Blacklisting of frequently used gesture passwords
View Patent ↗A method of maintaining a blacklist for gesture-based passwords is provided. A data store of vectors corresponding to gestures is maintained on a blacklist server. Upon receiving a new gesture based password, an electronic device converts the password to a vector and forwards that vector to the blacklist server. The blacklist server assigns the vector to one of a cluster of vectors each having low distance from one another. If the increase in the occurrences of the number of vectors in the cluster results in a blacklist threshold being exceeded, the cluster of vectors is inputted to the blacklist. A notification can be sent back to the electronic device if the forwarded vector is on the blacklist or is inputted to the blacklist.
1. A method implemented on a server for blacklisting gesture passwords, the method comprising:
receiving a vector from an electronic device, the vector representing a gesture password, wherein the gesture password comprises a set of one or more strokes, each stroke comprising a set of one or more points, the vector being a similarity-preserving vector generated by encrypting the set of one or more strokes using a set of slowly varying functions;
associating the received vector with a cluster of vectors each representing the same or similar gesture password based on a low distance from the received vector to the vectors in the cluster of vectors;
determining whether the association of the received vector with the cluster of vectors causes a number of vectors in the cluster to exceed a threshold value for a number of incidences of the same or similar vectors representing the same or similar gesture password;
when the number of vectors in the cluster exceeds the threshold value,
updating a blacklist stored on the server to include the vectors within the cluster; and
sending to the electronic device a notification that the gesture password has been blacklisted.
2. The method of claim 1 , wherein the vector is a non-invertible representation of the gesture password.
3. The method of claim 1 , wherein associating the received vector comprises using a density-based clustering algorithm to determine to which of the plurality of clusters of vectors the received vector belongs.
4. The method of claim 3 , wherein the density-based clustering algorithm is DBSCAN.
5. The method of claim 4 , wherein a parameter £ of the DBSCAN algorithm is equal to 0.3, and a parameter A of the DBSCAN algorithm is equal to 3.
6. The method of claim 1 , further comprising:
receiving a plurality of vectors from an input interface;
arranging the plurality of vectors into a plurality of clusters, in which each vector in each cluster has a low distance from each other vector in the same cluster.
7. The method of claim 6 , wherein the arranging of the plurality of vectors into clusters comprises using a density-based clustering algorithm to place each of the plurality of vectors into one of the plurality of clusters.
8. The method of claim 7 , wherein the clustering algorithm is DBSCAN.
9. The method of claim 8 , wherein a parameter £ of the DBSCAN algorithm is equal to 0.3, and a parameter Λ of the DBSCAN algorithm is equal to 3.
10. The method of claim 1 , wherein encrypting the set of one or more strokes using a set of slowly varying functions comprises:
for each stroke in the set of one or more strokes,
generating a d×n matrix B having the following properties
B
=
(
k
11
…
k
1
n
⋮
⋱
⋮
k
d
1
…
k
d
n
)
i
=
1
…
d
,
j
=
1
…
n
,
b
(
i
)
=
1
wherein each row element i of the matrix B is computed using a slowly varying function f bi defined on the interval [0, d−1] in the range of [0, 1], b(i) is the i th column vector of the matrix B, d is the number of dimensions (d is an even number) of the respective stroke, and n is the point number of the respective stroke;
transforming the matrix B into a d/2×n matrix B T having the following properties
B
T
=
(
c
11
…
c
1
j
⋮
⋱
⋮
c
i
1
…
c
i
j
)
i
=
1
…
d
2
,
j
=
1
…
n
,
wherein each element in the matrix B T is presented as a complex number which can be expressed as follows
c
i
j
=
k
i
j
+
j
·
k
(
i
+
d
.2
)
j
,
i
=
1
…
d
2
,
j
=
1
…
n
;
multiplying each column of the matrix B T by a corresponding point of the complex representation of the respective stroke z to obtain the vector, denoted {tilde over (z)}, as follows
{tilde over (z)}=B T ·z
wherein
z
(
P
i
)
=
x
(
P
i
)
+
j
·
y
(
P
i
)
,
z
=
(
z
(
P
1
)
⋮
z
(
P
n
)
)
wherein P is a point of the respective stroke, P(i) is the i th point, and n is the point number of the respective stroke.
11. A method implemented on an electronic device for updating a blacklist stored on a server, the method comprising:
receiving a gesture password via an input interface on the electronic device, wherein the gesture password comprises a set of one or more strokes, each stroke comprising a set of one or more points;
generating a vector representing the set of one or more strokes of the gesture password, the vector being a similarity-preserving vector generated by encrypting the set of one or more strokes using a set of slowly varying functions;
transmitting the vector, without the gesture password from which the at least one vector is generated, from the electronic device to the server for updating a blacklist stored on the server to include the vector;
receiving an indication from the server that the gesture password has been blacklisted;
outputting a notification to a user interface to select a new password.
12. The method of claim 11 , wherein the at least one vector is a non-invertible representation of the gesture password.
13. The method of claim 11 , wherein encrypting the set of one or more strokes using a set of slowly varying functions comprises:
for each stroke in the set of one or more strokes,
generating a d×n matrix B having the following properties
B
=
(
k
11
…
k
1
n
⋮
⋱
⋮
k
d
1
…
k
d
n
)
i
=
1
…
d
,
j
=
1
…
n
,
b
(
i
)
=
1
wherein each row element i of the matrix B is computed using a slowly varying function f bi defined on the interval [0, d−1] in the range of [0, 1], b(i) is the i th column vector of the matrix B, d is the number of dimensions (d is an even number) of the respective stroke, and n is the point number of the respective stroke;
transforming the matrix B into a d/2×n matrix B T having the following properties
B
T
=
(
c
11
…
c
1
j
⋮
⋱
⋮
c
i
1
…
c
i
j
)
i
=
1
…
d
2
,
j
=
1
…
n
,
wherein each element in the matrix B T is presented as a complex number which can be expressed as follows
c
i
j
=
k
i
j
+
j
·
k
(
i
+
d
.2
)
j
,
i
=
1
…
d
2
,
j
=
1
…
n
;
multiplying each column of the matrix B T by a corresponding point of the complex representation of the respective stroke z to obtain the at least one vector, denoted {tilde over (z)}, as follows
{tilde over (z)}=B T ·z
wherein
z
(
P
i
)
=
x
(
P
i
)
+
j
·
y
(
P
i
)
,
z
=
(
z
(
P
1
)
⋮
z
(
P
n
)
)
wherein P is a point of the respective stroke, P(i) is the i th point, and n is the point number of the respective stroke.
14. A server, comprising:
a hardware processor:
a memory coupled to the hardware processor, the memory storing executable instructions that, when executed by the hardware processor, cause the electronic device to:
receive a vector from an electronic device, the vector representing a gesture password, wherein the gesture password comprises a set of one or more strokes, each stroke comprising a set of one or more points, the vector being a similarity-preserving vector generated by encrypting the set of one or more strokes using a set of slowly varying functions;
associate the received vector with a cluster of vectors each representing the same or similar gesture password based on a low distance from the received vector to the vectors in the cluster of vectors;
determine whether the association of the received vector with the cluster of vectors causes a number of vectors in the cluster to exceed a threshold value for a number of incidences of the same or similar vectors representing the same or similar gesture password;
when the number of vectors in the cluster exceeds the threshold value,
update a blacklist stored on the server to include the vectors within the cluster; and
send to the electronic device a notification that the gesture password has been blacklisted.
15. An electronic device, comprising:
a hardware processor:
a memory coupled to the hardware processor, the memory storing executable instructions that, when executed by the hardware processor, cause the electronic device to:
receive a gesture password via an input interface on the electronic device, wherein the gesture password comprises a set of one or more strokes, each stroke comprising a set of one or more points;
generate a vector representing the set of one or more strokes of the gesture password, the vector being a similarity-preserving vector generated by encrypting the set of one or more strokes using a set of slowly varying functions;
transmit the vector, without the gesture password from which the at least one vector is generated, from the electronic device to a server for updating a blacklist stored on the server to include the vector;
receive an indication from the server that the gesture password has been blacklisted;
output a notification to a user interface to select a new password.
16. A non-transitory machine readable medium having tangibly stored thereon executable instructions for execution by a processor of a server, wherein the executable instructions, when executed by the processor, cause the electronic device to:
receive a vector from an electronic device, the vector representing a gesture password, wherein the gesture password comprises a set of one or more strokes, each stroke comprising a set of one or more points, the vector being a similarity-preserving vector generated by encrypting the set of one or more strokes using a set of slowly varying functions;
associate the received vector with a cluster of vectors each representing the same or similar gesture password based on a low distance from the received vector to the vectors in the cluster of vectors;
determine whether the association of the received vector with the cluster of vectors causes a number of vectors in the cluster to exceed a threshold value for a number of incidences of the same or similar vectors representing the same or similar gesture password;
when the number of vectors in the cluster exceeds the threshold value,
update a blacklist stored on the server to include the vectors within the cluster; and
send to the electronic device a notification that the gesture password has been blacklisted.
17. A non-transitory machine readable medium having tangibly stored thereon executable instructions for execution by a processor of an electronic device, wherein the executable instructions, when executed by the processor, cause the electronic device to:
receive a gesture password via an input interface on the electronic device, wherein the gesture password comprises a set of one or more strokes, each stroke comprising a set of one or more points;
generate at least one vector representing the set of one or more strokes of the gesture password, the at least one vector being a similarity-preserving vector such that similar gesture passwords are mapped to vectors having a low distance between each other, the at least one vector being generated by encrypting the set of one or more strokes using a set of slowly varying functions;
transmit the vector, without the gesture password from which the at least one vector is generated, from the electronic device to a server for updating a blacklist stored on the server to include the vector;
receive an indication from the server that the gesture password has been blacklisted;
output a notification to a user interface to select a new password.