EP0171323A1 - Operating and controlling system for a plurality of accesses equipped with coded locks - Google Patents

Abstract

The invention relates to an installation for command and control of the different coded locks of an assembly comprising: a transmitter capable of developing coded keys for controlling said locks and a reader associated with each lock, capable of unlocking this lock on simple presentation to the latter of a correctly coded key, this transmitter and this reader being arranged in such a way that the detection by said reader of the code y recorded by said transmitter on each new key of order p assigned to the lock associated with this reader is translate by the invalidation of the code x recorded on the order key p-1 previously assigned to this lock, each code y being deducible from the code x by an algorithm y = f (x) stored in memory at least in the transmitter . At each instant the reader is simultaneously sensitive to a number m greater than two of non-invalidated codes of the sequence x, f (x), f² (x), ..., f <n> (x) and is arranged so such that by reading any of these codes, it automatically invalidates all the lower rank codes of the sequence considered.

Description

The invention relates to installations for command and control of the different coded locks of an assembly comprising a relatively large number of such locks, this number preferably being greater than 50 and even more than 100.

It concerns more particularly, because it is in their case that its application seems to offer the most interest, but not exclusively, among these installations, those equipping hotels comprising a large number of rooms, each of these rooms being accessible by a door fitted with a coded lock, which lock is electrically controllable using a corresponding coded key.

The coded keys in question are preferably cards carrying a code recorded in magnetic or optical form, or even portable transmitters of codes in the form of electromagnetic or ultrasonic waves, and the codes considered are numbers expressed by sequences binary signals.

The coded keys may also consist of an intangible code intelligibly entrusted to an authorized user, for example in the form of a series of numbers and / or letters, and intended to be composed on a keyboard arranged near the lock or to be reproduced in any other desirable manner.

In installations of the type indicated, the persons authorized to unlock a given lock are only provisional and change frequently.

It must therefore be avoided that a malicious user can continue to unlock the lock in question beyond the expiration of the period during which he held the authorization, and this using a copy of the key which had been entrusted to him then or using this key itself, kept by him beyond said expiration.

To obtain such a result, it has already been proposed to automatically invalidate the key assigned to each lock by simply presenting this lock with a new key held by the next authorized user.

In certain known embodiments of installations designed for this purpose, the code assigned to each key by a central key transmitter comprises two portions recorded respectively on two distinct areas of the key, namely a first portion directly assigned to unlocking the lock and a second portion assigned to the code change.

To simplify, hereinafter "first key" will mean a key entrusted to a first user authorized to unlock a given lock and "second key" a key entrusted subsequently to a second user whom we wish to empower in turn. deleting the authorization of the first, and the code portions recorded by the central key transmitter on the two ranges of the first key will be designated by A and B respectively and by B 'and C the code portions recorded respectively on the two second key ranges.

In the known embodiments, the codes B and B 'are identical.

The lock concerned originally comprises means for controlling its unlocking on reading the partial code A on the first range of a key, means for storing the partial code B carried on the second range of such a key carrying the partial code A on its first range, and means of comparison.

As long as the first correct key is presented to the lock, the reading of the partial code A of its first range directly ensures the unlocking of this lock and the partial code B only intervenes by its storage.

When presenting the second key, the unlocking section of the lock no longer reads the correct partial code A on the first range of this key, but the partial code B.

This is where the comparison means of the lock come into play: these compare the partial code (here B) previously stored in memory coming from the second range of the first key with the new partial code read on the first range of the second key.

The identification resulting from such a comparison has the effect of unlocking the lock, of making this lock adopt the code thus identified, that is to say here the partial code B, as the new unlocking code and of invalidating , by erasure or otherwise, the partial code A of initial unlocking.

It is then the partial code C of the second range of the second key which ensures the role of the previous partial code B, and so on.

Such a formula - which has been the subject, in particular, of US patents No. 3,821,704, No. 3,860,911, No. 4,207,555 and No. 4,213,118 has the important advantage of allowing automatic invalidation of the keys. expired by the simple subsequent use of valid keys without the need for other local interventions.

But it is not immune to fraud.

Indeed, it is relatively easy for a malicious user who succeeds in being entrusted with two successive authorization keys assigned to the same lock to detect by comparison between the codes recorded on these two keys the partial code common to them, know B in the example above; and therefore to deduce therefrom the partial unlocking code (here C) of the next key of the series corresponding to the lock considered and to establish itself such a following key without the knowledge and in place of the transmitter central keys.

This next key, although "falsely" issued, allows the lock considered to be unlocked as well as the next "real" key.

To benefit from the advantage indicated above while making the fraud just indicated impossible, it has been proposed, in a command and control installation further comprising, as previously, a transmitter capable of developing coded keys for controlling locks and a reader associated with each lock, capable of unlocking this lock upon simple presentation to the latter of a correctly coded key , this transmitter and this reader being arranged in such a way that the detection by said reader of the code y recorded by said transmitter on each new order key p assigned to the lock associated with this reader results in the invalidation of the code x recorded on the order key p-1 previously assigned to this lock, to make each code y deductible from code x by an algorithm y = f (x) stored in memory at least in the transmitter.

By "algorithm" in the present text is meant a set of numerical operations corresponding to a first number x a second number y.

Each of the transmitter and reader devices is then equipped so as to exploit the algorithm appropriately.

Thus the transmitter working out the successive keys intended to unlock the lock equipped with the reader in turn is arranged so as to register respectively on these successive keys the codes x, f (x), _f ² ( _x ) _{... f} ⁿ ( _x ) _...

et le symbole f(x) est équivalent àIn the previous paragraph, n denotes an integer, f ⁿ (x) means f ¹ (x).

and the symbol f (x) is equivalent to

As for the reader associated with the lock considered, it is arranged so as to compare successively the codes read on the different keys with the codes x, f (x), f ² (x), ..., f ⁿ (x). .. and to unlock the lock when the comparison made reveals an identity.

In addition, the reader is equipped with means for automatically invalidating each code f ^P (x) when the key bearing the code f ^{p + 1} (x) is presented to it.

Under these conditions, each reader-lock sub-assembly is arranged in such a way that at a given moment the lock can be unlocked by presenting to the reader one or the other of two codes f ^P (x) and f ^{p + 1} (x), the presentation of the first of these two codes resulting in the only unlocking of the lock while the presentation of the second code results not only in this unlocking, but also in the invalidation of the first code and by raising awareness of the reader to the following code fp + 2 (x) of the series, the roles played respectively just before this presentation of the second code f ^{p + 1} (x) by the first two codes being played respectively from this instant by the two codes fP ⁺¹ (x) and f ^{p + 2} (x).

In the known embodiments of such an installation, each reader is sensitive at each instant to only two codes, namely the codes fP (x) and fP ⁺¹ (x) in the above example.

Such a formula requires rigorous synchronization between the transmitter and each reader.

It may indeed happen that a "first key" produced by the transmitter intended for a given lock is not actually used before the preparation of the next key or "second key" by said transmitter.

The result of such a failure to use a progression failure in the series of codes readable by the reader associated with said lock, which makes said "second key" inoperative for opening this lock.

This drawback is particularly manifest when each of the keys considered is authorized to open a plurality of locks: in such a case, it may happen that at least one of said locks was not actually actuated by the "first key "corresponding during the authorization period of this key.

The invention overcomes this drawback.

For this purpose each reader is made sensitive to each that instant at a number m greater than two of codes not invalidated from the sequence of codes f ^p (x), f ^{p + 1} (x), f ^{p + 2} (x) ... deductible from each other by the f (x) algorithm.

This reader is then arranged in such a way that by reading any of the valid codes of this sequence, it automatically invalidates all the codes of lower rank of said sequence.

Under these conditions, the lock associated with said reader can be opened at any time by the last key produced by the transmitter intended for this lock.

The number m is chosen according to the real risk presented by the defect indicated above: it is preferably between 5 and 100, being for example of the order of 10.

The different codes of the suite in question can be recorded in advance in a memory of the reader concerned, the number of these valid codes gradually decreasing due to the successive invalidations of the keys.

Such a solution certainly has the advantage of making the real local exploitation of the algorithm f (x) unnecessary, but it requires chronically recharging the memory of the reader.

In all cases the reader can be equipped with means for counting and recording the number of code changes which have occurred since the origin of the life of the lock or since a determined instant of reset.

According to an interesting embodiment, the algorithm y = f (x) adopted for all the readers is the same, but the starting code x, of the sequence x, f (x), f ² (x) ... , f ⁿ (x) ..., which is initially assigned to unlocking each lock, differs from those initially assigned to other locks.

• l'identification du premier code, de cette suite, valide à un instant donné peut alors être obtenue par le simple comptage , évoqué

In such a case, the appropriate code suite can be saved as previously in a memory of each reader:

• the identification of the first code, of this sequence, valid at a given time can then be obtained by simple counting, mentioned

above, of the number of code changes that have occurred since a given start time, which may be a reset time, counting of course supplemented by knowledge of the start code assigned to the lock concerned.

This solution also simplifies the construction of the transmitter since it uses a single algorithm in all and for everything for the establishment of all the keys.

This simplification is very important since, for example for the application of the invention to the service of a hotel with 100 rooms, it amounts to dividing by 100 the number of algorithms recorded in the transmitter as well as the number of circuits corresponding calculation and transformation.

The counterpart of this simplification - knowing the need to correctly identify the different starting codes assigned to the different locks and the numbers of subsequent code changes - only removes a small part of the advantage thus obtained.

Following which, and whatever the embodiment adopted, there is finally an installation for command and control of the different coded locks of a set, the constitution and operation of which result sufficiently from the above.

This installation has a number of advantages over those previously known.

• - elle rend impossibles les fraudes signalées : en effet, l'utilisateur mal intentionné qui réussirait à se faire confier deux clés successivement habilitées au déverrouillage d'une serrure donnée peut certes en déduire les deux codes x et y enregistrés respectivement sur ces deux clés, mais il ne pourra pas en déduire l'algorithme f(x) qui relie ces deux codes car le nombre d'algorithmes reliant deux nombres entre eux est infini : il ne pourra donc pas élaborer "faussement" une clé suivante de la série concernée
• - la richesse de chaque code de déverrouillage enregistré sur une clé donnée est très supérieure à celles des codes partiels desdites installations antérieures du fait que la plage disponible pour l'enregistrement de ce code sur chaque clé est deux fois plus grande.

In particular, compared to the previous installations of the first type mentioned in the introduction,

• - it makes reported fraud impossible: indeed, the malicious user who succeeds in being entrusted with two keys successively authorized to unlock a given lock can certainly deduce the two codes x and y recorded respectively on these two keys, but it will not be able to deduce the algorithm f (x) which connects these two codes because the number of algorithms connecting two numbers between them is infinite: it will therefore not be able elaborate "falsely" a following key of the series concerned
• - The richness of each unlocking code recorded on a given key is much greater than that of the partial codes of said previous installations because the range available for recording this code on each key is twice as large.

Compared to the previous installations of the second type mentioned in the introduction, the installation proposed here overcomes the servitudes of "synchronization" between the transmitter and the readers, the absence of use of certain "first keys" no longer reflected here by the neutralization of the corresponding "second keys".

As is obvious, and as already follows from the foregoing, the invention is in no way limited to those of its modes of application and embodiments which have been more especially envisaged; it embraces, on the contrary, all variants, in particular those where the algorithm allowing to develop the code y from the previous code x would be a function not only of this previous code, but also of a number assigned to the set lock-reader concerned, number recorded both in this set and in the transmitter, in particular in the case where the number of said sets is particularly high.

Claims (5)

1. Installation for command and control of the various coded locks of a set, comprising: a transmitter capable of developing coded keys for controlling said locks and a reader associated with each lock, capable of unlocking this lock upon simple presentation to the latter ci of a correctly coded key, this transmitter and this reader being arranged in such a way that the detection by said reader of the code y recorded by said transmitter on each new key of order p assigned to the lock associated with this reader results in the invalidation of the code x recorded on the order key p-1 previously assigned to this lock, each code y being deducible from the code x by an algorithm y = f (x) stored in memory at least in the transmitter, characterized in that at each instant the reader is simultaneously sensitive to a number m greater than two of non-invalidated codes of the sequence x, f (x), _f ² ( _x ) ...., _f ⁿ (x) and is arranged so that by reading any of these codes, it automatically invalidates all the lower rank codes of the sequence considered. 2. Installation according to claim 1, characterized in that the number m is between 5 and 100. 3. Installation according to any one of the preceding claims, characterized in that the reader is equipped with means for counting and recording the number of code changes which have occurred since a start or reset time. 4. Installation according to any one of the preceding claims, characterized in that one and the same algorithm is adopted for the different locks, the codes assigned to unlocking these different locks at each instant differing from one another due to the choices different adopted for the respective starting codes. 5. Installation according to any one of the preceding your claims, characterized in that the algorithm making it possible to develop the code y from the previous code x is a function not only of this previous code, but also of a number assigned to the lock-reader unit concerned, recorded number both in this set and in the transmitter.