Application-specific biometric templates
Disclosed are techniques for transforming a biometric template so that each application uses a unique template format. One transformed template cannot be successfully matched to a second template extracted from the same biologic entity unless the second template is transformed so that its format is identical to that of the first template. Thus a template generated in a format corresponding to application A could not be used to authenticate a user for application B because the enrollment database for application B would have a different format than the enrollment database for application A.
1 . A method for securing access to protected applications, the method comprising:
receiving a predetermined biometric template;
transforming said predetermined biometric template to generate a transformed biometric template having a unique format corresponding to a particular biometric application, the transforming comprising at least one of altering the position of every bit of data of the biometric template using derangement permutations and exclusive-oring the data of the biometric template with a mask function;
storing said transformed biometric template in a storage;
receiving a first biometric template;
transforming said first biometric template using a first transforming function to create a first transformed biometric template, the first transformed biometric template having the unique format corresponding to the particular biometric application; and
comparing said first transformed biometric template with said stored transformed biometric template.
2 . The method of claim 1 , wherein said transforming said first biometric template to create a first transformed biometric template further comprises applying a first transforming function to said first biometric template to create said first transformed biometric template.
3 . The method of claim 1 , wherein said comparing further comprises determining that said first transformed biometric template is approximately equal to said transformed biometric template.
4 . The method of claim 3 further comprising enabling access to a protected application responsive to said comparing.
5 . The method of claim 1 , further comprising indexing said transformed template by a key.
6 . The method of claim 1 , further comprising creating a second transformed biometric template by applying a second transforming function to said first biometric template.
7 . The method of claim 6 , wherein said second transformed biometric template is not approximately equal to said first transformed biometric template created by applying said first transforming function to said first biometric template.
8 . The method of claim 1 , further comprising receiving a second transformed biometric template created from a second transforming function, wherein said second transformed biometric template is not approximately equal to said first transformed biometric template.
9 . The method of claim 1 , further comprising generating a plurality of biometric templates corresponding to one entity.
10 . The method of claim 1 , wherein said transforming function comprises:
receiving data unique to a user; and
transforming said data into a transformed biometric format by applying an encoding and transforming function to said data.
11 . The method of claim 6 , wherein said second transforming function further comprises:
receiving said first transformed biometric template in a first format;
transforming said first transformed biometric template in said first format into said second transformed biometric template in a second format by applying said second transforming function.
12 . The method of claim 11 , wherein said second format is not approximately equal to said first format.
13 . The method of claim 1 , wherein at least one of a plurality of transforming functions is maintained by a template authority.
14 . The method of claim 13 , wherein said at least one of a plurality of transforming functions is maintained in secret.
15 . The method of claim 11 , further comprising receiving a request for transformation of a transformed template from said first format to said second format.
16 . The method of claim 15 , further comprising receiving the transformed template as authorization to convert said first transformed template into said second transformed template.
17 . The method of claim 11 , wherein a plurality of said first transformed templates in said first format are transformed periodically into a plurality of said second transformed templates of said second format.
18 . The method of claim 6 , wherein said second transforming function incorporates a secret transformation key.
19 . A system for securing access to protected applications comprising:
a receiver for receiving a biometric template;
computer-executable instructions for:
receiving a predetermined biometric template;
transforming said predetermined biometric template to generate a transformed biometric template having a unique format corresponding to a particular biometric application, the transforming comprising at least one of altering the position of every bit of data of the biometric template using derangement permutations and exclusive-oring the data of the biometric template with a mask function;
storing said transformed biometric template in a storage;
receiving a first biometric template;
transforming said first biometric template using a first transforming function to create a first transformed biometric template, the first transformed biometric template having the unique format corresponding to the particular biometric application; and
comparing said first transformed biometric template with said stored transformed biometric template; and
a database for storing said transformed biometric template templates.
20 . The system of claim 19 , wherein said computer-executable instructions further comprise instructions for determining that said first transformed biometric template is approximately equal to said transformed biometric template.
21 . The system of claim 20 , wherein said computer-executable instructions further comprise instructions for enabling access to a protected application responsive to the comparing.
22 . The system of claim 19 , wherein said computer-executable instructions further comprise creating a second transformed biometric template by applying a second transforming function to said first biometric template.
23 . The system of claim 22 , wherein said second transformed biometric template is not approximately equal to said first transformed biometric template created by applying a first transforming function to said first biometric template.
24 . The system of claim 19 , further comprising a receiver for receiving a second transformed biometric template created from a second transforming function wherein said second transformed biometric template is not approximately equal to said first transformed biometric template.
25 . The system of claim 19 , wherein a plurality of biometric templates are generated corresponding to one entity.
26 . The system of claim 19 , further comprising a receiver for receiving data unique to a user.
27 . The system of claim 26 , further comprising computer-executable instructions for transforming said data into a transformed biometric format by applying an encoding and transforming function to said data.
28 . The system of claim 24 , further comprising:
a receiver for receiving said first transformed biometric template in a first format; and
computer-executable instructions for transforming said first transformed biometric template in said first format into said second transformed biometric template in a second format by applying said second transforming function.
29 . The system of claim 28 , wherein said second format is not approximately equal to said first format.
30 . The system of claim 28 , further comprising a template authority.
31 . The system of claim 30 , wherein said template authority maintains said first and second transforming functions in secret.
32 . The system of claim 28 , wherein the receiver is adapted to receive a request for transformation of a transformed template from said first format to said second format.
33 . The system of claim 19 , wherein the receiver is adapted to receive the transformed template as authorization to convert said first transformed template into said second transformed template.
34 . The system of claim 28 , further comprising computer-executable instructions for periodically transforming a plurality of transformed templates in said first format into a plurality of second transformed templates in said second format.
35 . The method of claim 34 , wherein said second transforming function incorporates a secret key.
36 . A computer-readable medium comprising computer-executable instructions for performing the method of claim 1.