D₃ is as well, being a proof both (i) that a private signature key s was used by the computer of the ticket provider in generation of the digital signature and (ii) that one or both of the digital data D₁, D₂ was used in respect of its generation, (iii) suitably stored in a transportable storage medium; and

wherein the digital data D₁, D₂ in respect of which the digital signature of digital data D₃ was generated becomes a memorialization of a particular provision by the ticket provider of the particular digital ticket for the particular occurrence to the ticket consumer who is particularly identified at least as a party at the other end of the communicating transpiring across the communications channel; and

third communicating, across the communications channel from the computer of the ticket provider to the computer of the ticket consumer, at least the signed digital data D₃; and

first storing with the computer of the ticket consumer in the transportable storage medium at least the signed digital data D₃, thus turning the transportable storage medium into a digital ticket; and

physically transporting the digital ticket in the form of the transportable storage medium so containing at least the signed digital data D₃, to a specific place for the occurrence relating to the ticket; and

tendering the digital ticket for redemption to a ticket taker at the specific place; and

reading into a computer of the ticket taker at least the signed digital data D₃; and

recovering in the computer of the ticket taker, with a digital verification key v corresponding to the signature key s of the ticket provider and from the signed digital data D₃, the digital data D₃; and

determining in the computer of the ticket taker IF the digital data D₃ was recoverable by verification key v AND, having been so recovered, the digital data D₃ correctly memorializes the particular provision by the ticket provider of the particular third digital data D₃ for the particular occurrence to the particular ticket consumer who at one time communicated across the communications channel THEN the digital ticket is valid, ELSE IF the digital data D₃ was recovered by use of the verification key v BUT the digital data D₃ recovered incorrectly memorializes the particular provision by the ticket provider of the particular third digital data D₃ for the particular occurrence to the particular ticket consumer who at one time communicated across the communications channel THEN the digital ticket is invalid;

wherein the second communicating is of second digital data D₂ including a one-way function hash (R) of a number R which number R is uniquely known to the computer of the ticket consumer and not to the computer of the ticket provider.

2. The digital ticket computerized delivery and redemption method according to claim 1

wherein the calculating in the computer of the ticket provider is of a digital signature in respect of the third digital data D₃ including the one way function of hash (R) plus information I concerning the event for which the ticket is had, Sign (s, I||hash (R));

wherein the third communicating is of Sign (s, I||hash (R));

wherein the first storing is of R appended to Sign (s, I||hash (R)), or Sign (s, I||hash (R))||R, as the digital ticket;

wherein the reading into the computer of the ticket taker is of the Sign (s, I||hash (R))||R;

wherein the recovering in the computer of the ticket taker of the I||hash (R) gives hash (R); and

, having both R and hash (R) to hand,

wherein the determining further proceeds by recalculating the hash (R) in respect of R, so that IF the recalculated hash (R) equals to the recovered hash (R) of the digital ticket as read THEN the digital ticket is valid ELSE IF the hash (R) does not equal to the recovered hash (R) of the digital ticket as read THEN the digital ticket is invalid.

3. The digital ticket computerized delivery and redemption method according to claim 2

wherein the determining still further proceeds so that IF the read digital ticket is the first uniquely presented THEN the digital ticket is valid ELSE IF the read digital ticket is not the first uniquely presented THEN the digital ticket is invalid.

4. The digital ticket computerized delivery and redemption method according to claim 2

wherein the second communicating is of a one-way hash function hash (R) of a number R;

wherein the calculating in the computer of the ticket provider is of a digital signature in respect of signature key s of both the hash (R) plus information I concerning the event for which the ticket is had, Sign (s, I||hash(R));

wherein the third communicating is of Sign (s, I||hash (R));

wherein the first storing is of R appended to Sign (s, I||hash (R)), or Sign (s, I||hash (R))||R, as the digital ticket;

wherein the reading into the computer of the ticket taker is of the Sign (s, I||hash (R))||R;

wherein the recovering in the computer of the ticket taker of the I||hash (R) gives hash (R); and

, having both R and hash (R) to hand,

wherein the determining further proceeds by recalculating the hash (R) in respect of R, so that IF the recalculated hash (R) equals to the recovered hash (R) of the digital ticket as read THEN the digital ticket is valid ELSE IF the hash (R) does not equal to the recovered hash (R) of the digital ticket as read THEN the digital ticket is invalid.

5. The digital ticket computerized delivery and redemption method according to claim 4

wherein the determining still further proceeds so that IF the read digital ticket is the first uniquely presented THEN the digital ticket is valid ELSE IF the read digital ticket is not the first uniquely presented THEN the digital ticket is invalid.

6. The digital ticket computerized delivery and redemption method according to claim 1

wherein the calculating is of digital signature suitably displayed as a 2-D code;

and

wherein the first storing with the computer of the ticket consumer is by printing of the 2-D code upon a printable transportable storage medium.

7. The digital ticket computerized delivery and redemption method according to claim 6 wherein the reading into a computer of the ticket taker of the digital signature transpires by use of an optical reader.

8. A computerized method for delivery of a ticket from a ticket provider to a ticket consumer across a communications channel, the method comprising:

first transmitting, across a communications channel from a computer of a ticket provider to a computer of a ticket consumer, data regarding an event relating to the ticket;

first calculating in the computer of the ticket consumer a number R;

then

second calculating in the computer of the ticket consumer a one-way function of the number R as hash (R);

second transmitting, across the communications channel from the computer of the ticket consumer to the computer of the ticket provider, at least the hash (R) as ticket order data;

third calculating in the computer of the ticket provider in respect of signature key s a digital signature of hash (R) appended to information I regarding the event as Sign (s, I||hash (R)), this Sign (s, I||hash (R)) constituting a digital ticket precursor;

then

third transmitting, across the communications channel from the computer of the ticket provider to the computer of the ticket consumer, the digital ticket precursor Sign (s, I||hash (R));

fourth calculating, in the computer of the ticket consumer as an appending of R to the digital ticket precursor Sign (s, I||hash (R)), Sign (s, I||hash (R))||R, as a digital ticket;

first storing the digital ticket Sign (s, I||hash (R))||R from the computer of the ticket consumer to a transportable storage medium.

9. The method according to claim 8 expanded and extended to use of the digital ticket by the ticket consumer at the particular event, the method, after the first storing, further comprising:

transporting the transportable storage medium within which the digital ticket Sign (s, I||hash (R))||R is written to the particular event;

tendering the digital ticket within the transportable storage medium for verification and for admission to the particular event;

reading the digital ticket Sign (s, I||hash (R))||R to an event computer;

extracting in the event computer the number R from the read Sign (s, I||hash (R))||R;

fifth calculating, by use of a verification key v complimentary to the signature key s, I||hash (R);

plus

sixth calculating in the event computer, with the same one-way function previously used in the second calculating, hash (R); and

then, having both R and sixth-calculated hash (R) to hand,

comparing the sixth-calculated hash (R) to the hash (R) portion of the fifth-calculated I||hash (R);

wherein IF the fifth-calculating proceeds correctly AND the information I is correct for the event AND the sixth-calculated hash (R) compares to the fifth-calculated hash (R) of the digital ticket as read THEN grant admission to a holder of the digital ticket ELSE IF the fifth-calculating proceeds incorrectly OR the information I is incorrect for the event OR the sixth-calculated hash (R) fails to compares to the fifth-calculated hash (R) of the digital ticket as read THEN deny admission to the holder of the digital ticket.

10. The method according to claim 9

wherein IF the fifth-calculating proceeds correctly AND the information I is correct for the event AND the sixth-calculated hash (R) compares to the fifth-calculated hash (R) of the digital ticket as read AND the read digital ticket is the first uniquely presented THEN grant admission to a holder of the digital ticket ELSE IF the fifth-calculating proceeds incorrectly OR the information I is incorrect for the event OR the sixth-calculated hash (R) fails to compares to the fifth-calculated hash (R) of the digital ticket as read OR the read digital ticket is not the first uniquely presented THEN deny admission to the holder of the digital ticket.

11. The method according to claim 9 that, between the extracting and the fifth calculating, further comprises:

second storing R in the event computer as an indication that the digital ticket has been tendered.

12. The method according to claim 8 where the ticket provider is also a ticket seller, the ticket consumer is also a ticket buyer, and the delivery of the ticket to the ticket consumer across the communications channel accompanies a sale of the ticket:

wherein the second transmitting further includes electronic payment suitable to the order data.

13. The method according to claim 8 wherein the first transmitting, the second transmitting and the third transmitting are upon a worldwide communications network.

14. The method according to claim 8 wherein the first transmitting, the second transmitting and the third transmitting are upon a worldwide secure or encrypted communications network.

15. The method according to claim 14 wherein the first transmitting, the second transmitting and the third transmitting are upon the Internet.

16. The method according to claim 15 wherein the first transmitting, the second transmitting and the third transmitting are upon the Secure Socket Layer (or SSL) of the Internet.

17. The method according to claim 8

wherein the first storing is in a transportable medium for delivering to the site of the particular selected event to there be tendered as a digital ticket by the ticket consumer.

18. The method according to claim 8

wherein the first storing is in the transportable medium of a printed substrate;

wherein the printed encrypted digital record is subsequently physically delivered to the site of the particular selected event to there be tendered as the digital ticket by the ticket consumer.

19. The method according to claim 18

wherein the first storing in the transportable medium of a printed substrate is in form of a two-dimensional bar code.

20. The method according to claim 19

wherein the first storing in the transportable medium of a printed two-dimensional bar code is in accordance with the PDF417 standard.

21. The method according to claim 19

wherein the first storing in the transportable medium of a printed two-dimensional bar code is in accordance with the QR standard.

22. The method according to claim 8

wherein the first storing in the transportable medium of a computer disk.

23. The method according to claim 8

wherein the first storing is in the transportable medium of a smart card;

wherein the digital record stored within the smart card is physically delivered to the site of the particular selected event to there be tendered as the digital ticket by the ticket consumer.

24. A system for delivering a digital ticket upon a communications network comprising:

a ticket consumer'"'"'s computer, connected to the communications network, the ticket consumer'"'"'s computer comprising means for first transmitting ticket order data upon the communications network to a ticket provider'"'"'s computer, means for first receiving upon the communications network from the ticket provider'"'"'s computer a digitally signed ticket data, and means for storing the digitally signed ticket data in a transportable storage medium;

a ticket provider'"'"'s computer, connected to the communications network, the ticket provider'"'"'s computer comprising means for second receiving from the ticket consumer'"'"'s computer upon the communications network the first-transmitted ticket order data, means for digitally signing the ticket data, and means for second transmitting the digitally signed ticket data upon the communications network to the ticket consumer'"'"'s computer; and

a communications network, the communications network comprising means for communicating at a first time the first-transmitting of the ticket consumer'"'"'s computer to the second-receiving of the ticket provider'"'"'s computer, and means for communicating at a second time the second-transmitting of the ticket provider'"'"'s computer to the first-receiving of the ticket consumer'"'"'s computer;

wherein the ticket consumer'"'"'s computer further comprises means for first calculating a number R, and means for second calculating a one way function of R to produce hash (R) as ticket data,

wherein the first transmitting is of the second-calculated hash (R) as the ticket data,

wherein the first receiving is of hash (R) and additional information I digitally signed with signature key s as Sign (s, I||hash (R)),

wherein the ticket consumer'"'"'s computer further comprises means for third calculating an appending of R to the digital ticket precursor Sign (s, I||hash (R)), giving Sign (s, I||hash (R))||R as a digital ticket and wherein the storing is of the third-calculated digital ticket Sign (s, I||hash (R))||R;

wherein the second receiving comprises receiving the first-transmitted hash (R) ticket order data,

wherein the ticket provider'"'"'s computer further comprises means for calculating a digital signature in respect of the ticket data and additional information I, in respect of signature key s as Sign (s, I||hash (R)), and

wherein the second transmitting comprises transmitting the calculated Sign (s, I||hash (R)).

25. The system for delivering a digital ticket according to claim 24

wherein the means for storing the digital ticket comprises means for printing the digital ticket.

26. The system for delivering a digital ticket according to claim 25

wherein the means for printing prints the digital ticket in a 2-D machine-readable pattern.

27. The system for delivering a digital ticket according to claim 26

wherein the 2-D machine-readable pattern comprises a 2-D machine-readable bar code pattern.

28. A system for delivering a digital ticket upon a communications network comprising:

a ticket consumer'"'"'s computer, connected to the communications network, the ticket consumer'"'"'s computer comprising means for first calculating a number R, means for second calculating a one way function of R to produce hash (R) as ticket data, means for first transmitting the second-calculated hash (R) ticket data upon the communications network to a ticket provider'"'"'s computer as a ticket data for a particular selected event, means for first receiving upon the communications network a digitally signed data in respect of signature key s of hash (R) and additional information I as Sign (s, I||hash (R)), means for third calculating an appending of R to the digital ticket precursor Sign (s, I||hash (R)) so as to give Sign (s, I||hash (R))||R in a digital ticket, and means for first storing the third-calculated digital ticket Sign (s, I||hash (R))||R in a transportable storage medium;

a ticket provider'"'"'s computer, connected to the communications network, the ticket provider'"'"'s computer comprising means for second receiving from the ticket consumer'"'"'s computer upon the communications network the first-transmitted hash (R) ticket data, means for fourth calculating digitally signed data in respect of signature key s of second-received hash R and of information I as Sign (s, I||hash (R)), and means for second transmitting the fourth-calculated Sign (s, I hash (R)) upon the communications network to the ticket consumer'"'"'s computer;

and a communications network, the communications network comprising means for communicating at a first time the first-transmitting of the ticket consumer'"'"'s computer to the second-receiving of the ticket provider'"'"'s computer, and means for communicating at a second time the fourth-transmitting of the ticket provider'"'"'s computer to the first-receiving of the ticket consumer'"'"'s computer.

29. A digital ticket procured by a ticket consumer upon a communication network from and by interaction with a ticket provider, the digital ticket comprising:

a tangible transportable data storage medium containing Sign (s, I||hash (R))||R where

(1) R is a number having its origin in a computer of the ticket consumer, which number R is appended to

(2) a number Sign (s, I||hash (R)) that was computed in a computer of the ticket provider as a digitally signature signed data in respect of a signature key s of a number hash (R) appended to information I, thus Sign (s, I||hash (R)), and subsequently communicated across the communications network to the computer of the ticket consumer, which number hash (R) was itself computed in the computer of the ticket consumer as a one way function of R, thus hash (R), and subsequently communicated to the computer of the ticket provider;

wherein number R, having its origin in a computer of the ticket consumer, is private to the ticket consumer and is not public, and

wherein the digital signature key s of the computer of the ticket provider is private to the ticket provider and is not public.

30. A digital ticket comprising:

a tangible transportable digital data storage medium containing

first-type data, originally known both to a buyer and to a seller of a ticket and meaningful to at least the seller of the ticket to identify, at least relatively, a particular event for which the ticket was sold, and

second-type data including a signed digital representation of a particular parameter that was originally computer-generated in a sequence first by the buyer of the ticket as a non-invertible function of a random number called a “

first-time-made non-invertible function”

, wherein the non-invertible function is a one-way hash function, and wherein the random number is uniquely known to the buyer and not to the seller, and then

second by the seller of the ticket as a digital signature of the first-time-made non-invertible function, and then

third by the buyer of the ticket to attach the selfsame random number;

wherein, to validate the digital ticket upon attempted redemption of the ticket,

the random number is detached, and then

the signed first-time-made non-invertible function is interpreted, recovering this first-time-made non-invertible function, and then

the non-invertible function of that selfsame random number just detached is newly made all over again, which newly made non-invertible function is called the “

second-time-made non-invertible function”

;

wherein the second-time-made non-invertible function EITHER equals the first-time-made non-invertible function IN WHICH CASE the ticket is not invalid OR ELSE the second-time-made non-invertible function does not equal the first-time-made non-invertible functional thus making the digital ticket is invalid for at least the particular event.

31. The digital ticket according to claim 30 wherein the digital signature within the tangible medium as read by a digital reader is further compared to a data base of digital tickets actually signed and sold not so as to determine whether a tendered digital ticket is valid or invalid but rather for statistical purposes.

32. The digital ticket according to claim 30 wherein the digital signature within the tangible medium is visible to the eye.

33. The digital ticket according to claim 30

wherein the digital signature visible to the eye is comparable by eye to a catalog of visual sensible representations of digital tickets actually signed and sold in order to determine whether a tendered digital ticket is valid or invalid.

34. A system for delivering a digital ticket from a ticket seller to a ticket buyer, the system comprising:

a communication channel comprising means for, at a first time, sending from a ticket seller to a ticket buyer data regarding events for which tickets may be had, means for, at a second time, sending from the ticket buyer to the ticket seller data representative of a non-invertible transformation of a number determined by the ticket buyer only, and means for, at a third time, sending from the ticket seller to the ticket buyer a digital signature of the non-invertible transformation, wherein the received digital signature of the non-invertible transformation is combined with the number to produce a digital ticket;

a ticket buyer'"'"'s computer, communicatively connected to the communications channel, the ticket buyer'"'"'s computer comprising means for determining the number, means for computing the non-invertible transformation, and means for combining the digital signature of the non-invertible transformation with the number to produce a digital ticket;

a ticket seller'"'"'s computer, communicatively connected to the communications channel, the ticket seller'"'"'s computer comprising means for computing, in respect of the non-invertible transformation received from the ticket buyer, the digital signature of the non-invertible transformation; and

a tangible portable medium of digital data storage connected to the buyer'"'"'s computer and storing the digital ticket;

wherein the communication channel is sending at the second time a random number.

35. The system according to claim 34 wherein the communication channel is sending at the second time a number representing the particular selected event.

36. The system according to claim 34 wherein the communication channel comprises:

a worldwide digital communications network.

37. The system according to claim 34 wherein the communication channel comprises:

a worldwide secure digital communications network.

38. The system according to claim 34 wherein the tangible portable medium of digital data storage comprises:

a computer disk.

39. The system according to claim 34 wherein the tangible portable medium of digital data storage comprises:

a printed medium.

40. A printed ticket bearing indicia CHARACTERIZED IN THAT the indicia includes a 2-D bar code containing a one-way function of a number provided by a holder of the ticket, the one-way function being digitally signed by a provider of the ticket;

FURTHER CHARACTERIZED IN THAT the 2-D bar coded indicia contains Sign (s, I||hash (R))||R where

(1) R is a number having its origin in a computer of a consumer of the ticket, which number R is appended to

(2) a number Sign (s I||hash (R)) that was

computed in a computer of a Provider of the ticket as a digital signature in respect of digital signature key s of the number hash (R) in combination with information I,

subsequently communicated across the communications network to the computer of the ticket consumer, which number hash (R) was itself

computed in the computer of the ticket provider as a one way function of R and subsequently communicated to the computer of the ticket provider;

wherein number R, having its origin in a computer of the ticket consumer, is private to the ticket consumer and is not public; and

wherein the digital signature key s of the computer of the ticket provider is private to the ticket provider and is not public.

41. A communications system for selling and delivering a digital ticket comprising:

a ticket buyer computer (i) sending at a first time a one-way transformation of a private number to a seller computer, (ii) receiving at a third time signed information from the ticket seller computer, and (iii) storing at a fourth time within a digital store the received encrypted signed information plus the private number;

a ticket seller computer (i) receiving at the first time the one-way transformation of the private number from the seller computer, (ii) signing at a second time this one-way transformation and additional information, and (iii) sending at the third time the signed first transformation and additional information to the ticket buyer computer as signed information; and

a digital store storing at the fourth time the signed information plus the private number as a digital ticket;

wherein upon (i) a reading of the signed information, (ii) a decrypting of the signed information to recover the one-way transformation of the private number, (iii) a reproducing with the same secure first transformation that the ticket seller used the secure first transformation of the number all over again, and (iv) a comparing of the decrypted recovered one-way transformation to the reproduced first transformation, validity of the digital ticket is assessable;

wherein the second communicating is of second digital data D₂ including a one-way function hash (R) of a number R which number R is uniquely known to the computer of the ticket buyer and not to the computer of the ticket seller.

42. A method for selling and delivering a digital ticket comprising:

first-sending at a first time a one-way transformation of a private number from a ticket buyer computer to a ticket seller computer, wherein the private number is a random number;

first-receiving at the first time the one-way transformation of the private number in the ticket seller computer;

signing at a second time the one-way transformation and additional information in the ticket seller computer;

second-sending at a third time the signed first transformation and additional information as signed information from the ticket seller computer to the ticket buyer computer;

second-receiving at the third time the signed information in the ticket buyer computer;

storing with the ticket buyer computer at a fourth time both (i) the received signed information plus (ii) the private number within a digital memory store;

storing within the digital memory store at the fourth time the signed information plus the private number as s digital ticket;

wherein upon (i) a reading of the signed information, (ii) a decrypting of the signed information to recover the one-way transformation of the private number, (iii) a reproducing, with the same secure first transformation that the ticket seller used, the secure first transformation of the number all over again, and (iii) a comparing of the decrypted recovered one-way transformation to the reproduced first transformation, validity of the digital ticket is assessable.

43. In a communications system having a computer of a ticket buyer bi-directionally communicating across an insecure digital communications network to the secure computer of a ticket seller, a method for selling and for delivering a digital ticket from a ticket seller to a ticket buyer, the method comprising:

at a first time first-sending from the computer of the ticket seller across the communications network to the computer of the ticket buyer first data regarding events for which tickets may be had;

then at a second time

second-sending from the computer of the ticket buyer across the communications network to the computer of the ticket seller second data identifying and event for which a ticket is desired, the second data accompanied by a secure first transformation of a number that is determined by the ticket buyer only and unknown to others including the ticket seller;

then at a third time

third-sending from the computer of the ticket seller across the communications network to the computer of the ticket buyer third data confirming ticketing to the event for which the ticket was desired, the third data accompanied by a secure second transformation of the secure first transformation; and

then

storing, with the computer of the ticket buyer within a tangible portable medium of digital data storage, (i) the number in accompaniment to (ii) the secure second transformation;

wherein upon (i) transportation of the digital data storage medium to a physical site of the event, (ii) reading of the number to a computer, and, by use of the same secure first transformation that the buyer did use, reproduction of the secure first transformation of the number all over again, plus (iii) reversing of the secure second transformation by an event computer privileged to knowledge of said second transformation, then a (ii) read and reproduced first transformation is comparable to a (iii) first transformation recovered from reversing the second transformation in order to assess validity of the digital ticket;

wherein the communication channel is sending at the second time a random number.

44. The method according to claim 43 wherein the second-sending is of the second data accompanied by a secure first transformation in the form of a one-way hash function of the number.

45. The method according to claim 43 wherein the third-sending is of the second data accompanied by a secure transformation in the form of a digital signature of the secure first transformation.

46. The method according to claim 43 wherein the storing within a tangible portable medium of digital data storage comprises:

printing.

47. The method according to claim 43 wherein the printing is of at least the (ii) secure second transformation in the form of a two-dimensional bar code.