CA2706673A1 - Device and system for practical entropy collection from dice - Google Patents

Abstract

For gaming, gambling, and lottery systems, and for cryptographic processors in server systems, pseudo-random number generators (PRNG) need to be seeded with truly random data, and it is usually considered important that this random data is made of fair bits with good statistical properties. The invention uses a special set of dice to be handled according to rules for 1) dice shuffling, 2) putting dice to rest in a conventional position, and 3) sensing the discrete outcome. The required system logic is disclosed so that the overall process of random outcome generation, sensing, and conversion into internal random data can be supported by the digital systems that need it. The bar code technology is applied in a novel arrangement such that the whole process is efficient and secure.

Description

TITLE OF THE INVENTION

Device and System for Practical Entropy Collection from Dice FIELD OF THE INVENTION

[0001] The invention relates to entropy collection, or secret truly random data generation, for digital electronic systems preforming logic functions with random characteristics, such as gaming or gambling machines, information security systems using locally generated secret random data for cryptographic key material, and the like. The invention materializes as a variation of the classical six-faced cubic die, and enhancements in digital systems, both suited to this purpose of entropy collection. The invention is only remotely related to the direct use of dice for games or gambling.

BACKGROUND OF THE INVENTION

[0002] It is hard to provide trustworthy and reliable means of generating secret random binary data with good statistical distribution for use in a computer system.
Generally, a reliable system has a predictable behavior, and the very notion of randomness is suggesting some erratic behavior. Indeed, deterministic pseudo-random sequences are often preferred for computer simulations because a simulation run may be reproduced in the event of a software bug with a given sequence of pseudo-randomly generated events or observations.
Other types of systems nonetheless require the closest possible equivalent to secret truly random binary data. Two broad categories of systems are relevant to the present invention:
gaming, gambling, or lottery machines, and digital systems dedicated to IT
security functions with a high security level. The inventor refers to systems for which the operational rules might specify a complete system halt in the case of secret random source malfunction (instead of a degraded operational mode that might turn a fair gaming machine into an unfair one). While mundane IT security applications in general purpose computer systems are typically not operated this way, the present inventor brings the present disclosure within a larger effort to use common computer components and the general purpose Linux operating system for cryptographic functions traditionally implemented in dedicated hardware security modules.

[0003] The typical strategy for providing a secret random source is a combination of digital sampling of an unpredictable phenomenon, some processing of raw sample data usually intended to output binary digits with a 50% probability of either value, and some pseudo-random number generation algorithms. Diversified unpredictable phenomenon has been used, from fundamental properties of atomic particles to the precise timing of user keystrokes on a computer keyboard. Electromagnetic or acoustic noise is sometimes used.
As an operating system kernel switches the CPU resources among competing processes, some observations of non-deterministic event sequences becomes available as a contribution to the random source function. To some extent, the unpredictability of the very sampling operation (e.g. an instrument sensor precision limit) may contribute to the variability in the raw samples. In most cases, the random data acquisition rate is orders of magnitude slower than the typical data processing or transmission pace of modern computers.

[0004] In these prior art arrangements, the system is autonomous in truly random data acquisition (no operator intervention). This makes it convenient for system application designers to rely on the random data acquisition on a regular basis during system operations.
It is however very difficult to detect malfunctions in the secret random source, either with a generic statistical test (notably the acquisition rate is too slow) or with a specific self-test in the unpredictable phenomenon sampling process. Sometimes, a gaming system fraud agent or an IT security hacker might attempt to freeze or inhibit the unpredictable phenomenon such that the system operations quietly turn more deterministic to the fraud agent or hacker advantage.

[0005] The prior art makes it difficult for a given unpredictable phenomenon sampling arrangements to remain applicable and available within reasonable costs through the technological evolution of electronics and digital systems. The system bus architecture might become obsolete so that a sampling peripheral is no longer supported.
Electronic components that are not used in their exact intended function may be modified by the component manufacturer in unexpected ways. Some assumptions in a system operating environment may no longer apply to new digital system paradigms (e.g. solid state mass storage or processor virtualization).

[0006] For critical systems, a need for third party certification and/or audit arises (i.e.
independent from the vendor and operating entity). In this context, certification applies to the system design and manufacturing, and auditing applies to the system operations. In both cases, the prior art reliance on diversified unpredictable phenomenon sampling may make the certification or audit quite challenging. Without a universally accepted truly random data acquisition arrangement, the statistical validity of a custom approach has to be demonstrated with a heightened level of scrutiny, often requiring extensive scientific knowledge. With the system vendor employees having an intimate understanding of the exclusive implementation details, the certification personnel should even watch for a hidden trap-door in the system.

[0007] There is thus a need for enhanced arrangements to provide a secret random source to digital systems for to circumvent the prior art deficiencies associated with the autonomous sampling of selected unpredictable phenomenon.

BRIEF DESCRIPTION OF THE INVENTION

[0008] The invention revisits the prior art idea of a permanent autonomous secret truly random source in the gaming, gambling, or IT security system. A properly seeded pseudo-random number generator (PRNG) can provide the required secret random source, provided a) it is indeed initially seeded from a secret truly random source, b) the PRNG state is kept secret through the system operational life cycle, and c) the PRNG is cryptographically strong and has a large period. A security specialist comfortable with the prior art may be rebutted by the criticalness of PRNG state protection, but it comes with the benefit of hardware system design simplification.

[0009] The PRNG seeding occurs through deterministic data collection representative of the random outcome drawn from a set of dice having been shuffled. The outcome data collection is deterministic in the sense that errors in the data collection are avoided as much as possible because no statistical properties might be relied upon from data collection error patterns. In essence, operations of both a game and the present invention comprise four phases: 1) dice shuffling, 2) putting dice to rest in a conventional position, 3) sensing the outcome, and 4) acting on the outcome. The present invention pertains to the set of dice and the system used in these operations. Both the inventive set of dice and the inventive system enhancements have characteristics matching the dice handling (phases 1 and 2) and the outcome collection (phase 3) rules.

[0010] The invention may be useful for seeding PRNG in systems where PRNG
state secrecy is not important, e.g. in stochastic computer simulations. The invention may also be useful in applications where truly random data can be used without the randomness expansion of a PRNG, such as the direct generation of a long-term private key for discrete logarithm public key cryptosystems (those types of long-term keys are not subject to number-theoretic restrictions).

[0011] Thus, the present invention uses the basic operation of rolling a cubic die as an unpredictable phenomenon. Flipping a coin or rolling a die other than a cubic one would equally fit. This means that the system is not autonomous in truly random data collection, i.e.
a human operator intervention is needed. Thus, when a system is initially put into production, its PRNG state is virgin and must be initialized. A single occurrence operator session happens at this point, during which the operator handles the inventive dice with the procedure to be described below, and the secret data drawn from the dice handling is fed into the system according to the detailed arrangements described below. The secret PRNG
state is thereafter initialized and preserved through system shutdowns and reboots (e.g. like in the Linux kernel) with the required secrecy protections. As should be obvious to an expert in cryptographic systems, some exceptional circumstances may trigger a requirement for a rehearsal of the operator session, i.e. if the PRNG state secrecy is jeopardized following some security incidents.

[0012] The invention provides many benefits from the fact that the faces of the inventive dice are labeled with bar codes instead of the numbers 1 to 6.
Operator efficiency is one such benefit. But an unusual benefit arising from the bar code technology in the present invention preferred mode is data secrecy: the bar code visible on each die face is devoid of a human readable counterpart of the bar code contents (i.e. no numbers or letters appear below the bar code). This is against the recommended practice for bar code application design as it prevents manual keyboard entry when a bar code is dirty or damaged and can not be input with a bar code scanner. It also means that special care has to be taken for bar code scanning errors. The procedure for inventive dice handling is adapted accordingly.

[0013] The preferred mode is a set of 36 different dice, giving 216 (216=36*6) faces each having a different encoded bar code indication. The system software logic is based on the knowledge of these 216 bar code indications applicable to die 1 face 1, die 1 face 2, and so on up to die 36 face 6. This allows to cope with errors caused by duplicate or unintended scan.

[0014] Duplicate scans occur when the same bar code label is scanned twice in succession. Bar code scanner devices come with firmware-based duplicate rejection logic, but if a single die was used in the invention, this would interfere with the intentional capture of two identical random draw outcomes. E.g. with the inventive set of dice, two 5 in a row might be scanned as die 17 face 5 followed by die 3 face 5, which are not duplicates for the scanner firmware logic.

[0015] Unintended scans (for the present invention bar code application) are those for a die face other than the drawn outcome: if the scanner is positioned such that two or three faces are in the scanner field of view, any of these might be scanned depending on the scanner capabilities. It is usually seen beneficial to data entry efficiency when a scanner decodes a bar code positioned at various angles or orientation (and distance as well). When a die stands free on a flat surface, any of the 4 faced adjacent to the one at the top might cause an unintended scan. With the 216 distinct face indications, it is possible to detect an unintended scan. E.g. a scan of die 27 face 2 followed by die 27 face 4 suggests an unintended scan. Other invention characteristics allow better handling of seemingly unintended scans in the digital system software logic.

[0016] The preferred mode of the invention uses a simple bidirectional scanner, using the CCD linear array technology instead of a more powerful omni-directional models. For instance the Opticon OPT-6125 model has been found useful (the Opticon model number has been changed to LGP-6125 for this device). This limited scan orientation matches the bar code label orientation on the inventive dice: for any two adjacent faces of any die, the two respective labels appear perpendicular when looking at the two faces at a 45 degrees angle of view. The dice handling and outcome collection rules make use of the linear scanning property and the orthogonal polarization of bar code labels in adjacent die faces. If a scanner device could report by a flag whether the scanned label was read left-to-right or right-to-left (such a capability would require a small custom bar code reader firmware modification), the present invention could make good use of this additional data. The preferred mode uses off-the-shelf bar code reader equipment for ease of procurement.

[0017] If a die stands free on a flat surface, 4 faces may trigger an unintended scan. If one of these faces is aligned to a vertical surface (e.g. the side of a box), it disappears from a scanner device field of view. Moreover, if two other dice are positioned on each side of the first one and also rest aligned to the vertical surface, two other faces of the first die disappear from the scanner device field of view. This leaves 2 faces available to the scanner, and they are orthogonal.

[0018] With the recommended dice handling procedure, the dice are shuffled and then set to rest in a single line along a small vertical wall, next to each other.
With 19 millimeters dice, what was found convenient is a 30 inches long board with an L shaped section and having 6 and 1 inches wide perpendicular surfaces. With such a single contiguous alignment of dice in the angle of an L-shaped board, each die offers two faces to the scanner field of view, except for two dice at each end of the alignment which offer an extra face at each end.

[0019] From the above conventions about how the inventive set of dice should rest before the outcome collection phase is undertaken, outcome collection rules may be specified that allow the digital system software logic to avoid unintended scans or other errors and collect all relevant discrete information available in the random outcome. The details are disclosed further below. Thus, the inventive digital system enhancements allow the collection of truly random data with good statistical properties with a random process (dice shuffling) which is easily certifiable or auditable, and immune to technology obsolescence associated with custom electronics. This is achieved while protecting the secrecy of the truly random data as is needed for PRNG seeding in IT security and gaming, gambling, and lottery applications.

[0020] A few observations may be made about human factors in the unusual data entry assignment implied by the present invention.

[0021] The secrecy of truly random data rests in a normal person's inability to visually decode bar code labels and memorize the discrete outcome so observed. It could be that very unusual personalities with exceptional attention to details are able to decode and memorize the discrete outcomes. If such an individual is allowed at all to work with security critical systems, some attention should be paid to their ability to cheat. Still, the invention may be implemented such that this person's mental challenge is greater by a fixed permutation of dice face labels, so that the visual decoding of labels would not easily translate into dice and face numbers.

[0022] The true randomness depends on sufficient shuffling applied to the set of dice, but this cannot be readily verified by the system software. Thus, the shuffling operation effectiveness may be ascertained only through some form of operator supervision, auditing, or dual control (as is known in the field of manual cryptographic key management).

[0023] It may be noted that the data entry assignment is a dice handling procedure, which could be entertaining if it was part of a game. Since the exact outcome has no consequence for the operator, the procedure performance becomes simply boring, devoid of any meaningful feedback or intrinsic rewards. This suggests to bring back some operator feedback which would otherwise be useless. Notably, the detailed software logic may allow some trivial data entry error detection and correction, from which an operator compliance mark could be established and displayed as operator feedback.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The Figure 1 is a simple perspective view of a die in the inventive set of dice.

[0025] The Figure 2 is a flat representation of the 6 faces of an inventive die where the bar code labels has been replaced by legible indications of each face number and the respective bar code label orientation.

[0026] The Figure 3 shows the inventive set of dice aligned according to the dice handling rules that facilitate random shuffling outcome collection by the inventive digital system enhancements.

[0027] The Figure 4 shows a complete example of a dice shuffling outcome where the bar code labels on each die has been replaced by legible indications of die face numbers for two adjacent faces, the two respective bar code label orientations, and the die number.

[0028] The Figure 5 shows the logical arrangement of an engraving process proof for the convenient manufacture of the inventive dice set.

[0029] The Figures 6a) and 6b), when mated along the V indentations at the bottom of 6a) and the top of 6b), show an actual engraving process proof logically depicted in figure 5.
DETAILED DESCRIPTION OF THE INVENTION

[0030] Each die in the inventive set looks like the figure 1. Even if the dice are uniquely labeled within the set, they are difficult to distinguish without close examination by someone trained in the specific bar code symbology. This provides some assurance of unbiased handling and secrecy of dice shuffling outcome.

[0031] The Codabar bar code symbology is used in the preferred mode because it allows short bar code labels made of a single start element (selected among the 4 defined in the Codabar symbology), a single data symbol (selected among 16 defined in the Codabar symbology), no checksum element, and a single stop element (selected among the 4 defined in the codabar symbology). No restriction apply to these short bar code labels, so that 256 different labels would allow up to 42 dice in the set (6 different labels are required for the 6 faces of each die). Sixteen millimeter dice has been found large enough for these bar code labels, but larger dice may be used to ensure improved scanner device performance with slightly larger bars (i.e. larger than the 7.5 mils narrow bar thickness that was used).

[0032] Conventional cubic dice are labeled such that the outcome of opposite faces add up to 7. In the preferred mode dice, any two adjacent faces on a die have their bar code labels perpendicular to each other. The preferred mode outcome sensing procedure relies on this convention. Two further die labeling conventions are specified in here merely because they make the design details unambiguous (they are also useful for what seems the best mode of manufacturing the inventive set of dice). Firstly, one of the angles of view showing three die faces must show the faces 1, 2, and 3 appearing in a clockwise direction around the tip closest to the observer (as a consequence of these conventions, the angle of view showing the three faces 4, 5, and 6 shows them also in a clockwise direction).
Secondly, the direction of reading a face indication from left to right must point from face 1 to face 2, from face 2 to face 3, from face 3 to face 1, from face 6 to face 5, from face 5 to face 4, and from face 4 to face 6.

[0033] The resulting die layout is depicted in Figure 2 in which the 6 faces are flattened as if the die was made from a foldable cardboard material. Also, the bar code labels of an actual die has been replaced by legible indications of each face number and the respective bar code label orientation.

[0034] The inventive set of dice is intended to be shuffled and the set to rest so that the random draw discrete outcome may be input to the digital system and converted to useful secret random data with the inventive programmatic means. The dice handling procedure includes a random alignment of the dice such that two adjacent faces of each die are available to a bar code scanner. This is shown in figure 3 where an L shaped board (100) offers a surface for setting the dice to rest and aligning them in a single alignment (101). The two ends of the alignment (102, 103) may be ignored in the outcome collection rule, or a scan of their bar code labels might be specified as an additional data validation step. The discrete outcome to be collected is fully contained in the row of bar code labels visible on top of the alignment (101) plus the row of orthogonal bar code labels visible in front of the alignment (101).

[0035] The figure 4 is an example of a complete discrete outcome to be collected, with the actual bar code labels replaced by legible indications of each face number and the respective bar code label orientation. There are thus two rows of orthogonal bar codes. Also shown in figure 4 is the die number for each of the 36 positions in the alignment rows.

[0036] The characterization of the discrete outcome information available to the outcome sensing phase is a simple counting problem in combinational mathematics. With every die in a linear sequence having its own number, a permutation of 36 objects is present.
Moreover, each die is aligned, having exactly one ridge positioned at the intersection of its two visible faces (there are 12 ridges at the intersection of the 6 die faces). Finally, there are two possible orientations for the aligned or winning ridge, e.g. if the ridge between faces 1 and 5 is the winning one, the outcome may be further characterized from which of 1-5 (figure 4, 202) or 5-1 (figure 4, 202) is visible from the top-front observation positions pair. Overall, each independent die position is selected among 24 possibilities of equal probability. Another way to come to this count of 24 positions is that if a given face (among 6) is visible from the top observation position, there are exactly 4 independent choices for the front observation position. Overall, the available entropy is 303.15 bits (i.e. the base 2 logarithm of 36 factorial times 24 raised to the power 36) instead of 93.06 bits for the simple outcome sensing approach (i.e. the base 2 logarithm of 6 raised to the power 36).

[0037] With these conventions, the preferred outcome sensing procedure using a bidirectional hand held bar code scanner may be described. In this context, the scanner movement may be perpendicular to the dice alignment or parallel to it. Since the two adjacent faces visible for any die in the alignment have perpendicular bar code orientations, one of them will be scanned with a perpendicular scanner movement and the other one will be scanned with a parallel scanner movement.

[0038] The first step in the preferred outcome sensing procedure is a perpendicular scanner movement varied laterally (or rolled) (between the top and front observation positions) to capture one bar code label (the one easily scanned with a perpendicular movement) from each die in the alignment, in sequence. This provides the system with the ordering of dice (the permutation outcome) in the alignment, plus a first indication of the independent outcome for each die. With the example data in figure 4 and a left to right scanner movement along the dice alignment, the following sequence will be scanned (each die is indicated with a bracketed pair of integers, respectively the die and face number).

[0039] This first sequence is [30,2] [21,3] [25,3] [26,2] [16,3] [20,5] [17,4]
[19,6] [24,5]
[8,1] [12,1] [5,2] [23,6] [35,6] [4,3] [2,3] [31,3] [18,4] [36,6] [34,6]
[27,2] [10,2] [28,4] [14,9]
[29,2] [33,3] [6,3] [11,1] [22,4] [3,4] [13,6] [32,1] [9,2] [1,3] [7,3]
[15,1].

[0040] The second step is another perpendicular movement in the same direction along the dice alignment, but this time limited to a single observation position for the scanner field of view, e.g. the top one. At this step, statistically one half of the dice in the alignment will be captured. Again with the example data in figure 4, the following sequence will be scanned.

[0041] This second sequence is [30,2] [12,1] [4,3] [31,3] [34,6] [28,4] [29,2]
[33,3] [3,4]
[13,6] [32,1] [15,1].

[0042] The third step is a parallel scanner movement still in the same direction along the dice alignment, and limited to the same single observation position for the scanner field of view (e.g. the top one). Normally, those dice that were not captured in the previous step will be captured now, giving a complete indication of dice positions for those.
Again with the example data in figure 4, the following sequence will be scanned.

[0043] This third sequence is [21,6] [25,1] [26,3] [16,6] [20,4] [17,1] [19,2]
[24,4] [8,5]
[5,3] [23,5] [35,5] [2,6] [18,6] [36,5] [27,3] [10,3] [14,2] [6,1] [11,2]
[22,6] [9,3] [1,6] [7,6].

[0044] The fourth and last step is a second parallel scanner movement still in the same direction along the dice alignment, with the other other observation position for the scanner field of view. This completes the dice position information for the dice missing from the third step (e.g the front one shown as the bottom row in the figure 4). Again with the example data in figure 4, the following sequence will be scanned.

[0045] This fourth sequence is [30,4] [12,5] [4,1] [31,6] [34,2] [28,1] [29,4]
[33,1] [3,6]
[13,5] [32,2] [15,2].

[0046] For the parallel scanner movements, because the bar code labels are are short and close to each other, it is useful to blind the scanner for a portion of its field of view. e.g.
with a finger of the hand that holds the scanner device.

[0047] The above outcome sensing procedure implies data validation rules for the system software that converts scanned bar code data input through a system port into validated truly random data. The sequences indicated above are those expected in the absence of errors induced by the scanning process or inadequate operator compliance. Some errors may be ignored, like duplicate scans in succession. Other errors may be fixed, such as a missing scan from the second sequence for a die number that is present in both the first and fourth ones, with coherent values (in fact, the second sequence would not be useful if the scanning process and operator compliance were perfect). Other errors may induce the system software to obliterate data elements from the discrete outcome. If a die number is absent from both the third and fourth sequences, an independent die result (out of 6 possibilities) may still be used from the first sequence value (instead of an independent die result out of 24 possibilities). If a die number is totally absent or reported incoherently, it may be obliterated both as an independent result and as an element in the random permutation.

[0048] The inventive digital system enhancements are functions typically implemented in software, or programmatic means. The software has to process the input stream of bar code values and reconstruct a validated internal data representation of what appears in figure 4. For instance, the start of the second sequence may be detected if all (or nearly all) die numbers has been scanned (i.e. a complete first sequence) and a die number detected early in the first sequence is detected again. Bar code scanned commands (e.g. an "end of sequence" indication) could be interspersed in the input stream for an easier software function implementation, but too much reliance on such command scans may reduce operator efficiency. At a minimum, a "restart sequence" command would be useful because the operator is deemed at some point to become conscious of an unrecoverable error. The "restart command" may be a short sequence of dice face scans that is impossible in the normal outcome collection procedure and very unlikely as an unintentional error (e.g. coming back to the same dice face label three times within 5 to 8 consecutive scans may indicate the operator willingness to abandon the current outcome collection sequence and start anew).

[0049] Once a validated internal representation exists for the discrete outcome as scanned, the next logical step is to convert it into an index in an implicit enumeration of the theoretical set of possible outcomes. Stated differently, a discrete outcome turns into an integer from 0 to N-1, where N=2"142*3"53*5"8*7"5*11"3*13"2*17"2*19*23*29*31 is the exact factorization of 36 factorial times 24 raised to the power 36. From this random index expressed in a binary representation, only the least significant 142 bits are guaranteed to be perfectly fair. This introduce a difficulty in the system software if a theoretical reasoning is required to certify that every truly random bit is fair.

[0050] Here is an explanation of a reasonable solution, using smaller numbers.
If we take the discrete outcome of a French roulette as a source of true randomness, we get an index between 0 and N-1=36 for N=37. The base 2 logarithm of 37 is about 5.21, so this is the theoretical maximum average number of fair bits we can collect from repeated roulette draws.
The simplest fairness assurance heuristic is to collect 5 bits if the outcome is between 0 and 31 inclusive, and none otherwise. This gives an average of 4.32 bits per draw.
A first refinement is possible from the fair distribution of outcomes in the range 32 to 36 inclusive when the draw is rejected: if the draw is between 32 and 35 inclusive, we may collect two bits from the drawn number minus 32 in the range from 0 to 3. We gained 0.22 bits on average, with an overall efficiency of about 87%. We must collect no bit for an outcome of 36. A second refinement is that the random roulette outcomes may be lumped in groups of 5 (with an efficiency over 99%, it is the most efficient choice with the limitation of 32 bits arithmetic), so that the grouped outcome is between 0 and N-1 with N=37A5=69343975=2A26+2A21+2A17+2"12+2"11+2"9+2"7+2"6+2A4+2"2+1 (the latter reflects the binary expansion of N). From the exponents 26, 21, 17, 12, ... in the binary expansion of N and the random index value, we get the following heuristic: if the index is below 2"26, take the least significant 26 bits as fair random bits, else if the index is below 2"26+2"21, take the least significant 21 bits, else if the index is below 2"26+2"21+2"17, take take the 17 least significant bits, and so on. These indications should allow a skilled software designer, engineer, or programmer, to avoid the pitfall of validating a truly random outcome and then converting it into a binary stream without assurance of good statistical properties.

[0051] Turning back to the discrete outcome counting that would be expected from the present invention with dice and face identification in the raw data, the outcome index value can be expressed as a mixed radix number (reminder: 93784 seconds is zero weeks 1 day 2 hours 3 minutes and 4 seconds in the everyday radix number base 7,24,60,60 that we use to count time) with number base elements selected from the factorization indicated above. This formulation may remain in the abstract: it merely states that every possible outcome element is taken into account in a number representation which is statistically fair (every possible digit in each position of the index representation has the same probability). In the actual software, the random permutation may be handled as a series of actual outcomes indices out of respectively 36, 35, 34, 33, up to 2 possibilities, and the independent dice adjacent face indications may be handled as outcome indices out of 24 possibilities. The preceding heuristic for the binary fairness in the software conversion would be applied either to the digits in the combined index represented as a mixed radix number, or to these elementary outcome indices in the actual software suggestion.

[0052] The required software may be developed by a skilled software designer, engineer, or programmer without further inventive activities. Such software would be much influenced by the typical constraints imposed by the operating system, computer language in use, bar code input interface details, system or application interface for the output secret binary random data, source code conventions, and the like. Once tested and verified to perform the intended conversion from bar code scan data to truly random secret binary data for system or application use, the software may be included in a system release to provide the enhanced inventive system.

[0053] The inventive set of dice may conveniently be manufactured in lots of 6 sets.
With the preferred count of 36 dice per set, a slab of 216 blank dice arranged in an 18 by 12 rectangle and deposited on a tray may be engraved at once by laser etching or other process.
As shown in figure 5, the faces 1 to 6 for each die in the set may be engraved with a single run of the engraving process. The figure 5 shows the slab divided in 6 sections for the 6 faces. Each die is represented in the figure 5 with the face and die number (respectively with the large and small font numbers), and the bar code label orientation. The logical arrangement turns into a bar code label arrangement shown in the figures 6a) and 6b) which, when mated along the V indentations at the bottom of 6a) and the top of 6b), show an actual engraving process proof for the disclosed manufacturing operations.

[0054] Once a slab of 216 blank dice has been engraved on one face, an employee rotates the dice sets, from 1 to 2, from 2 to 3, from 3 to 6, from 6 to 5, from 5 to 4, and from 4 to 1. In doing so, the employee maintains the die number correspondence one-to-one and pivots the die 90 degrees such that each die is deposited to receive another engraved bar code label for another face. The orientations in figure 5 are such that a die movement by 1 position (i.e. from 1 to 2, from 2 to 3, from 6 to 5, and from 5 to 4) implies a pivot indicated by the arrow (the adjacent blank face pointed to by the arrow is brought on top), and conversely a die movement by 3 positions (from 3 to 6 and from 4 to 1) implies a pivot against the direction of the arrow (the adjacent blank face in the opposite direction of the arrow is brought on top). This can be tried with six mock-up dice made from cut and taped copies of figure 2.

[0055] After five dice rotation operations each followed by an engraving of the bar code labels corresponding to figure 5, the 216 dice will be completely engraved on their 6 faces, and the 6 sets will be complete.

[0056] Although the invention has been disclosed in the preferred mode, it should be obvious that many variations are possible while remaining within the bounds of the inventive concept, which is set by the claims. The outcome rules, which includes the rules for 1) dice shuffling, 2) putting dice to rest in a conventional position, and 3) sensing the discrete outcome, may be as simple as the centuries old usage rule for cubic dice: roll them so that they rest on an horizontal surface, and observe which face of each die appears on top. The number of dice in the set may be varied from the preferred mode of 36.
Different bar code symbologies or conventions may be used, e.g. to allow a much larger set of die face indications. Dice other than cubic ones may be used. Thoroughly obfuscated bar codes may be used with the black-on-black technique where two different black inks are used for the background and the bars, respectively a vegetable die black ink for the background and an ink based on carbon pigments for the bars, and an infrared bar code scanner is used (the former ink type is often transparent to infrared wavelengths).

Claims (10)

1. A set of dice having bar code labels as die face markings where each said bar code label uniquely identify the die face in the whole set.

2. A set of dice as in claim 1 where the bar code labels are devoid of legible indications of the bar code data.

3. A set of dice as in claim 1 where each pair of adjacent faces on each die has perpendicular bar code label orientations.

4. In a digital system making system or application use of truly random data, the improvement characterized by programmatic means for converting external bar code capture data in an external format representative of a plurality of discrete indications of die faces into an internal data representation suitable for system or application use as truly random data, where said discrete indications of die faces are within a limited set of indications, any of which is representative of at most one face on one die, and said bar code capture data is subject to dice outcome rules; where said programmatic means embed data validation logic implied by said limited set and some processing logic implied by said dice outcome rules.

5. A digital system as in claim 4 having a pseudo-random number generator (PRNG) among its system or application components, where said system or application use includes the seeding of said PRNG state using at least a portion of said internal data representation.

6. A digital system as in claim 4 where said outcome rules include the bar code scanning of two adjacent faces of a cubic die.

7. A digital system as in claim 6 where said outcome rules provide deterministic clues about which of the two adjacent faces lies physically in a conventional position.

8. A digital system as in claim 4 where said outcome rules include the compulsory use of a bi-directional scanner device and bar code scanner orientation provisions.

9. A digital system as in claim 8 where said outcome rules further mandate that said bi-directional scanner device be able to report whether a bar code label has been scanned in the forward or reverse direction.

10. A digital system as in claim 4 where said outcome rules include the bar code scanning of die faces in a physical order in which the dice rest at the time of scanning.