AU2007324341A1 - Device for keeping track of passwords - Google Patents

Description

WO 2008/061302 PCT/AU2007/001787 "Device for keeping track of passwords" Cross-Reference to Related Applications The present application claims priority from Australian Provisional Patent Application No 2006906493, Australian Provisional Patent Application No 5 2007902733 filed on 21 November 2006, 22 May 2007, the contents of which are incorporated herein by reference. Field of the Invention This invention relates to a device for keeping track of passwords. 10 Background of the Invention There is an ever increasing use of automatic teller machines, computers, and the Internet, for carrying out transactions, particularly for financial transactions. In order to access a secure internet site, carry out financial transactions on the internet, log onto a website where purchases may be made, a person must typically be registered with that 15 site or for that particular activity and to have a user name and a password. In order to withdraw money from an automatic teller machine a person requires a bankcard or credit card and a PIN number. A person who has a number of bank accounts and credit cards, uses the internet for banking and other transactions, and uses a computer at work, may require anything 20 from ten to twenty, or more, different PIN numbers and/or passwords to operate their various bank accounts, access their computer and conduct transactions at various websites. Of course, it is possible for that person to have just one or two easily remembered passwords or PIN numbers, and use the same password or PIN number for carrying out a number of different transactions. However, to do so, represents a 25 security risk since if that person's password or PIN number is compromised or disclosed in any way, that may provide access to the majority of that person's bank accounts, registrations and the like, rather than just one. Consequently, it is generally recommended that a person has a different password or PIN number for each bank account, website registration, and the like. 30 Computer software has been written to assist in cracking a password and such software is available for purchase and on the Internet. Early examples of password cracking software were particularly adept at cracking passwords which comprised letters only or numbers only. More recent versions can crack passwords which comprise mixtures of letters and numbers. For security reasons, it is now generally 35 recommended that passwords contain more characters, with a mixture of numbers and WO 2008/061302 PCT/AU2007/001787 2 upper and lower case letters, and even other keyboard keys such as @, #, or %, and do not contain recognisable words, to make it more difficult to crack such passwords. Consequently, whereas in the early days of the use of password access for electronic transactions and the like, a person might have an easily remembered 5 password such as their daughter's or wife's name, nowadays passwords have to be more complex to be secure, and are less easily remembered. Moreover, a person will typically have more passwords to remember than they might have had a few years ago as more and more activities and transactions require a password/PIN number. Most people are incapable of remembering many different complex passwords, particularly 10 infrequently used passwords, and have to write those passwords down in some form so that they can be looked up if necessary. Of course, writing a password down is a security risk, thus, the password has to be disguised in some fashion. Many people are often somewhat unoriginal in the manner in which they disguise passwords and PIN numbers and this again, leads to 15 security problems. The present invention seeks to provide a device for keeping track of passwords which addresses and aims to at least partly alleviate some of the problems of the prior art as discussed above. Any discussion of documents, acts, materials, devices, articles or the like which 20 has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application. 25 Summary of the Invention In a first aspect, the present invention provides a device for keeping track of passwords comprising; a first surface marked with a pseudo random binary sequence (PRBS) arranged 30 in a loop and a series of characters aligned with bits of the pseudo random binary number; and a second surface also marked with characters arranged in a loop/ring; wherein at least one of the first or second surface is at least partly transparent or defines transparent areas or windows such that it may be superposed on the second or first 35 surface respectively with characters of that second or first surface visible through the windows/transparent areas of the other surface; and WO 2008/061302 PCT/AU2007/001787 3 a means for indicating the relative alignment of the superposed surfaces. In use the surfaces may be superposed in a particular orientation indicated by the means for indicating the relative alignment of the superposed surfaces. This gives a particular combination of characters in a ring/loop comprising characters from both 5 surfaces depending on the relative orientation. In the superposed arrangement, the PRBS, which may be disposed on or visible through the top surface, is adjacent a ring of characters each of which is generally aligned with a bit of the PRBS. Next a location on the PRBS is determined (by a number from 0 to 31, if the PRBS is a 32 bit PRBS). A protocol determined by the user determines how the characters adjacent the 10 location define a password. Typically, the PRBS is a 16 or 32 digit PRBS. The surface may be planar and defined by a sheet of material such as cardboard, plastic laminate, or any other suitable material. In an alternative embodiment, instead of being transparent, the second sheet 15 may define windows or apertures through which parts of the first sheet may be viewed. A protocol for using the cards could specify first the character that gives the correct orientation, next the correct PRBS to read (inner or outer circle), a decimal number from 0 to 31 indicating the read frame position on the PRBS to commence reading from and the number of characters to read. 20 The surface may be planar and defined by a sheet of material such as cardboard plastic laminate or any suitable material. In a less preferred embodiment, instead of the indications representing binary ones or binary zeros being arranged as a true pseudo-random binary sequence, they are arranged substantially as a pseudo-random binary sequence of bits i.e. a sequence 25 which is close to being a pseudo-random binary sequence, but with one or two bits in the sequence substituted. Reference herein to a PRBS should be taken to include such substituted pseudo random binary sequences. In a preferred aspect of the invention, there is provided a device for keeping track of passwords comprising a first surface marked with a pseudo random binary 30 sequence arranged in a ring and at least one ring comprising characters and a plurality of windows, aligned with bits of the pseudo random binary number; and a second surface defining at least one ring of characters disposed for rotation behind the first surface such that at least some of the characters in the at least one ring of the second surface are visible through the windows; and 35 a means for determining the relative rotational alignment of the first and second surfaces.

WO 2008/061302 PCT/AU2007/001787 4 Alternatively, the pseudo random binary sequence arranged in a ring may be defined on the second surface and a window defined on the first surface such that the PRBS is visible when the second surface is disposed behind the first. Typically, the means for determining the relative rotational alignment of the 5 first and second surfaces comprise a single window in the first surface and a ring of alignment characters on the second surface, disposed/disposable so that one of those characters is visible through the window when the surfaces are in a particular relative rotational alignment. Preferably, there are 32 characters in the ring of alignment characters to define 32 different possible relative rotational alignment of the first and 10 second surfaces. The first surface may be the front face of an envelope, with the second surface being a card or sheet which locates inside the envelope between the front face and a rear face. Most preferably the ring comprising characters and a plurality of windows, 15 includes windows of differing widths and characters arranged in groups of up to five contiguous characters. Most preferably the ring is arranged as a PRBS. A second ring and a corresponding second ring on the second surface may be provided adjacent the first rings of the first and second surfaces, respectively. A yet further aspect of the present invention provides a device for keeping track 20 of passwords comprising: a first ring having at least one first edge and a surface, wherein a first array of indications representing binary ones or binary zeros extend along or adjacent to one edge of the ring, and wherein a series of characters are marked on the surface of the ring in positions generally corresponding to a location of the indications representing 25 binary ones or zeros; and a second ring having at least one first edge and a surface, wherein a second array of indications representing binary ones or binary zeros extend along or adjacent to one edge of the ring, and wherein a series of characters are marked on the surface of the ring in positions generally corresponding to locations of the indications representing 30 binary ones or zeros; and wherein the edges of the rings may be juxtaposed and the first and second arrays of indications representing binary ones or binary zeros may be combined in a predetermined arrangement to define a pseudo random binary sequence (PRBS). In one embodiment indications may be provided on both edges of each ring with 35 the indications on the second edges of each ring each defining a complete PRBS.

WO 2008/061302 PCT/AU2007/001787 5 The rings are preferably visually distinguished from one another by colour markings or some other means. The indications may be defined by notches and blanks or in any other suitable manner. 5 Typically, both edges of the ring are divided into 2" equally spaced positions. Most preferably n is 5, so that there are thirty-two positions. This is typically the maximum number of positions that comfortably fit around a ring sized to fit a human finger. For the indications on the second edges an equal number of blanks and notches (2" of each) are arranged as a pseudo random binary sequence (PRBS) around the ring 10 where a blank represents "0" and a notch represents "1". The first edges will also typically have 32 bits so that the combination of the first edges create a 64 bit PRBS. The outer surface of the ring, may have any number of rows of characters arranged around the circumference of the ring. Alternatively, the characters may be 15 arranged around the inner surface of the ring so that they are not visible when the ring is being worn, or such characters may be provided on both inner and outer surfaces. Possible arrangements include 2" characters in each row, with each character aligned with the notches or blank positions defined around the edge of the ring. Alternatively, a staggered arrangement may be provided between two rows, to 20 allow for larger font size letters, where in one row, each successive character is aligned with every second edge position, and the accompanying row has the characters aligned with the "in between" edge positions from the first row. The present invention also embraces particular methods and protocols for using the rings which are described in more detail in the detailed description. 25 Brief Description of the Drawings Specific embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which: Figure 1 illustrates a 64 binary digit PRBS separated into two subset binary 30 sequences of alternate digits; Figure 2 is a representation of a ring cut and laid flat including edge markings comprising a 32 bit PRBS and having corresponding surface characters; Figure 3 shows two similar rings to that shown in Figure 2, having characters and edge markings where the adjacent edges of the two rings have the subset binary 35 sequences derived from the 64 bit length PRBS shown in Figure 1; WO 2008/061302 PCT/AU2007/001787 6 Figure 4 illustrates the two rings shown in Figure 3 but with the ring positions swapped; Figure 5 illustrates the reading of five digits at a time from a PRBS; Figure 6 is a table showing 32 ten bit numbers generated from the alignment of 5 the binary representation of 22 (10110) on the 32 bit length PRBS on an edge shown in Figure 4 in every position relating to the PRBS on that edge; Figure 7a shows a first sheet marked with a circle comprising a 16 bit PRBS; Figure 7b shows a second circle formed from a sheet of transparent material with a larger circle marked with a different 16 bit PRBS; 10 Figure 8 shows the circle of Figure 7b superposed on the circle of Figure 7a; Figure 9a shows a first or bottom card of a further embodiment of the invention; Figure 9b shows a second or top card of the further embodiment of the invention; Figure 10 shows the second card superposed on the first; 15 Figure 11 shows a first component, in the form of an envelope of a yet further embodiment of the invention; Figure 12 shows a contents card which locates inside the envelope of Figure 11; Figure 13 illustrates the contents card of Figure 12 inside the envelope of Figure 11; 20 Figure 14 illustrates a variant of the envelope of Figure 11; and Figure 15 illustrates a variant of the contents of card of Figure 12. Detailed Description of Preferred Embodiments. Referring to the drawings, Figure 1 shows a 64 bit length pseudo random binary 25 sequence (PRBS) 10. Although the Figure shows the PRBS as a series of "O"s and "1"s when defined on a ring, to be worn as jewellery or the like, a "1" may be represented by a notch in the edge of a ring and a "0" by the absence of a notch. A pseudo random binary sequence (PRBS) is a known phenomenon. A key property is in the sequence of 2"n binary Is and Os, where a frame of n binary Is and 0 30 but where a frame of n consecutive positions placed over the sequence represents an n bit binary number. Shifting the read frame by one position yields a different n bit binary number. There are 2" unique read frames and by definition, the PRBS of blanks and notches means all numbers between 0 and 2" are represented in a seemingly random order, each number represented only once. Importantly, each reading frame 35 produces a unique binary number and no binary number is repeated. Programmes and information for generating PRBSs are readily available. Although when in a ring, the WO 2008/061302 PCT/AU2007/001787 7 binary numbers are typically represented by notches and blanks, it will be appreciated that other representative symbols could be used including the numerals "1" and "0". A PRBS can be separated into two subset sequences of the alternate digits in the sequence (the odd and even positions in the sequence). This is illustrated in Figure 1 5 for a 64 bit long sequence, where two 32 bit sequences are shown, one (12) comprising every second digit (the digits in even numbered positions) and the other (14) comprising the remainder of the digits (the digits in odd number positions, e.g. the first, third, fifth etc). For a few PRBS sequences, one of the subsets is a PRBS, more commonly neither of these subset sequences is a PRBS. There is only one alignment of 10 the two subset sequences 12, 14 that re-establishes the original PRBS. Thus the subset sequences 12, 14 can be used on the adjacent edges of two rings, and when the two rings are aligned in one, and in only in one position, the 64 length PRBS is re-established. If the two rings each have 32 character positions on the outer surface, preferably 15 two rows with characters offset relative to one another to improve readability, one edge could contain a 32 bit length PRBS which can be used to identify each character position on its own ring. Figure 2 represents such a ring 20 which has a PRBS 22 and two offset/staggered rows 24, 26 of characters. If for example, we take the read frame shown by the box in Figure 2, this gives a binary number 11010 which converts to 26 20 in decimal. The user might therefore record the number 26 as the relevant number for a password. This would signify the unique read frame on the edge of the ring where there are two consecutive notches, a blank, a notch and a blank i.e. 11010. There is only one such position on the edge of the ring. The user might use the convention that they read the character on the surface of the ring that corresponds to the first notch in 25 its position 24, and the numeral 6 could be used to remind the user to read six successive characters in a predetermined arrangement starting from the character aligned with the first of the five consecutive notches. Thus in the example shown in the ring Figure 2, the codeword "26, 6" would convert to the six characters adjacent the first notch in the sequence 11010 resulting in the codeword "klmnop". Of course, in a 30 typical embodiment, the characters would be likely to be mixed somewhat and interspersed with numeral and symbols to make the password more difficult to crack. Figure 3 shows two paired rings 30, 40 defining characters and edge markings. The adjacent edges 32, 42 have the subset binary sequences 12, 14 from the 64 bit length PRBS. The outer edges simply have a 32 bit length PRBS 34, 44 respectively 35 similar to that shown in Figure 2. Again in both rings there are two offset rows 36, 38, WO 2008/061302 PCT/AU2007/001787 8 46, 48 of surface characters which would typically be less predictably arranged, and would be include numbers and symbols. With reference to the orientation of the rings shown in Figure 3, if the uppermost ring 30 is moved by half a character to the right, the PRBS 10 identified in 5 Figure 1 is re-established starting with the first bit (0) on the lower ring 40 then reading the first bit (0) on the upper ring, the second bit (0) on the lower ring, the second bit (0) on the upper ring etc... Thus the two rings 30, 40 together in such a slightly offset alignment have a unique readily identified alignment defined by the subset sequences on the adjacent edges of 64 characters on the outer edge of the ring, and the surface 10 characters could then be read across the two rings specifically AaBbCc etc. With the rings together in the slightly offset alignment creating the 64 bit PRBS, the 64 bit PRBS 10 may be used as a basis for providing passwords, in a similar manner to that described above in relation to the ring shown in Figure 2. More complex arrangements are described below. 15 The ring positions can be swapped so that the edges defining the 32 bit PRBSs 34 and 44 are adjacent. This is illustrated in Figure 4. The 32 bit PRBS can be read in a five digit frame which each of the 32 frame positions around the ring representing all the decimal numbers between 0 and 31. In the case of the 32 bit length PRBS 32 positions and decimal representations are shown in Figure 5. 20 With the ring alignment shown in Figure 4, a read frame for the number 22 the uppermost ring 40 is identified by the frame 50. The first digit in this read frame corresponds with the "I" surface character on the surface of the ring 40. If then ring 30 (the lower ring in Figure 4) is given a half character offset to the right a ten digit binary number is generated comprising the digits in the frame 50 interspersed with the digits 25 in the frame 52 below. Starting at the read frame on ring 40 reading the first digit in frame 50, then the first in frame 52 then the second in frame 50, then the second in frame 52 and so on gives "1001111100". This binary number has a decimal number of 636. This same alignment of the two rings can be identified by any of 32 ten digit binary sequences, generated from the alignment of ring 40 to ring 30 of the 32 five bit 30 read frames on RI. Alternatively, a 5 bit read frame on one ring can be aligned in 32 positions relative to the other, also generating 32 ten digit binary sequences. In the case of the frame for 22 on ring 40, it will generate the thirty-two numbers shown in the table of Figure 6. These two ways to designate the alignment of the two rings (the 32 35 representations for each of the 32 positions 32^2) will generate all 1,024 (2^10) numbers between 0 and 1023.

WO 2008/061302 PCT/AU2007/001787 9 Two rings made in the manner similar to Figure 3, and aligned in either of the two ways identified in Figure 3 or 4, may be used to generate passwords that can be encoded, and recorded using a decimal number code that can be deciphered according to a prescribed and reproducible protocol. That is the deciphered code provides an 5 indication of where to read the characters on the surface of the ring that represents a particular password. The protocol would encompass the following parameters. 1. Specify whether one ring or two rings is used. The prototype rings may be made in white and yellow gold so that they are readily identified or may be distinguished in some other way; 10 2. Specify which of the two rings, or in which alignment the two rings in combination are used. Alignment can be specified by a number that is derived from the 64 bit PRBS shared between the two edges, or a number derived from a ten bit binary digit sequence (with 31 alternatives that could specify the same alignment); 3. Specify the start position on the ring to begin reading the surface 15 characters; 4. Specify or identify the pattern of reading the characters (forward, backward, both rows on one ring, all four rows on both rings, one row on one ring, etc); 5. Specify the length of the character sequence. With reference to Figure 4, A protocol such as 2 (both rings), 636 (alignment of 20 the 32 bit length PRBSs edge to edge), 0 (start position offset), 4rf (four rows of characters read forwards), 10 (the number of characters) would yield the password IiJjKkLlMm. I.e. the encoded record 2,636,0,4rf, 10 = IiJjKkLlMm. Using the 64 bit sequence on the adjacent edges, which also specifies the two rings, the number 45 (101101) indicates the position to start reading the ring. Thus, 25 45,10 would signify the same password. If a standard protocol is used for the number of rings used, the alignment, pattern of reading characters, and the number of characters, a password could be represented by a single decimal number to remind the user where to start reading the characters. If the user of the password rings always used the 64 bit edges aligned 30 together, and always used ten character long passwords, the number 45 would be all that need be recorded. A further embodiment of the invention is illustrated in Figure 7 which relies on pairs of circles operating on similar principals to the rings with the pair of circles used separately or together.

WO 2008/061302 PCT/AU2007/001787 10 A circle defining eg a 16 bit PRBS is marked on the card. A series of characters are marked on the card aligned with the "1"s and "O"s of the PRBS. One of the unique set of notch and blank sequences is also marked adjacent to the circle. For example, for a four bit binary number which can represent the numbers 5 between 0 and 15, inclusive, a single notch could represent 1, 2, 4 or 8 (i.e. 0001, 0010, 0100, 1000), two adjacent notches could represent 3, 6 or 12 (0011, 0110, 1100), two notches separated by a space represents 5 or 10 (0101, 1010), two notches separated by two spaces is 9 (1001), three notches together represents 7 or 14 (0111, 1110), two notches, a space then a notch can be either 11 or 13 (1011, 1101), and four notches 10 represents 15 (1111). Two circles of different sizes, each with notches and associated characters can be combined, one on a transparent background, so that a similar encoding device is created. With reference to Figure 7a, a card 60 has marked on it a 16 bit PRBS 62 with "1 "s represented by notches or lines and "0's by blanks, in a circle with a ring of 16 15 characters 64 arranged outside and adjacent to the circle, aligned with each notch or blank position on the PRBS on the ring. A single alignment mark 66 adjacent to the letter "E" can be used to signify either the decimal number 1, 2, 4 or 8 in four bit binary form, (i.e. 0001, 0010, 0100, 1000) as described above. 20 Similarly, a card 70 shown in Figure 7b defines a larger circle 72 with a different PRBS and in which a row of characters 74 internal to the circle are shown. Alignment marks 68 adjacent to the characters "Y" and "W" Two adjacent notches can be used to represent the decimal values of 3, 6 or 12 (0011, 0110, 1100). One of the cards (either that shown in 7a or 7b) can be printed on a transparent medium and 25 overlayed on the other so that the two circles are concentric, giving the arrangement shown in Figure 8. The circle in the upper transparent card can be rotated into sixteen positions where its notches and characters are overlayed and the notches and characters of the lower card, and aligned so that the characters are staggered. 30 The total of 32 characters are then aligned in a sequence. The position of the two rings relative to one another can be defined by the alignment mark of one card with the circle bearing the PRBS from the other. Unique positions are defined by the resultant eight bit length sequence when the four binary positions of the alignment marks 66, 76 are combined with the four interleaved, adjacent bits of the PRBS from 35 the other card. In other words, the unique eight bit binary number formed by WO 2008/061302 PCT/AU2007/001787 11 combining the alignment marks can be used to define the relative alignment of the cards to be used when reading or encoding a password. Figures 9a to 10 show a yet further embodiment in which a top card or disc 80 (shown in Figure 9b) can be superposed on and rotated relative to a second or lower 5 card 90 (shown in Figure 9a). The top card 80 defines a ring of characters 82 adjacent a PRBS formed in a ring along the outer edge of the card, with through holes/perforation 84 defined between each pair of characters in the ring 82. The perforations 84 act as a window so that when the top card is superposed on the lower card 90 characters on the lower card can be read. 10 More specifically, the lower card 90 has a ring 92 of 16 characters evenly spaced, so they will appear in the windows 84 of the upper card when the upper card is superposed on the lower card (see Figure 10). The lower card has one, two, three or four notches 94 in a section of a loop outside the ring 92 and visible beyond the border of the upper card when the upper card is superposed on the lower card. These notches 15 could be aligned with the PRBS on the upper card in a similar way to that possible with the cards described above in relation to Figures 7a to 8. On the upper card, a set of four windows 86, in an arc, spaced as though they were the four spaces between 5 characters (of a total of 16 evenly spaced in a loop), would be made more central on the card, concentric with the edge and characters. The 20 lower card would has a 16 bit length PRBS 96 arranged in a circle, aligned so that four digits of the PRBS 96 could be read through these windows 86. Any combination of one, two or three or four notches could be used relative to the windows on the upper card, and thus a variety of 8 bit length sequences can be generated from the 16 different positions that arise by rotating the top card relative to the bottom. 25 Figures 11 to 13 show a yet further variant of the invention. Figure 11 shows an envelope 100 comprising a front sheet 102 and a rear sheet (not shown). The envelope card defines an outer ring 104 and an inner 106 ring of symbols/characters and windows. As with the previously described embodiment, the characters may be any combination of letters, numbers, symbols etc.. However, in contrast with the 30 embodiment shown in Figures 9a to 10, the windows in the inner and outer rings are arranged using a binary PRBS. That is, instead of a character followed by a window followed by a character, etc., there are a variety of arrangements. In the PRBS a window may represent "0" and a character "1", or vice versa. There are four single character width windows 108 , two double character width windows 110, one triple 35 width window 112 and one quintuple width window 114. The characters are similarly grouped - four singles, two pairs, and one each of five and three.

WO 2008/061302 PCT/AU2007/001787 12 Inside the inner ring 106 of characters, there is a PRBS ring 116 of dots (representing Os) and Is. Just inside that ring there is a single positioning window 118. Figure 12 shows a contents card 120 which locates inside the envelope. The card defines an outer 122 and inner 124 ring of characters extending around its centre 5 125. There is also an innermost ring 126 of characters in which no character is repeated. As discussed below this ring, in conjunction with the single window 118, is used to position the contents card, when rotated in the envelope into one of 32 unique positions. With reference to Figure 13, the contents card 120 is inserted in the envelope 10 100 and fixed at its centre 125 to rotate like a pinwheel inside the envelope. Figure 13 shows the contents card rotated/positioned so that the "3" of the innermost ring 126 is visible in the positioning window 118 of the envelope. There is an outer 140 and inner 142 ring. The outer ring 140 comprises 32 characters made up of the characters of the outer ring 104 of the envelope and those characters of the outer 15 ring 122 of the contents card which are visible through the windows of the outer ring. Similarly the inner ring 142 comprises 32 characters made up of the characters of the inner ring 106 of the envelope and those characters of the inner ring 124 of the contents card which are visible through the windows of the inner ring 106. That "3" uniquely defines the relative positions of the contents card 120 inside the envelope. 20 Alternatively, as illustrated in Figures 14 and 15, larger font can be used with 16 instead of 32 characters, arranged so any consecutive two characters uniquely defines each of the 32 positions. It will be appreciated that rotating the contents card will define another unique position and that, with 32 different characters in the innermost ring, or 16 characters read in pairs, there are 32 possible positions. Each different 25 position produces a different combination of characters visible on the outer and inner rings. This arrangement provides a desirable fixation of the contents card relative to the envelope allowing rotation only of the contents card, within the envelope card. The variation in the size and spacing of the windows and characters on the envelope allow a 30 much greater variation in combining characters and make any codes generated by the device much more difficult to crack. The card can be used to encode in a similar manner to the previously described embodiments, using one of a number of possible protocols. The character shown in the window needs to be recorded. After that, similar protocols to those used on the ring 35 (see page 7 lines 6 to 23) could be used with a number between 0 and 31 identifying a location on the binary PRBS 116 and a second number indicating how many characters WO 2008/061302 PCT/AU2007/001787 13 to take. For example, 3, 31,6 could indicate the six characters following the first digit of the binary 31 in the PRBS i.e. "q049j6". The characters may be any type of visual symbol or device such as letters from any written language, numerals from any written language or even symbols which have 5 no literary or numeric meaning, although for practical reasons as most passwords are used with computers it is best to provide characters which will be typically provided on the keyboard of a computer. It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific 10 embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims (22)

1. A device for keeping track of passwords comprising; a first surface marked with a pseudo random binary sequence arranged in a loop and a series of characters aligned with bits of the pseudo random binary number; and 5 a second surface also marked with characters arranged in a loop/ring; wherein at least one of the first or second surface is at least partly transparent or defines transparent areas or windows such that it may be superposed on the second or first surface respectively with characters of that second or first surface visible through the windows/transparent areas of the other surface and generally aligned with bits of the 10 pseudo random binary sequence; and a means for indicating the relative alignment of the superposed surfaces.

2. A device as claimed in claim I wherein the loops comprise circles and the first and second superposed surfaces may be rotated relative to each other about the centre of the circles. 15

3. A device as claimed in claim 1 or claim 2 wherein the pseudo random binary sequence is a 16 bit or 32 bit binary sequence.

4. A device as claimed in any one of claims 1 to 3 wherein the first surface is at least partly transparent or defines transparent areas or windows and is superposed on the first surface. 20

5. A device as claimed in claim 4 wherein the first surface defines a series of windows.

6. A device as claimed in any one of claims I to 5 wherein the first and second surfaces are planar and are defined by a sheet of material such as cardboard, plastic, laminate, or any other suitable material. 25

7. A device for keeping track of passwords comprising a first surface marked with at least one ring comprising characters and a plurality of windows, aligned with bits of the pseudo random binary number; and a second surface defining at least one ring of characters disposed for rotation behind the first surface such that at least some of the characters in the at least one ring 30 of the second surface are visible through the windows; a pseudo random binary sequence arranged in a ring and either disposed on the first surface or disposed on the second surface and visible through the second surface; and a means for determining the relative rotational alignment of the first and second 35 surfaces. WO 2008/061302 PCT/AU2007/001787 15

8. A device as claimed in any one of claims 1 to 7 wherein the means for determining the relative alignment of the first and second surfaces comprises a further window in the first surface and a ring of alignment characters on the second surface, disposed so that one of those characters is visible through the further window when the 5 surfaces are in one relative rotational alignment, and when the first surface is rotated relative to the second surface, different characters become visible through the further window, dependant on the relative rotational alignment of the first and second surfaces.

9. A device as claimed in claim 8 wherein there are 32 characters in the ring of alignment characters to define 32 different possible relative rotational alignment of the 10 first and second surfaces.

10. A device as claimed in any one of claims 1 to 9 wherein the first surface is defined by a front sheet of an envelope with the second surface being a card or sheet which locates inside the envelope between the front face and a rear face of the envelope. 15

11. A device as claimed in any one of claims 7 to 10 wherein the ring comprising characters and a plurality of windows includes windows of differing widths and characters arranged in groups of up to five contiguous characters.

12. A device as claimed in claim 11 wherein the ring is arranged as a 32 bit PRIBS with the characters representing binary Is and the windows binary Os. 20

13. A device as claimed in any one of claims 8 to 12 wherein a second ring comprising characters and a plurality of windows and a second ring of characters is provided on the second surface adjacent the first rings of characters of second surface.

14. A device for keeping track of passwords comprising: a first ring having at least one first edge and a surface, wherein a first array of 25 indications representing binary ones or binary zeros extend along or adjacent to one edge of the ring, and wherein a series of characters are marked on the surface of the ring in positions generally corresponding to a location of the indications representing binary ones or zeros; and a second ring having at least one first edge and a surface, wherein a second array 30 of indications representing binary ones or binary zeros extend along or adjacent to one edge of the ring, and wherein a series of characters are marked on the surface of the ring in positions generally corresponding to locations of the indications representing binary ones or zeros; and wherein the edges of the rings may be juxtaposed and the first and second arrays of indications representing binary ones or binary zeros may be 35 combined in a predetermined arrangement to define a pseudo random binary sequence (PRBS). WO 2008/061302 PCT/AU2007/001787 16

15. A device as claimed in claim 14 wherein indications are provided on both edges of each ring with the indications on the second edges of each ring each defining a complete PRBS.

16. A device as claimed in claim 14 or 15 wherein the rings are visually 5 distinguished from one another by colour, markings or some other means.

17. A device as claimed in any one of claims 14 to 16 wherein the indications are be defined by notches and blanks or in any other suitable manner.

18. A device as claimed in any one of claims 14 to 17 wherein both edges of the ring are divided into 2" equally spaced positions. 10

19. A device as claimed in claim 18 where n is 5.

20. A device as claimed in any one of claims 14 to 19 wherein the outer surface of the ring defines at least one of row of characters arranged around the circumference of the ring.

21. A device as claimed in any one of claims 14 to 19 wherein the characters are 15 arranged around the inner surface of the ring so that they are not visible when the ring is being worn, or such characters may be provided on both inner and outer surfaces.

22. A device for keeping track of passwords substantially as hereinbefore described with reference to Figures I to 6, or &a to 8, or 9a to 10, or 11 to 13 or 14 and 15 of the accompanying drawings.