Method for being capable of carrying out, with the same data carrier, various authentication processes, as well as system

Known methods for being capable of carrying out, with the same data carrier, various authentication processes are based on non-standardized data carriers (smart cards) on which there are stored two different access codes. Per first authentication process, a first user generates a first user code which is compared to a version, transformed by way of a transformation, of a first access code stored on the data carrier. Per second authentication process, a second user generates a second user code which is compared to a version, transformed by way of the transformation, of a second access code stored on the data carrier. By now having the transformation in this case take place, per other authentication process, by way of another transformation, there may be used, for different authentication processes, the same worldwide standardized data carrier on which there is stored only one access code. The first/second user then once again generates the first/second user code, which is compared to a version transformed by way of a first/second transformation of the only access code stored on the data carrier.

Method for being capable of carrying out, with the same data carrier, 
various authentication processes, as well as system. 
BACKGROUND OF THE INVENTION 
The invention relates to a method for being capable of carrying out, with 
the same data carrier, various authentication processes, on which data 
carrier there is stored at least one code, which method in the event of a 
first authentication process comprises the steps of 
receiving a first code stored on the data carrier and a second code 
originating from a user, 
carrying out at least one of the following transformations 
a first transformation of the first code into a transformed first code, and 
a second transformation of the second code into a transformed second code, 
comparing codes for in response thereto rounding off the first 
authentication process, and which method in the event of a second 
authentication process comprises the steps of 
receiving a third code stored on the data carrier and a fourth code 
originating from a user, 
carrying out at least one of the following transformations 
a third transformation of the third code into a transformed third code, and 
a fourth transformation of the fourth code into a transformed fourth code, 
comparing codes for in response thereto rounding off the second 
authentication process. 
Such a method is disclosed in U.S. Pat. No. 4,837,422. Herein, there is 
shown a data carrier constructed as smart card (FIG. 2 of U.S. Pat. No. 
4,837,422) on which there is stored a first code (a PIN code stored in 
memory 210 in FIG. 2 of U.S. Pat. No. 4,837,422) and on which there is 
stored a third code (a SUBPIN code stored in memory 207 in FIG. 2 of U.S. 
Pat. No. 4,837,422). Generally, said PIN code and SUBPIN code are stored 
in encrypted manner. 
In the event of a first authentication process relating to, e.g., a first 
system and, e.g., a first user, the same generates the real PIN code (the 
second code), which is received by the first system, whereafter the PIN 
code stored in encrypted manner (the first code) is read out and (by way 
of the first transformation) is decrypted, which provides the PIN code 
(the transformed first code). The same is then compared to the generated 
real PIN code (the second code), and in response thereto the first 
authentication process is rounded off positively (in the event of 
equality) or negatively (in the event of unequality). Instead of or in 
addition to, as the case may be, the decryption of the encrypted PIN code 
(transforming, by way of the first transformation, the first code into the 
transformed first code), one of the options also is to transform the real 
PIN code generated by the first user (the second code) by way of the 
second transformation into the transformed second code, whereafter on the 
one hand said transformed second code is compared to on the other hand the 
first code or the transformed first code, as the case may be, etc. 
In the event of a second authentication process relating to, e.g., a second 
system and, e.g., a second user, the same generates the real SUBPIN code 
(the fourth code), which is received by the second system, whereafter the 
SUBPIN code stored in encrypted manner (the third code) is read out and 
(by way of the third transformation) is decrypted, which provides the 
SUBPIN code (the transformed third code). The same is then compared to the 
generated real SUBPIN code (the fourth code), and in response thereto the 
second authentication process is rounded off positively (in the event of 
equality) or negatively (in the event of unequality). Instead of or in 
addition to, as the case may be, the decryption of the encrypted SUBPIN 
code (transforming, by way of the third transformation, the third code 
into the transformed third code), one of the options also is to transform 
the real SUBPIN code generated by the second user (the fourth code) by way 
of the fourth transformation into the transformed fourth code, whereafter 
on the one hand said transformed fourth code is compared to on the other 
hand the third code or the transformed third code, as the case may be, 
etc. 
Both authentication processes might further relate to various systems 
having one user, or might relate (as in U.S. Pat. No. 4,837,422) to one 
system having various users. 
Such a method has the drawback, inter alia, that for the benefit of the 
first authentication process, the first code should be on the data carrier 
and that for the benefit of the second authentication process, the third 
code should be on the same data carrier. As a result, it becomes 
impossible to make use of data carriers already frequently in circulation, 
which do not dispose of the option of storing a next code for each next 
authentication process. 
SUMMARY OF THE INVENTION 
One of the objects of the invention is to provide a method of the kind 
referred to in the preamble, it becoming possible to make use of data 
carriers already frequently in circulation, which do not dispose of the 
option of storing a next code for each next authentication process. 
For this purpose, the method according to the invention is characterised in 
that the first code and the third code are equal, whereas the second code 
and the fourth code are different, and with at least one of the respective 
first and second transformations differing from the respective third and 
fourth transformations. 
Since at least one of the respective first and second transformations 
differs from the respective third and fourth transformations, the first 
code and the third code may be equal and coincide completely while the 
second code and the fourth code are still different. Here, the option 
arises of using data carriers where only the first code (which is equal 
to, and coincides with, the third code) has been stored, while said data 
carriers still can be used for the benefit of, e.g., two different 
authentication processes, which then require generation of the second code 
and the fourth code, respectively. 
The invention is founded, inter alia, on the insight that the first 
authentication process is based on at least three parameters, namely the 
first code, the second code and at least one (first or second) 
transformation, and the second authentication process is based on at least 
three parameters, namely the third code, the fourth code and at least one 
(third or fourth) transformation, and that, when of at least three 
parameters one parameter receives a fixed value, the other at least two 
parameters may still be chosen freely. 
Thus, the problem of the inability to make use of data carriers already 
frequently in circulation, which do not dispose of the option to store a 
next code for each next authentication process, is solved by in at least 
one system adjusting at least one transformation. 
A first embodiment of the method according to the invention is 
characterised in that the first transformation differs from the third 
transformation, with the second transformation being equal to the fourth 
transformation. 
Here, in the event of the first authentication process relating to the 
first system and the first user, there is generated, by said first user, 
the second code, which is received by the first system, whereafter the 
first code stored in encrypted manner or the third code stored in 
encrypted manner is read out and decrypted by way of the first 
transformation, which provides the first code transformed in a first 
manner or the third code transformed in a first manner, which is then 
compared to the second code generated (and possibly transformed in a 
second manner), and in response thereto the first authentication process 
is rounded off positively (in the event of equality) or negatively (in the 
event of unequality). In the event of the second authentication process 
relating to the second system and the second user, there is generated, by 
said second user, the fourth code, which is received by the second system, 
whereafter the first code stored in encrypted manner or the third code 
stored in encrypted manner is read out and is decrypted by way of the 
third transformation, which provides the first code transformed in a third 
manner or the third code transformed in a third manner, which is then 
compared to the fourth code generated (and possibly transformed in a 
fourth manner), and in response thereto the second authentication process 
is rounded off positively (in the event of equality) or negatively (in the 
event of unequality). Since the first transformation and the third 
transformation differ, there therefore has to be generated, for each 
system, another code (the second or the fourth) by the user, while there 
is located on the data carrier still only one code (the first or the 
third). The second transformation and the fourth transformation are 
mutually equal, and might in the most simple case be left out, which will 
not promote safety in general, however. 
A second embodiment of the method according to the invention is 
characterised in that the second transformation differs from the fourth 
transformation, with the first transformation being equal to the third 
transformation. 
Here, in the event of the first authentication process relating to the 
first system and the first user, there is generated, by said first user, 
the second code, which is received by the first system and is transformed 
into the second code transformed in a second manner, whereafter the first 
code (possibly stored in encrypted manner) or the third code (possibly 
stored in encrypted manner) is read out and is possibly decrypted by way 
of the first transformation, which provides the first code (possibly 
transformed in a first manner) or the third code (possibly transformed in 
a first manner), which is then compared to the second code generated and 
transformed in a second manner, and in response thereto the first 
authentication process is rounded off positively (in the event of 
equality) or negatively (in the event of unequality). In the event of the 
second authentication process relating to the second system and the second 
user, there is generated, by said second user, the fourth code, which is 
received by the second system and is transformed into the fourth code 
transformed in a fourth manner, whereafter the first code (possibly stored 
in encrypted manner) or the third code (possibly stored in encrypted 
manner) is read out and is possibly decrypted by way of the third 
transformation, which provides the first code (possibly transformed in a 
third manner) or the third code (possibly transformed in a third manner), 
which is then compared to the fourth code generated and transformed in a 
fourth manner, and in response thereto the second authentication process 
is rounded off positively (in the event of equality) or negatively (in the 
event of unequality). Since the second transformation and the fourth 
transformation differ, there therefore has to be generated, for each 
system, another code (the second or the fourth) by the user, while there 
is located on the data carrier still only one code (the first or the 
third). The first transformation and the third transformation are mutually 
equal, and might in the most simple case be left out, which will not 
promote safety in general, however. 
A third embodiment of the method according to the invention is 
characterised in that the first transformation differs from the third 
transformation, and the second transformation differs from the fourth 
transformation. 
Here, in the event of the first authentication process relating to the 
first system and the first user, there is generated, by said first user, 
the second code, which is received by the first system and is transformed 
into the second code transformed in a second manner, whereafter the first 
code stored in encrypted manner or the third code stored in encrypted 
manner is read out and is decrypted by way of the first transformation, 
which provides the first code transformed in a first manner or the third 
code transformed in a first manner, which is then compared to the second 
code generated and transformed in a second manner, and in response thereto 
the first authentication process is rounded off positively (in the event 
of equality) or negatively (in the event of unequality). In the event of 
the second authentication process relating to the second system and the 
second user, there is generated, by said second user, the fourth code, 
which is received by the second system and is transformed into the fourth 
code transformed in a fourth manner, whereafter the first code stored in 
encrypted manner or the third code stored in encrypted manner is read out 
and is decrypted by way of the third transformation, which provides the 
first code transformed in a third manner or the third code transformed in 
a third manner, which is then compared to the fourth code generated and 
transformed in a fourth manner, and in response thereto the second 
authentication process is rounded off positively (in the event of 
equality) or negatively (in the event of unequality). Since not only the 
first transformation and the third transformation differ, but also the 
second transformation and the fourth transformation differ, there 
therefore has to be generated, for each system, another code (the second 
or the fourth) by the user, while there is located on the data carrier 
still only one code (the first or the third), it being possible to speak 
of a well-protected system. 
A fourth embodiment of the method according to the invention is 
characterised in that at least one of the transformations depends on a 
fifth code stored on the data carrier. 
Since at least one of the transformations depends on a fifth code stored on 
the data carrier, such as, e.g., a number of a (giro or bank) account or a 
birth date, it becomes considerably more difficult to fathom the method 
according to the invention, which benefits safety. 
The invention further relates to a system for being capable of carrying 
out, with the same data carrier, various authentication processes, on 
which data carrier there is stored at least one code, which system in the 
event of a first authentication process is provided with 
first receiving means for receiving a first code stored on the data carrier 
and a second code originating from a user, 
first transforming means for carrying out at least one of the following 
transformations 
a first transformation of the first code into a transformed first code, and 
a second transformation of the second code into a transformed second code, 
first comparing means for comparing codes for in response thereto rounding 
off the first authentication process, and which system in the event of a 
second authentication process is provided with 
second receiving means for receiving a third code stored on the data 
carrier and a fourth code originating from a user, 
second transforming means for carrying out at least one of the following 
transformations 
a third transformation of the third code into a transformed third code, and 
a fourth transformation of the fourth code into a transformed fourth code, 
second comparing means for comparing codes for in response thereto rounding 
off the second authentication process. 
The system according to the invention is characterised in that the first 
code and the third code are equal, whereas the second code and the fourth 
code are different, and with at least one of the respective first and 
second transformations differing from the respective third and fourth 
transformations. 
A first embodiment of the system according to the invention is 
characterised in that the first transformation differs from the third 
transformation, with the second transformation being equal to the fourth 
transformation. 
A second embodiment of the system according to the invention is 
characterised in that the second transformation differs from the fourth 
transformation, with the first transformation being equal to the third 
transformation. 
A third embodiment of the system according to the invention is 
characterised in that the first transformation differs from the third 
transformation, and the second transformation differs from the fourth 
transformation. 
A fourth embodiment of the system according to the invention is 
characterised in that at least one of the transformations depends on a 
fifth code stored on the data carrier. 
REFERENCES 
U.S. Pat. No. 4,837,422 
"Contemporary Cryptology", The Science of Information Integrity, edited by 
Gustavus J. Simmons, IEEE Press, 1992 
"Cryptography: a new dimension in computer data security", A guide for the 
Design and Implementation of Secure Systems, by Carl H. Meyer and Stephen 
M. Matyas, A Wiley-Interscience Publication, John Wiley & Sons, 1982 
NL 1000988 Dutch patent application 
All references are considered incorporated in the present patent 
application.

The system shown in FIG. 1 according to the invention comprises first 
receiving means 1 which are provided, e.g., with a keyboard device 2 and a 
card reader 3, and comprises first transforming means 4 coupled to the 
first receiving means 1 which are provided with, e.g., an enciphering 
device 5, processor means 6 and an enciphering device 7. A first input of 
enciphering device 5 is coupled, by way of a connection 9, to an output of 
keyboard device 2, and a first input of enciphering device 7 and an input 
of processor means 6 are coupled, by way of a connection 10, to an output 
of card reader 3. A first output of processor means 6 is coupled, by way 
of a connection 11, to a second input of enciphering device 5, and a 
second output of processor means 6 is coupled, by way of a connection 12, 
to a second input of enciphering device 7. An output of enciphering device 
5 is coupled, by way of a connection 13, to a first input of a first 
comparing device 8, and an output of enciphering device 7 is coupled, by 
way of a connection 14, to a second input of first comparing device 8, 
which is further provided with an output 15. 
The system shown in FIG. 1 according to the invention further comprises 
second receiving means 21 which are provided, e.g., with a keyboard device 
22 and a card reader 23, and the system comprises second transforming 
means 24 coupled to the second receiving means 21 which are provided, 
e.g., with an enciphering device 25, processor means 26 and an enciphering 
device 27. A first input of enciphering device 25 is coupled, by way of a 
connection 29, to an output of keyboard device 22, and a first input of 
enciphering device 27 and an input of processor means 26 are coupled, by 
way of a connection 30, to an output of card reader 23. A first output of 
processor means 26 is coupled, by way of a connection 31, to a second 
input of enciphering device 25, and a second output of processor means 26 
is coupled, by way of a connection 32, to a second input of enciphering 
device 27. An output of enciphering device 25 is coupled, by way of a 
connection 33, to a first input of a second comparing device 28, and an 
output of enciphering device 27 is coupled, by way of connection 34, to a 
second input of second comparing device 28, which is further provided with 
an output 35. 
The operation of the system shown in FIG. 1 is as follows. A first user, 
who at a given moment has in his possession a data carrier such as, e.g., 
a magnetic card, on which there is stored a first code 40, places said 
magnetic card in card reader 3, which reads out the first code 40 and 
further data (such as account number and name and address), whereafter the 
first code 40 is fed, by way of connection 10, to enciphering device 7 and 
the further data is fed, by way of connection 10, to processor means 6. 
Furthermore, said first user by way of keyboard 2 generates a second code 
which is fed, by way of connection 9, to enciphering device 5. In response 
to the further data, processor means 6 generate a first key which is fed, 
by way of connection 12, to enciphering device 7 which, in response to 
said first key, transforms the first code into a transformed first code 
and transmits the same, by way of connection 14, to first comparing device 
8. In response to the further data, processor means 6 further generate a 
second key which is fed, by way of connection 11, to enciphering device 5 
which, in response to said second key, transforms the second code into a 
transformed second code, and transmits the same, by way of connection 13, 
to first comparing device 8 which compares both transformed codes with one 
another and, in the event of equality, generates a positive authentication 
signal by way of output 15 and, in the event of unequality, generates a 
negative authentication signal by way of output 15. In response to the 
positive authentication signal, the first user gains access, e.g., to an 
automatic cash dispenser. 
A second user who at a given moment has in his possession the same data 
carrier such as, e.g., the magnetic card, on which there is stored the 
first code 40, places said magnetic card in card reader 23, which reads 
out the first code 40 and further data (such as account number and name 
and address), whereafter the first code 40 is fed, by way of connection 
30, to enciphering device 27 and the further data is fed, by way of 
connection 30, to processor means 26. Furthermore, said second user 
generates, by way of keyboard 22, a fourth code which is fed, by way of 
connection 29, to enciphering device 25. In response to the further data, 
processor means 26 generate a third key which is fed, by way of connection 
32, to enciphering device 27 which, in response to said third key, 
transforms the first code into a transformed first code and transmits the 
same, by way of connection 34, to second comparing device 28. In response 
to the further data, processor means 26 further generate a fourth key 
which is fed, by way of connection 31, to enciphering device 25 which, in 
response to said fourth key, transforms the fourth code into a transformed 
fourth code and transmits the same, by way of connection 33, to second 
comparing device 28 which compares both transformed codes with one another 
and, in the event of equality, generates a positive authentication signal 
by way of output 35 and, in the event of unequality, generates a negative 
authentication signal by way of output 35. In response to the positive 
authentication signal, the second user gains access, e.g., to an automatic 
parcel device, with the postal expenses of a parcel to be mailed being 
determined and charged in an automatic manner. 
Since the second user is not familiar with the second code, he will not 
succeed in gaining access to the automatic cash dispenser. In general the 
first user, if he is, e.g., the owner of the data carrier, or is the boss 
of a company which possesses the data carrier and which employs the second 
user, will be familiar with both the second and the fourth code, though 
such is not required. Thus, by way of the same data carrier on which there 
are stored the first code and some further data, various authentication 
processes may be carried out, with at least one of the users, due to 
unfamiliarity with at least one of the codes, not being capable of 
rounding off at least one of the authentication processes with positive 
result. 
The first code stored on the data carrier therefore is a (possibly 
encrypted) PIN code (Personal Identification Number), and since either at 
least the first code by way of the first key and the first code by way of 
the third key are transformed in a different manner, or at least the 
second code by way of the second key and the fourth code by way of the 
fourth key are transformed in a different manner, it is achieved that it 
is no longer required to store various PIN codes (such as a PIN code and a 
SUBPIN code, or a first code and a third code) on the same data carrier. 
As a result, use may be made of worldwide distributed standard data 
carriers (such as, e.g., magnetic cards or chip cards), which of course is 
of great advantage. 
If both the first code by way of the first key and the first code by way of 
the third key are transformed in a different manner, and additionally the 
second code by way of the second key and the fourth code by way of the 
fourth key are transformed in a different manner, safety will generally be 
best. By rendering at least one of said transformations dependent upon a 
fifth code stored on the data carrier (such as at least a portion of the 
further data), said safety is still further enhanced. In this case 
processor means 6, in response to a first portion of the further data 
(e.g., the account number), might generate a first value and a second 
value from a table, whereafter the first value, in response to a second 
portion of the further data (e.g., the name), is used to calculate the 
first key, and the second value, in response to a third portion of the 
further data (e.g., the address), is used to calculate the second key. 
Furthermore processor means 26, in response to a first portion of the 
further data (e.g., the account number), might generate a third value and 
a fourth value from a table, wherafter the third value, in response to a 
second portion of the further data (e.g., the name), is used to calculate 
the third key, and the fourth value, in response to a third portion of the 
further data (e.g., the address), is used to calculate the fourth key. 
Also, at least one of the transformations may be rendered dependent upon, 
e.g., the fifth code by combining said fifth code, in a manner known to 
those skilled in the art, with the code arriving by way of at least one of 
the connections 9, 10, 29 and 30. 
Processor means 6 (26) comprise, e.g., a detector for detecting the further 
data, a table memory having at least three columns, with a first column 
serving to store, e.g., account numbers, and a second column serving to 
store a first (third) key or a first (third) value, and a third column 
serving to store a second (fourth) key or a second (fourth) value, and 
comprise a processor for controlling the detector and the table memory, 
and for possibly calculating the first and second (third and fourth) keys, 
respectively, on the basis of the first and second (third and fourth) 
values, respectively and, e.g., names and addresses. Enciphering devices 5 
and 6 (25 and 26) are, e.g., encryption circuits known to those skilled in 
the art which, e.g., convert an x-bit input word as a function of a y-bit 
key word into a z-bit output word, with the relationship x=y=z generally 
applying, though not absolutely necessary. Comparing device 8 (28) is, 
e.g., a comparator known to those skilled in the art. 
First transforming means 4 therefore carry out, by way of enciphering 
device 7, a first transformation of the first code into a transformed 
first code by way of the first key, and therefore carry out, by way of 
enciphering device 5, a second transformation of the second code into a 
transformed second code by way of the second key. Second transforming 
means 24 therefore carry out, by way of enciphering device 27, a third 
transformation of the first (=third) code into a transformed first 
(=transformed third) code by way of the third key, and therefore carry 
out, by way of enciphering device 25, a fourth transformation of the 
fourth code into a transformed fourth code by way of the fourth key. Of 
course, many other transformations known to those skilled in the art may 
be applied, such as, e.g., transformations not based on keys.