 |
Description  |
|
|
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method and an apparatus for forming
identification data for demonstrating authenticity of the user of a
peripheral device in making data communications with other peripheral
devices or computer centers in the data communication network including a
plurality of peripheral devices for data communication and computer
centers.
2. Description of the Prior Art
In a data communication network including a plurality of peripheral device
for data communication and a computer center or centers in general, it is
necessary to check that the user is authorized to use the network and to
cipher the data transmitted through the communication network, in order to
enable only the authorized user to have access to the host machine to
assure data security such as data confidentiality.
Heretofore, in checking that the user is an authorized user, identification
data allocated to each user and the password optionally designated by the
user are registered at a host machine. The user transmits the
identification data and the password from the terminal machine to the host
machine and the identification data and the password received at the host
machine are compared with the identification data and the password
registered at the host machine.
For example, in a cash dispenser making use of an on-line system of banking
facilities, an ID card such as a magnetic card or an IC card with
prerecorded identification data of a user is utilized to demonstrate that
the user is an authorized user of a bank account. The method of
identifying a person by an IC card is shown for example in the Japanese
Laid-open Patent Publication No. 146361/1985.
On the other hand, data transmitted through a communication network are
protected by ciphering the data on the communication network by a
ciphering device of the DES or RSA system provided on the communication
network.
It is noted that, in the data communication network in general, the
password optionally designated by the user is apt to be decoded and, once
the ID card is forged or stolen, it becomes impossible to identify the
authorized user, so that the chance that the host machine is illegally
accessed is increased. On the other hand, the identification data
allocated to the user are formed by a dedicated data processing device at
the time of the preparation of the ID card or at a host machine of the
data communication network. There is the risk of theft of the data
processing device, the identification data formation algorithm at the host
machine or of the identification data per se. Thus a demand has been
raised for evolving the method and the apparatus for forming the
identification data of high data security or confidentiality.
OBJECT AND SUMMARY OF THE INVENTION
It is a principal object of the present invention to provide a method and
an apparatus for forming identification data of improved data security.
It is another object of the present invention to prevent unauthorized
accessing of the host machine in the data communication network and to
realize highly reliable data security functions.
It is a further object of the present invention to provide a method and an
apparatus for forming identification data of higher data security that may
be implemented with a simpler design and at lower costs.
In accordance with the present invention, there is provided a method for
forming identification data comprising reading out data of a prescribed
number of bits from random number data on the basis of key data, the
random number data being formed of a large number of bits and previously
stored in a memory; forming new key data at least a part of which is
formed by the data of a prescribed number of bits read out from the random
number data, reading out data of a prescribed number of bits from the
random number data on the basis of the new key data; the read-out
operation being repeatedly performed; and forming identification data from
the data of the prescribed number of bits repeatedly read out from the
random number data formed of a large number of bits.
In accordance with the present invention there is also provided memory in
which random number data of a large, number of bits are previously stored;
address forming unit for forming addresses for reading out data of a
prescribed number of bits from the memory on the basis of key data; and a
data read-out unit for transmitting data of a prescribed number of bits
read out from the memory to the address forming unit for at least a part
of new key data; the identification data being formed from data each
consisting of a prescribed number of bits read out from the memory to said
address forming large number of bits.
In the method and the apparatus for forming identification data in
accordance with the present invention, data of a predetermined number of
bits read out on the basis of key data from data of a large number of bits
previously stored in a terminal machine in a data communication network
are used for at least a portion of new key data and the data each being of
a predetermined number of bits are repeatedly read out from the
aforementioned random number data of a large number of bits for forming
identification data. In such manner, there are obtained identification
data of extremely high data security that are unequivocally defined with
respect to the key data by the algorithm of forming the identification
data at the terminal machine and the algorithm of forming the key data at
the host machine. On the other hand, when the identification data formed
at the terminal machine from the random number data on the basis of the
key data are registered at the host machine, it may be checked at the host
machine that the user is an authorized user by simply having the key data
proper to each terminal machine controlled or managed at the host machine.
In addition, when the identification data formed from the random number
data at the terminal machine on the basis of the received key data are
combined into transmitted data at the host machine, the transmitted data
itself is protected, so that, in case of leakage of the transmitted data,
an authorized user may optionally duplicate the received data without the
contents of the transmitted data being known by third parties.
BRIEF DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing a first embodiment of the present
invention as applied to the data communication network;
FIG. 2 is a flow chart showing the essential operation of the first
embodiment; and
FIG. 3 is a block diagram showing a second embodiment of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A preferred embodiment of a data communication network making use of the
method and the apparatus for forming identification data according to the
present invention will be hereafter described by referring to the
accompanying drawings.
In FIG. 1, there is illustrated in a block view a first embodiment
according to the present invention. In the first embodiment shown in FIG.
1, a host machine 10 of the data communication network is formed by a
general network control unit (NCU) 11, a modulation/demodulation unit
(MODEM) 12, a ciphering/deciphering circuit 13 and a system controller 14
necessary for supplying and receiving data to or from a plurality of
terminal machines 30, a data memory 15 for storing data required by users
of the data communication. network and a registered data memory 16
necessary for storing registered data necessary for identifying the
terminal machine 30.
Each terminal machine 30 is formed by a communication adapter 37 comprised
of a network control unit (NCU) 31, a modulation/demodulation unit (MODEM)
32, a ciphering/deciphering circuit 33 corresponding to those of the host
machine 10, an arithmetic operating and processing unit 34 for formation
of identification data, a random number data memory 35 consisting of a
read-only memory (ROM) with previously written random number data of, for
example, 32 K bytes, similarly for forming identification data and a
system controller, 36 controlling the arithmetic operating and processing
unit including the random number data memory. The remote terminal 30 also
includes a data terminal 40 comprised of a data memory 38 for storage of
data
transmitted from the host machine 10, a keyboard 39a for inputting
operating data, and a display 39b.
In the present first embodiment, the arithmetic operating and processing
unit 34 for formation of the identification data is formed by a first
register 41 for transient storage of key data (KD), a first irreversible
function or Fa processing unit 42 for subjecting the key data (KD) stored
in the register 41 to irreversible function processing, reading the thus
processed data and forming address data, AD, a second register 43 for
transient storage of read-out address data AD formed in the Fa processing
unit 42, a third register 44 for transiently storing data RD read out from
a storage location of the random number memory 35 designated by the
address data AD stored in the register 43, a second irreversible function
or Fb processing unit 45 for subjecting the data RD stored in the register
44 to irreversible function processing, a fourth register 46 for
transiently storing data id formed in the irreversible function or Fb
processing unit 45 and a transmission buffer 47 for transiently storing
identification data or ID data formed in the operating and processing unit
34. It is noted herein that semiconductor RAMs may be used as the register
41, 43, 44 or 46 or as the transmission buffer 47, while so-called
programmable array logics or PALs may be used as the irreversible function
processing unit 42, 45 and a semiconductor ROM may be used as the random
number memory 35.
In the data communication network of the present embodiment, when making
user registration for utilizing a data base, an ID number ID.sub.0
allocated to each terminal machine 30 at the host machine 10, a password
PW arbitrarily designated by the user and a key data KD.sub.1 randomly
produced for each ID number by the host machine 10, are registered in a
registered data memory 16 of the host machine 10. As the user inputs his
ID number ID.sub.0 and his password PW in the terminal machine 30 and
accesses the host machine 10, the identification data ID.sub.1 may be
registered in the registered data memory 16 in the following manner.
That is, in registering the identification data ID.sub.1, the user operates
the terminal machine 30 to transmit the ID number ID.sub.0 and the
password PW to access the host machine 10. The host machine 10
acknowledges that the received ID number ID.sub.0 and password PW coincide
with the ID number ID.sub.0 and password PW registered in the registered
data memory 16 and transmits the key data KD.sub.1 allocated to each
terminal machine 30 in association with the ID number ID.sub.0 to the
terminal machine 30. The terminal machine 30 fetches the received key data
KD.sub.1 to the operating and processing unit 34 to form identification
data ID.sub.1 of a predetermined length on the basis of the key data
KD.sub.1 which identification data ID.sub.1 is retransmitted to the host
machine 10. The host machine 10 registers the received identification data
ID.sub.1 in the registered data memory 16.
The arithmetic operating and processing unit 34 of the terminal machine 30
forms and transmits the identification data ID.sub.1 in the following
manner.
On receiving the aforementioned key data KD.sub.1 the arithmetic operating
and processing unit 34 fetches the key data KD.sub.1 of, for example, 16
bits, to the first register 41, forms read-out address data AD in the Fa
processing unit 42 using the key data KD.sub.1 as the parameter and writes
the read-out address data AD in the second register 43. The unit 34 then
reads out a 1-byte data RD from, for example, 32K-byte random number data
previously written in the random number data memory 35 at a storage
location thereof designated by the aforementioned read-out address data
AD, and writes the read-out 1-byte data, for example, in the third
register 44. The unit 34 then forms a 1-byte identification data id in the
Fb processing unit 45 using the data RD written in the register 44 as the
parameter and writes the formed identification data id in the fourth
register 46. The aforementioned identification data id are transmitted
from the fourth register 46 to the transmission buffer 47 where they are
stored. The unit 34 then moves the lower 8 bits of the key data KD.sub.1
stored in the first register 41 to the position of the upper 8 bit
position while moving the aforementioned 1-byte data RD stored in the
third register 44 to the first register 41 as the lower 8 bit data to form
new key data KD. In the present embodiment, the aforementioned arithmetic
operation and processing is repeated 128 times, for example, using newly
formed key data KD each time to form the 128-byte identification data
ID.sub.1 in the transmission buffer 47, which data are transmitted from
the transmission buffer 47 to the host machine 1 0 through the
ciphering/deciphering circuit 33, MODEM 32 and NCU 31. The length L of the
identification data ID, (in the present embodiment, it is equivalent to
the number of times of repetition of the arithmetic operation) is not
limited to 128 as described above and may be set optionally.
Alternatively, the numerical data of the length L of the identification
data or the data of the number of times of the repetitive operation in the
present embodiment may be transmitted to the terminal machine 30 so that
the length of the identification data ID.sub.1 will be determined in the
host machine.
An exemplary operation of forming identification data ID.sub.1 at the
terminal machine 30 will be described by referring to the flow chart of
FIG. 2. In this figure, it is assumed that the length L of the
identification data and the key data KD.sub.1 are transmitted to the
terminal machine 30, and that the key data KD.sub.1 is formed by 2 bytes
or 16 bits, with the upper and lower 8 bits being indicated by K.sub.H and
K.sub.L respectively.
At the first step S.sub.1 of FIG. 2, the length L of the identification
data transmitted from the host machine 10 and the key data KD.sub.1 (with
the upper 8 bits of K.sub.H and the lower 8 bits of K.sub.L ) are
received. At the next step S2, the loop control variable W is set to 0 and
the aforementioned data (K.sub.H K.sub.L) are stored as the usual key data
KD in the register 41. At the next step S3, it is determined whether the
aforementioned loop control variable W is less than L. If affirmative,
control proceeds to the next step S4, the key data KD in the register 41
are transmitted to the Fa processing unit where they are processed to
produce read-out address data AD which are written in the register 43. At
the next step S5, the 1-byte data x of the 32K byte random number data
previously written in the random number data memory 35 are read out at a
memory location designated by the read-out address data AD. At the next
step S6, the data x are written as the aforementioned data RD in the
register 44. At the next step S7, the lower 8 bits K.sub.L of the key data
KD stored in the register 41 are moved to the position of the upper 8 bits
K.sub.H. At the step S8, the aforementioned 1-byte data RD stored in the
register 44 are moved to the register 41 as the lower 8-bit K.sub.L data
to form new key data KD. At the next step S9, the data RD written in the
register 44 are transmitted to the Fb processing unit 45 where they are
processed to produce one-byte data id of the L-byte identification data,
which data id is written into the register 46. At the next step S10, the
one-byte data id is written into the W th byte in the storage area of the
L-byte identification data ID provided in the transmission buffer 47. At
the next step S11, the loop control variable W is incremented (W=W+1),
after which control is resumed to step S3. After the aforementioned
operational sequence is repeated L times and if then the result of
decision at the step S3 is NO, control proceeds to step S12, where the
L-byte identification data ID stored in the transmission buffer 47 are
transmitted to the host machine 10. It is noted herein that the
identification data associated with the aforementioned key data KD.sub.1
are indicated as ID.sub.1.
In this manner, the aforementioned identification data ID.sub.1
retransmitted from the terminal machine 30 are registered at the
registered data memory 16 of the host machine 10, in association with the
key data KD.sub.1 allotted to the terminal machine 30. Then, each time the
host machine is accessed by the terminal machine 30 by the ID number
ID.sub.0 and the password PW, the host machine 10 acknowledges the
coincidence between these ID numbers. The host machine 10 then transmits
the key data KD.sub.1 and acknowledges the coincidence between the
identification data ID.sub.1 returned from the terminal machine 30 and the
identification data ID.sub.1 stored in the registered data memory 16 to
confirm that the user is an authorized user.
Should the key data KD.sub.1 registered at the host machine 10 be leaked to
an unauthorized third party, the host machine 10 may alter the key data
KD.sub.1 and generate identification data ID.sub.1 associated with new key
data KD.sub.1 by using the aforementioned algorithm of generating initial
identification data for re-registration of the new identification data.
In the present embodiment, when the information required by the user is
read out from the data memory 15 and transmitted from the host machine 10
to the terminal machine 30, the host machine 10 first generates disposable
or nonce key data KD.sub.2 and transmits these data to the terminal
machine 30 each time the information is transmitted. The host machine 10
then causes the arithmetic operating and processing unit 34 to form new
n-byte identification data ID.sub.2 from the random number data by using
the same artifice as that used for forming the identification data
ID.sub.1 and then causes these data ID.sub.2 to be retransmitted to the
machine 10. The host machine 10 then reads out the information requested
by the user from the data memory 15, incorporates the received
identification data ID.sub.2 and the aforementioned key data KD2 into the
information read-out from the data memory 15 and transmits the resulting
combined data to the terminal machine 30.
The terminal machine 30 writes the received data, that is, the information
into which are combined the identification data ID.sub.2 and the key data
KD.sub.2 into the data memory 38. When the user uses the information
written into the data memory 38, the key data KD.sub.2 combined into the
information is transmitted to the arithmetic operating and processing unit
34, while the identification data ID.sub.2 generated by the aforementioned
algorithm of forming the identification data are re-transmitted to a data
terminal 40. The data terminal 40 proceeds to compare the identification
data ID.sub.2 combined into the information with the re-transmitted data
ID.sub.2. Unless these data are coincident with each other, the key lock
remains engaged to inhibit the use of the received data. In other words,
any one other than the one authorized to use the terminal machine 30
having received the data cannot use the received data.
It is noted that, by using floppy disks as the data memory 38, the
authorized user may optionally produce a duplicate disk as a backup of the
disk on which are recorded the received data. However, the information
cannot be used by any one other than the authorized user.
In the data communication network of the present embodiment, the data
composed of a predetermined number of bits repeatedly read out from random
number data composed of a number of a number of bits previously stored in
a terminal machine on the basis of key data are used as new key data,
thereby forming identification data of extremely high security
unequivocally determined in accordance with different key data afforded by
the host machine to the respective terminals, these identification data
being user-registered at the host machine. Thus it is only necessary to
control or manage the key data proper to the respective terminals to
identify the authorized user securely and positively. Should key data be
leaked to an unauthorized third party, it is only necessary to alter the
key data of the host machine in order to provide for information security
without the necessity of changing the hardware of the terminal machine.
When there are a plurality of host machines, it is only necessary to
separately control or manage the key data to be afforded to the terminal
machines registered as the users at the host machines in order to identify
the users reliably by using the same hardware. When the same communication
adapter is used by plural users, it is only necessary for the host machine
to control or manage key data and identification data. In addition, since
the identification data formed at the terminal machines on the basis of
the key data are combined at the host machine into the data to be
transmitted from the host machine, the received data per se are protected
in such a manner that only the terminal machines having the aforementioned
identification data formation algorithm can utilize the contents of the
received data. Thus, in case of leakage of the received data, the received
data can be optionally duplicated by the authorized user without the
contents thereof being known by third parties, so that there may be
realized a data communication network that is most suitable for on-line
delivery of the software by making use of the communication network.
The present invention is not limited to the above described embodiments.
For example, instead of the 1-byte data RD from the third register 44, the
1-byte data id from the fourth register 46 may be transmitted to the first
register 41 as the data of the lower 8 bits K.sub.L of the new key data,
as in the second embodiment shown in FIG. 3. The arrangement and the
operation of the second embodiment are otherwise the same as that of the
above described first embodiment so that parts or components of FIG. 3
corresponding to those of FIG. 1 are indicated by the same numerals and
the corresponding description is omitted. It is to be noted that various
changes can also be made without departing from the scope of the
invention. For example, the number of times of repetition of the
aforementioned arithmetic operation and processing may be different from
the length L of the key data KD.
* * * * *
|
|
 |
|
 |
Description |
|
