Graphical password

A graphical password arrangement displays a predetermined graphical image and requires a user to "touch" predetermined areas of the image in a predetermined sequence, as a means of entering a password. The password is set by allowing the arrangement to display the predetermined areas, or "tap regions", to a user, and requiring the user to position these tap regions in a location and sequence within the graphical image, with which the user desires the password to be set at. These "tap regions" are then removed from the display, leaving the original image by itself. The arrangement then waits for an entry device (user) to select the "tap regions", as described above, for possible access to a protected resource.

TECHNICAL FIELD 
This invention relates generally to processing systems and specifically 
relates to resource-access control arrangements such as password 
arrangements. 
BACKGROUND OF THE INVENTION 
The use of passwords to control access to resources such as computers, 
databases, telecommunications facilities, etc., is well known and 
understood. Before being given access to a requested resource, a user is 
required to enter a valid password as a way of ensuring that the user is 
authorized to access the resource. Normally, the password is a word or 
some other sequence of alphanumeric characters. The nodal method of entry 
is to speak the word into a microphone or to key the sequence of 
characters in on a terminal or a telephone keyboard. 
Conventional alphanumeric passwords suffer from disadvantages, however. 
Firstly, they are difficult for the users to remember, particularly if 
they are arbitrary alphanumeric sequences rather than normal words. 
Secondly, they are relatively easy to compromise, particularly by the use 
of a computer that is programmed to automatically try all dictionary words 
or all permutations of some number of alphanumeric characters as passwords 
in an attempt to gain unauthorized access to a resource. 
To overcome these difficulties, recently new security arrangements have 
been developed that rely on sensing of a user's individual and not readily 
duplicated characteristics as a means of validating the user's identity. 
These include voice analyzers, retina scanners, fingerprint image 
analyzers, and face image analyzers. While quite effective in overcoming 
the disadvantages associated with conventional alphanumeric passwords, 
these arrangements have disadvantages of their own. Chief amongst them is 
their complexity and associated cost, which make their use impractical for 
most of applications. 
SUMMARY OF THE INVENTION 
This invention is directed to overcoming these and other problems and 
disadvantages of the prior art. Generally according to the invention, them 
is provided a graphical password arrangement, wherein a user seeking 
access to a resource is presented with a predetemined image on a visual 
display and is required to point to (e.g. touch) one or more predetermined 
positions on the displayed image (referred to herein as "tap regions") in 
a predetermined order as a way of indicating his or her authorization to 
access the resource. 
Specifically according to the invention as claimed, there is provided a 
graphical password arrangement and/or method. The arrangement comprises 
means for displaying a predetermined image, means for storing a 
predetermined number of predetermined positions in the predetermined image 
as a password, means responsive to a user for determining a user's 
selections of locations in the displayed image, means for determining 
whether the determined locations selected by the user correspond to the 
predetermined positions of the password, and means responsive to a 
determination of a lack of correspondence between the determined locations 
and the predetermined positions for denying the user access to a resource 
that is protected by the password. The method correspondingly comprises 
the steps of displaying a predetermined image, selecting locations in the 
displayed image under user control, determining whether the selected 
locations correspond to a predetermined number of predetermined positions 
in the predetermined image that are stored as a password, and denying the 
user access to the resource in response to a determination that 
correspondence is lacking between the selected locations and the 
predetermined positions. 
The invention possesses numerous advantages over the prior art. Firstly, 
people generally find images to be easier to recall than alphanumeric 
sequences, particularly images with personal meaning. Secondly, even a 
very coarse matrix of tap regions yields great security. For example, in 
an arrangement that uses a 3 inch-by-5 inch (7.5 cm -by- 12.5 cm) display 
with one-quarter inch square (6 mm-by- 6 mm) tap regions and that requires 
the user to touch three tap regions in the correct order, there are 13.6 
million possible combinations. In comparison, a four-digit password like a 
personal identification number (PIN) is one of only 10,000 possible 
combinations, and a three-letter password is one of only 17,000 possible 
combinations. Thirdly, in equipment that already includes a 
touch-sensitive or a graphics display, the graphical password arrangement 
is substantially no more difficult or expensive to implement than a 
conventional password arrangement. But even if the cost and complexity of 
a touch-sensitive or graphics display and associated software is factored 
in, the graphical password may be simpler and less costly to implement 
than the new security arrangements that were mentioned above. 
These and other advantages and features of the invention will become more 
apparent from the following description of an illustrative embodiment of 
the invention taken together with the drawing.

DETAILED DESCRIPTION 
FIG. 1 shows a general diagram of a processing system 10. Processing system 
may be any one of a wide variety of systems, such as a personal computer, 
a telecommunications terminal, a personal digital assistant, an entrance 
security system, a vehicle ignition control system, etc. Processing system 
10 is a program-controlled system. It includes a memory 12 that stores 
control programs and associated data, and a processor 11 that executes the 
programs. As is often conventional with such systems, processing system 10 
also includes a visual display screen 15 and one or more entry devices 14 
(such as a keyboard, a mouse, and/or a light pen or a touch pen) that are 
coupled to processor 11 by an input and output (I/O) interface 13. Display 
15 may be a touch-sensitive display screen, and hence itself may function 
as one of the entry devices 14. As described so far, processing system 10 
and its component elements 11-15 are conventional. 
According to the invention, processing system 10 includes a graphical 
password arrangement PASSWD 16, which in this illustrative example is 
implemented via a program and data stored in memory 12, and which controls 
user access to the application capabilities provided by processing system 
10. The functionality of PASSWD 16 is represented in flowchart form in 
FIGS. 2 and 3. 
Processing system 10 is initially provided to the user with the password 
function disabled. Upon power-up of system 10, execution of PASSWD 16 is 
invoked, at step 200 of FIG. 2, and PASSWD 16 checks whether the password 
function is enabled, at step 202. If the password function is not enabled, 
PASSWD 16 grants the user unconditional access to processing system 10 and 
ceases execution, at step 204. 
While using processing system 10, the user may request enablement of the 
password function or a new password by entering the proper command through 
an entry device 14. In response, execution of PASSWD 16 is invoked, at 
step 300 of FIG. 3, and PASSWD 16 prompts the user to provide a password 
image, at step 302. The user may provide an image in any one or more ways, 
such as by composing an image on display 15 via one or more entry devices 
14, scanning in an existing image via an entry device 14, or selecting one 
from among a plurality of images that have been loaded and stored in 
memory 12. PASSWD 16 receives the password image provided by the user and 
stores it in memory 12, at step 304. It then displays the password image 
on display 15, at step 306. 
Alternatively, the password image may be predefined, and PASSWD 16 skips 
steps 302 and 304 and proceeds from step 300 directly to step 306. 
Following step 306, PASSWD 16 prompts the user to select the size and the 
number of tap regions that will make up the graphical password, at step 
308. Tap regions are positions in the displayed password image. 
Illustratively, each tap region is a rectangle no larger than 10% of the 
password image size, and the graphical password consists of at least two 
tap regions. In response to receiving the user's selection, at step 310, 
PASSWD 16 displays the selected number of sequentially-numbered tap 
regions of the selected size along with the password image, at step 312. 
The tap regions may be displayed in a row along an edge of display 15, or 
arbitrarily positioned over the password image. 
Alternatively, the number and size of tap regions may be predefined, and 
PASSWD 16 skips steps 308 and 310 and proceeds directly from step 306 to 
step 312. 
An illustrative example of the state of display 15 following step 312 is 
shown in FIG. 4, where numeral 400 designates the password image and 
numeral 401 designates the tap regions. 
Following step 312, PASSWD 16 prompts the user to select a tap region 401 
and to position it within password image 400, at step 314. The user 
performs these functions via one or more entry devices 14, such as by 
manipulating a cursor via a keyboard, pointing and dragging the cursor 
with a mouse, or tapping and sliding on display 15 with a light pen or a 
touch pen. If display 15 is a touch-sensitive screen, the user may perform 
the functions by tapping and sliding on display 15 with a finger. PASSWD 
16 waits until the user makes a location selection on display 15 via an 
entry device 14, at step 316, and determines the coordinates of the 
selected location, at step 318. It then determines whether the entry 
device 14 is located on a tap region 401, that is, whether a tap region 
401 has been properly selected, at step 320. If not, PASSWD 16 returns to 
step 314 to repeat the instructions to the user. 
If it is determined at step 320 that a tap region 401 has been properly 
selected, PASSWD 16 tracks the movement of entry device 14 across display 
15 and moves the selected tap region 401 along with the entry device 14, 
at step 322, while checking for release of the selected tap region 401 by 
entry device 14, at step 324. Hence, entry device 14 serves to move the 
tap region 401 relative to the displayed predetermined image 400. When it 
determines that entry device 14 has released the selected tap region 401, 
PASSWD 16 stores the sequence number of the selected tap region 401 and 
the position coordinates of the location within password image 400 where 
it had been released, at step 326. PASSWD 16 then checks whether the user 
has indicated completion of password selection, at step 330. 
Illustratively, in the example of FIG. 3, the user may indicate completion 
of password selection by selecting a displayed "done" indicator 402 via 
entry device 14. If the user has not indicated completion, PASSWD 16 
returns to step 316 to await re-selection of a tap region 401. If the user 
has indicated completion, PASSWD 16 marks the stored tap region sequence 
numbers and position coordinates in memory 12 as the new password, at step 
332, enables the password function, at step 334, and then ends its 
execution, at step 336. 
Alternatively, step 334 may be performed not by PASSWD 16 but manually by a 
user, via interaction with a separate control function of processing 
system 10. 
Returning to FIG. 2, the next time that processing system 10 is powered up, 
execution of PASSWD 16 is again invoked at step 200, and this time PASSWD 
16 determines at step 202 that the password function is enabled. In 
response, PASSWD 16 retrieves and displays on display 15 the stored 
password image 400 without also displaying tap regions 40 1, at step 206. 
An illustrative example of the state of display 15 following step 206 and 
corresponding to FIG. 4 is shown in FIG. 5. PASSWD 16 also retrieves the 
total number of tap regions 401 that make up the password, at step 208. 
PASSWD 16 then waits until the user makes a location selection on display 
15 with entry device 14, at step 210, and it obtains and stores the 
coordinates of the selected location, at step 2 12. Hence, entry device 14 
serves to identify, under the user's control, the location selected by the 
user. Following a selection, PASSWD 16 checks whether the number of 
selected locations equals the number of tap regions 401 that make up the 
password, at step 214. If not, PASSWD 16 returns to step 210 to await 
another sequential selection; if so, PASSWD 16 proceeds to compare the 
coordinates of each sequentially-selected location against the coordinates 
of the positions of the corresponding sequentially-numbered tap region 401 
within the password image 400 to determine if the selected location lies 
within the corresponding tap region 401, at steps 216-220. If it is 
determined at step 218 that the sequence of selected locations 
sequentially corresponds to the sequence of tap regions, entry of the 
password has been successful, and PASSWD 16 grants the user access to 
processing system 10 and ends its execution, at step 226. 
If each selected location does not lie within the corresponding tap region 
401 in password image 400, entry of the password has failed, and PASSWD 16 
checks whether a maximum allowed number of tries at entering the password 
has been exhausted, at step 222. Illustratively, three tries are allowed. 
If the maximum number of tries has not been exhausted, PASSWD 16 indicates 
failure to the user and prompts the user to try again, at step 224. PASSWD 
16 then returns to step 210 to await the user's set of selections. But if 
it is determined at step 222 that the maximum number of tries has been 
exhausted, PASSWD 16 denies the user access to processing system 10, 
illustratively by turning power off in processing system 10, and ends its 
execution, at step 228. 
Of course, various changes and modifications to the illustrative embodiment 
described above will be apparent to those skilled in the art. For example, 
a password may comprise a plurality of different images, with each image 
containing one (or more) of the tap regions that make up the password. 
Thus, a different image would be displayed after each tap (i.e., 3 images, 
one tap/image). Or, the password may additionally require that particular 
tap regions be tapped at particular times. For example, the graphical 
image could be a moving image, such as a short cartoon, requiring the user 
to click and tap at right locations at the right time. Also, the password 
image could be a blank screen (i.e., no image), requiring the user to just 
remember the location of the tap regions by "dead reckoning" (presumably 
using extra-large tap regions). Such changes and modifications can be made 
without departing from the spirit and the scope of the invention and 
without diminishing its attendant advantages. It is therefore intended 
that such changes and modifications be covered by the following claims.