Note: Descriptions are shown in the official language in which they were submitted.
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WO 96/00485 PCT/SE95/00719
1
USER AUTHENTICATION METHOD AND APPARATQS
B_ACKG~,OTJND OF THE INVENTI~JN
1) ~,ield of the Invention
The present invention involves a method and an apparatus
for authentication of a user attempting to access an electro
nic service, and, in particular, providing an authentication
unit Which is separate from preexisting systems.
2) Description of elated Art
Effective authentication methods and apparatuses have
been in great demand to prevent fraud and theft of services.
This demand increases with the explosion of electronic
services in the current information age. E:Lectronic services
such as banking services, credit card services, automatic
teller machine (ATM) services, account information services
such as mortgage, savings and investment accounts, general
information services such as data base services and networks,
security services and long distance phone services all require
that a user be accurately identified for purposes of security,
proper billing and avoidance of fraud. Recently, fraud in the
cellular mobile telephone industry has placed so great a
demand on effective authentication methods that a protocol has
been standardized for cellular mobile systems. See, GSM
03.20, European Telecommunications Standards Institute
(ETSI) , 1993, pp. 19-29 and U.S. Patent No. 5,282,250, herein
incorporated by reference.
However, conventional authentication systems have
required specially equipped terminals with card readers such
as ATMs or credit card gas station terminals, data terminals
using a log-in procedure, or cellular mobile radio stations
with built-in authentication capabilities. Credit cards
having a magnetic strip provide only minimal security insomuch
as the bearer of the card is usually pezzaitted to conduct
transactions without further authentication of the user's
identification other than perhaps comparing a unauthenticated
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WO 96/00485 ' PCTISE95100719
2
signature on the card to a signature of the user. Even in
transactions when signatures are required, the certainty of
the user's identification is minimal.
Other identity cards, such as ATM cards, require a log-on
procedure with a password, or PIN. But the PIN, once learned
by an unauthorized user, offers no security in authenticating
the user if the user can duplicate the ATM card.
These methods of authentication require specially
equipped, and often dedicated, terminals,, which raises the
l0 cost and reduces the availability of the associated electronic
service. In other words, the prior art security systems often
require a dedicated or customized terminal or modification to
existing terminals, which greatly restricts the use of
security systems to specific sites. Also, a user may use
several electronic services, each service requiring an
authentication procedure and/or personal identification
number (PIN) or password, each procedure or password different
from the others. As a subscriber to several electronic
services, a user might end up with numerous passwords to
remember. Even worse, he or she may be required to change
these passwords periodically, thus having to remember if a
password is still valid or not.
Also, transactions requiring relatively certain authen
tication have been largely unavailablefrom relatively simple
terminals like telephones. For instance, home banking by
telephone has been limited to transactions involving the bank
customer's own accounts or using only the customer's own
telephone.
SUMMARY OF THE INVENTION
The present invention overcomes these and other problems
by providing an authentication procedure wherein the user
carries a personal unit not limited to use pith or physically
connected to a terminal of any one specific electronic
service. The personal unit ca~a be used to authenticate a
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user's identity through a variety of terminals associated with a variety of
electronic
services.
The personal unit includes a receiver for receiving a transmitted challenge
code
and an algorithm unit which processes the challenge code, a user input such as
a personal
identification number (PIN) or electronically recognizable signature, and an
internally
stored security key for calculating a response code according to a pre-stored
algorithm.
The response code is then sent to the service node and, if it is acceptable,
access to the
service is authorized.
The basic method involves receiving a challenge code from a system, the user
inputting a personal identification number or other recognizable input, and
the personal'
unit generating a response code based on an internally storedL algorithm. The
PIN or
other user input may be changed from time to time, and the challenge code and
the
response is unique for each transaction. The personal unit may receive and
store a
plurality of challenge codes for later use.
The personal unit can be used with virtually any existing; terminal of an
electronic
service without requiring the terminal to be modified or customized. For
instance, the
personal unit can be used with a standard telephone, whether <~ radio
telephone or land-
line telephone. The user can input the response code displayed on the personal
unit
through the telephone keypad or the personal unit can include a DTMF
transmitter for
direct input of the response code into the microphone of the telephone. It
follows that
the keypad of any service terminal (e.g., a data terminal connected to a
service computer)
can be used to input the response code. If some other input device is used in
a terminal,
such as an acoustic input, a inductively coupled input, an optical input,
radio receiver
(particularly if the terminal is by-passed and the response code; is
transmitted directly to
the authentication center), etc., the personal unit can include a compatible
output device.
In other words, the personal unit can be modified or equipped to be compatible
with
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existing or perspective terminals, rather than having to modify the terminals
to suit the
authentication procedure.
The same basic authentication procedure can be used for all services the user
might wish to engage, the procedure being modifiable to suit any specific
requirements
of the electronic service. The user may have one personal unit for all the
services he
may wish to subscribe to, or several personal units, each unit being usable
with one or
a subset of services to which the user has subscribed.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be described with reference to the attached-
drawing figures in which:
Figure 1 is a schematic diagram of an authentication pager system in
accordance
with the present invention;
Figure 1 A is a schematic diagram of an authentication pager system with
reference to specific communications in accordance with the present invention;
Figure 2 is a perspective view of a personal unit in accordance with the
present
invention; and
Figure 3 is a flowchart outlining the authentication procfas in accordance
with the
present rnventron.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hardware of the Stem
Referring to Figure 1, the present invention includes a personal unit 20 for
generating a response code, a terminal 22 for initiating service access and
conducting
service, and for inputting the response code to a service access network 24.
The service
access network transmits data between the terminal 22 and a service 26. The
terminal
22 can be a land-line telephone, a radio telephone, an ATM, a computer with a
modem
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(modulator/demodulator), a facsimile machine, or virtually any other type of
terminal
capable of receiving an input directly or indirectly from the personal unit 20
and relaying
information to a service node 26.
The service node 26 may be any form of electronic service, such as banking or
financial services, credit card services, long distance telephone services,
information
services, etc. The type of service provided is not germane to the present
invention. One
of the advantages of the personal unit 20 of the present invention is that it
can be used
for authenticating the user of any service.
In an exemplary embodiment, the authentication center 30, whether separate or
as part of the service node 26, includes a radio transnnitter, storage for one
or more
algorithms, and a comparator to compare the received response code to an
expected
response code. The authentication center 30 can be realized in the form of
additional
software added to a preexisting pager system or other radio communication
system. The
separate authentication center 30 enables many service nodes or networks to
use one
is authentication center 30. This permits changes in the authentication
procedure to be done
at one location for all applications and permits one authentication procedure
to be used
for more than one service, and perhaps all services to which a user has
subscribed.
The service access network 24 can be in the form of any communication system,
such as a public or private telephone network, telegraph, or other land-line
system,
cellular radio telephone network, or other radio communication network. The
form of
the service access network 24 can be in any form capable of transmitting
information
from the terminal 22 to the service node 26. The service access network 24 in
some of
the examples provided below is in the form of a preexisting tf:lephone
network.
The authentication challenge network 28 can be. the same network as the
service
2s access network 24, or preferably a distinct and separate network. The
authentication
challenge network 28 can be any communication system, such as a public or
private
telephone network, telegraph, or other land-line system, cellular radio
telephone network,
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or other radio communication network. The authentication challenge network 28
can be
in any form capable of transmitting information from the service node 26 (or
authentication center 30) to the personal unit 20. In one embodiment, the
authentication
challenge network 28 is a preexisting wide area pager system capable of
broadcasting a
personal unit identification number and additional information, such as at
least one
challenge code. Existing pager systems which can transmit at least the
telephone number
the user is being prompted to call have sufticient capabilities to function
with the personal
unit 20 disclosed herein. Any form of radio communication system can provide
the
optimum security offered by the present invention because only a specific
receiver
properly generate the expected response when the proper PIN or the like is
input in the
personal unit 20. However, the user can be required to manually input a
challenge code
provided over an interactive service access network 24.
In the exemplary embodiment of Figure 2, the personal unit 20 includes a
receiver
unit 21a for receiving the challenge code, and an algorithm unit 21b,
operatively
connected to the receiver unit 21a and preferably including an input device
for receiving
a user input, such as a security number, e.g., a PIN. The receiver unit 21a
can be in the
form of the radio receiver of a pager having a digital display capable of
displaying a
caller's telephone number or the like. The personal unit 20 can be essentially
a
conventional pager which is moditied to include, for example, an algorithm
unit 21b, an
input keypad 2Ic and optionally a dual tone multi-frequency (1DTMF) generator
21d (if
automated input of the displayed response code is preferred where the terminal
22 is
connected to some form of audio communications network). The personal unit 20
may
include a transmitter 21f in an embodiment where the service a<;cess network
24 includes
an radio uplink, or where the response code is directly sent to the
authentication center
30 or service node 26. The algorithm unit 21b calculates a response code in
accordance
with the received challenge code, an appropriate input security number and
optionally a
secret key (a secret number or code provided by the supplier of the personal
unit 20)
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entered into storage in the personal unit 20 at the time of subscription.
Algorithms of
this type are known in the art or readily derived therefrom. See, GSM 03.20,
Appendix
C.2, algorithm A3, for example. The specific algorithm used in a given
embodiment is
not germane to the present invention. A memory 21e is provided to store the
algorithms,
the secret key, received challenge codes and computer programming as a
specific
embodiment makes expedient. The personal unit 20 may be nnicroprocessor
driven.
This provides a triple check on the identity of the user, requiring
information
from three separate sources (user: PIN, service node or authentication center:
challenge
code, and provider of the personal unit: secret key), thereby increasing the
relative
security of the transaction against fraud or other unauthorized use.
In a preferred embodiment, the personal unit 20 is a separate unit, thereby
minimizing or avoiding the need to customize a communication device such as a
cellular
telephone. The receiver unit 21a, input device 21c, and the capacity for
performing the
necessary calculations exists in conventional cellular to°.lephones and
personal
communication units, allowing the present invention to be implemented through
software.
The challenge code can either be unique to a given transaction or broadcast,
for
example, to all such personal units in use at a given time. The response code
is to be
unique to each transaction in either scenario. Also, in either scenario, the
challenge
codes should be changed on a periodic or a random basis to provide additional
security
for transactions. Similarly, the user input, such as a PIN, can be updated at
the user's
discretion or on a regular basis. Even the algorithm can be changed from time
to time,
or more than one algorithm can be stored in the personal unit 20, which can be
either
cyclically used in a predetermined order or changed after a predetermined
number of
uses. As long as the authentication center 30 can determine what algorithm,
what secret
key (if used), and what user input should have been used for a given
transaction, the user
can be authenticated.
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The algorithm unit 21b calculates a response code based. on the received
challenge
code, the user input (e.g., PIN), and optionally the secret hey. Thus, for a
correct
response code to be generated, the challenge code, the user input and the
secret key (if
used) have to be in accordance with the expectations of the service node 26 or
authentication center 30 if access to the service is to be granted. The
service node 26
or the authentication center 30 is provided with enough information to be able
to
anticipate the proper response code. Thus, for a transaction to be authorized,
the user
must know the appropriate user input (e.g., PIN), be in possession of the
correct personal
unit 20 and receive the appropriate challenge code.
A conventional twelve button (0-9, * and i~) keypad 2lc is preferably provided-
for inputting the user input as shown in Figure 2. Alternatively, a reduced or
expanded
keypad can be used with lesser or greater security being afforded thereby. A
character
recognition device which can recognize a signature or other writing can be
used for the
user input device. Also, fingerprint or retinal scanner can be used for added
security in
appropriate situations.
For example, the challenge code may have 10 decimal digits, the secret key may
have 12 decimal digits, the PIN may have 4 decimal digits, and the response
code may
have 8 decimal digits.
Authentication Process
A user initiates a service access through terminal 22 by transmitting the
request
over a service access network 24 to a service node 26. The service node 26
does not
immediately initiate the services offered. Rather, it generates a challenge
code or causes
a challenge code to be generated in an authentication center 30. The challenge
code is
sent over an authentication challenge network 28 to the personal unit 20.
When the personal unit 20 receives an authentication challenge code, it
prompts
the user to input a PIN or other identifying information, and ,generates a
response code
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by an algorithm having the challenge code, an internal security code and the
PIN as
variable. Alternatively, several challenge codes can be received and stored in
the
personal unit 20, and the user prompted for the user input when attempting
access to an
electronic service. The user inputs a PIN, for example, via the keyboard 21c
of the
personal unit 20. However, known character recognition devices can be used to
recognize a signature, or writing generally, which is input on a pad via a
stylist. Other
possibilities include a finger print or retinal scan devices, though the
expense of these
devices makes a practical embodiment less likely except for transactions
requiring the
highest form of security.
The internally stored algorithm then generates a response code based on the
challenge code, the user input, and optionally a secret key.
The response code is either displayed on a display (Fig. 2) for manual input
to
terminal 22, or electronically, acoustically or optically input to terminal 22
which then
transparently transmits the response code over the service .access network 24
to the
service node 26. Alternatively or additionally, the response can be
transmitted over the
authentication network 28 to the authentication center 30 which then may send
the
response to the service node 26, or compare the response to an expected
response and
forward the result to the service node 26. If the response code: is
acceptable, the service
node 26 permits the user to access the services offered. The response code is
compared
to an expected response code, which, in exemplary embodiments, may be pre-
stored or
generated using the same algorithm and variables. Because the communication
links in
the authentication challenge network 28, and perhaps the service access
network 24 may
suffer from noise (e.g., radio interference), some tolerance rnay be given in
the result
of the comparison. In other words, the response code and the expected response
code
do not have to be exactly the same to gain access to the service, particularly
when using
an analog, rather than a digital, transmission format.
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With reference to the tlow chart of Figure 3, an exemplary authentication
process
begins at step S 10 where a user initiates communication to a service node 26
via the
service access network 24. This can be as simple as picking up the telephone
and dialing
an appropriate telephone number, which may be pre-stored in the personal unit
20. At
step S 12, the process may include entering a user number or identity, such as
used for
a data service. As shown at step S 14, the service access network 24
transparently
communicates an access request from the user to the service node 26. The
service node
26, in response to the access request, requests authentication via an
authentication
challenge network 28 by sending a challenge code (either generated in a
separate
authentication center 30 or in the service node 26) to the user's personal
unit 20, as
shown at step S 18. Alternatively, one or more challenge codes can be sent to
the
personal unit 20 in advance. The personal unit 20 may display a prompt to
prompt the
user to input, for example, a security code, such as a PIN, or the terminal 22
may
provide the prompt as shown in step 520. Upon entry of the user input, the
algorithm
unit 21b of the personal unit 20 calculates and sends a response: code either
to the display
or to a dual tone multi-frequency generator, or both as shown in step S22.
Other output
devices can be used, such as radio wave (e.g., radio transmitter or
transceiver), infrared,
visible or ultraviolet generators (e.g., LED's or semiconductor lasers),
electrically
inductive couplers (e.g., induction coils), or forms of acoustic devices other
than a
DTMF generator.
The user then either manually inputs the displayed response code to the
terminal
22, or the personal unit 20 directly inputs the response code in the case of a
different
type of output device. For example, when a dual tone multi-frequency (DTMF)
generator is used with a communication system, the user presents generated
tones to a
microphone of such a system.
The service access network 24 transparently transmits. the response code to
the
service node 26 which determines whether it is acceptable as shown in step
S24. If the
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authentication center 30 performs the comparison of the received response code
to the
expected response code, the service node 26 will transmit the response code to
the
authentication center 30. Alternatively, the personal unit 20 can send via
radio
transmission the response directly to the authentication center 30 and the
authentication
center 30 can inform the service node 26 of the results. if the response code
is not
acceptable, the user's access to the service is denied and the process returns
to either
initiating the entire process or re-requesting the identitication information
as shown in
step S26. Optionally, the system can disable the personal unit 2U if a
predetermined
number of denied access attempts occur or if the personal unit 20 has been
reported as
stolen.
If the response code is acceptable, the service is accessed and the user can
perform the desired, available functions through the service node 26.
With reference to Figure 1 A, the basic procedure is ea;amined with reference
to
specific, numbered communications of an exemplary embodiment.
(1) ENTER USERID: PTOEXAN.
(2) Service node 26 receives request for a service from PTOEXAN. This
USERID is connected to Patent and Trademark Oftice Examiner
Andersson. Service node 26 sends a request for authentication: "Please
authenticate this user: Examiner Andersson.'°
(3) Challenge code is sent to Examiner Andersson's authentication pager.
(4) ENTER PASSWORD, which is sent to the data terminal 22 from the
service node 26.
(5) Examiner Andersson enters PIN number to activate calculation of response
code in personal unit 20. Response code is shown on the display of the
personal unit 20, and then manually input t.o the data terminal 22.
Alternatively, the response code can be sent via a radio link directly to the
authentication center 30.
(6) The response code is sent from the service node 26 to the authentication
center 30.
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(7) Authentication center 30 compares the received response to the expected
response and sends a message to the service node 26 informing the node
authenticated/not authenticated.
(8) Authentication approved/not approved to the user.
As a concrete example of the present invention, a home banking application
will
be described. In this application, the intention is to transfer money from the
owner's
account to a different account, such as a creditor's account. The user can pay
his bills
at home using a telephone and a personal unit 20. In this example, all
authentication
steps performed by the user are manual. The resulting dialogue is as follows:
User: Initiates a telephone call by calling a payment service-
telephone number of a bank.
Bank: "Enter your account number."
User: "4219231459i~."
Bank: "Please enter the following digits into your authentication
unit - 1, 2, 3, 2, 8" (challenge code). Alternatively, if the
challenge code is broadcast or previously stored in the
personal unit 20, then this step is skipped.
"Please enter your personal identitication number."
User: Enters his PIN into the personal unit 20. The personal unit
20 presents a challenge response, e.g., "i9283746", on the
personal unit's display. The user enters " 19283746" on the
telephone keypad.
Bank: "Enter account number of account to receive payment."
35
User: "431395067811."
Bank: "Account of Ms. Jane Doe, Anytown, USA. Enter
amount."
User: "'$500.00."
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Bank: "$500.00 is credited to the account of Ms. Jane Doe.
Transaction reference number 123456."
User: Hangs up.
This procedure may be complicated by routines for interrupting if an error has
occurred, routines for handling more than one transaction during a single
call, routines
for using another home telephone, etc.
A second exemplary procedure involves charging for long distance calls using a
special service node (SSN). In this example, the authentication is provided
when
charging a long distance call through a long distance telephone company.
User: The special service node telephone is, e.g., with the prefix 900,
followed by the long distance telephone number to be called, e.g.,
900 555-1212 .
SSN: "Give ID and challenge response."
User: Enters PIN into a personal unit 20 (wh:ich has received a radio
transmitted challenge code) and the personal unit 20 presents a
challenge response on its display, e.g., "19283746." A button is
then pressed and the personal unit's speaker is held against a
microphone of the telephone giving an acoustical DTMF output to
the SSN, e.g., '°#0859032843#19283746#" which includes a
personal identity number and followed by a response to the
challenge code.
SSN: Authenticity of the response code is checked and, if acceptable, the
connection is provided.
The same personal unit 20 can be used for both the above transactions. A
more automatic transaction can be implemented. For instance, the personal unit
20 may
include a receiver and a DTMF transmitter, in which case, the user merely
initiates
access to a service and at a prompt inputs a user input, such a;s a PIN.
To avoid waiting for the paging system to transmit challenges over a wide area
paging network, for example, it is possible to transmit several (e.g., three)
challenge
codes which are stored in the personal unit 20 until used when a PIN is
entered to
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generate a response code. The response code subsequently generated is not to
be used
more than once if repeating an entry due to error.
The authentication center 30 can determine when to provide additional
challenge
codes to a personal unit 20 via a radio signal, because it receives the
responses in order
to perform the authentication. Alternatively, it the service node 26 receives
the
responses, the service node 26 requests the authentication center 30 to send
the next
expected response to the service node 26, so that the authentication center 30
can count
the number of generated~used response codes. As stated previously, an
authentication
center 30 may be combined with a service node 26 or may be independently
located and
used by several service nodes.
The present invention can be implemented for any suitable service node 26
using
existing networks without significant costs by setting up appropriate data
exchanges
between existing networks and service nodes. The response code may be used for
authentication using any terminal in any networks, provided the terminal is
capable of
transmitting data. The response code may be sent via the authentication
network 28
(e.g., via a radio signal).
According to one embodiment of the present invention, a method for
authentication is provided which can be used for all electronic services
subscribed by a
user without requiring numerous passwords to be remembered. To achieve this,
the
authentication network 30 is connectable to all electronic networks or service
nodes 26.
When a user addresses a particular service node 26, requesting a service, the
service
node 26 sends a request for authentication to the authentication center 30. At
reception
of the request for authentication of a user, the authentication center 30
generates a
challenge code which is sent to the ~~ser via the service node. 26. The user
may then
manually input the challenge code and a user input, such as a F'1N, into his
personal unit
20, to receive a response code, shown on the display of the personal unit 20.
The
response may then be manually input to the terminal 22 used for accessing the
service.
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An authenticity check may then be performed either by the authentication
center 30 or
by the service node 26.
The challenge code may also be sent to the personal unit 20 via radio from the
authentication center 30, or sent as DTMF tones, for example via a PSTN
telephone.
The response code may also be sent to the authentication centE:r 30 via radio
or sent as
DTMF tones, for example via a PSTN telephone.
This authentication method does not require any than~;es to existing
terminals.
The method allows the response code to be sent to the node 26 performing the
authenticity check in a way suitable to the service application. The PIN code
used to
activate the calculation of a response in the personal unit 20 is the only
"password" or
PIN that must be memorized by the user.
The present invention may, of course, be carried out in other specitrc ways
than
those set forth herein without departing from the spirit and the central
characteristics of
the invention. The present embodiments are, therefore, to be considered in all
respects
as illustrative and not restrictive, and all changes coming within the meaning
and the
equivalency range of the appended claims are intended to be embraced herein.
AMENDED SHEE i
