Method and system for compiling a multi-source database of composite investor-specific data records with no disclosure of investor identity
A system and method are disclosed for compiling a database of investor-related data by gathering and linking customer-specific data records from multiple unaffiliated financial institutions, where such data records are coded in such a manner that the database compiler is enabled to link, across data providers and/or time periods, data records that pertain to the same investor without being provided any information that reveals the identity of any investor.
1. A method of compiling an electronic database of entity-specific information maintained by a plurality of unaffiliated institutions, comprising the steps of:
providing each institution with a computer-based device having a software module that executes an algorithm to create surrogate entity codes,
wherein each surrogate entity code (i) corresponds to a unique value of entity identification information maintained by such institution, and (ii) is generated in such manner that no entity identification information can be derived from such surrogate entity code,
wherein the algorithm creates each surrogate entity code by executing, in succession, (i) an irreversible transformation of the corresponding value of the entity identification information, and then (ii) a reversible transformation of the output values of the irreversible transformation, and
wherein, with respect to any specific value of the entity identification information, the algorithms executed by the computer-based devices yield (i) output values from the irreversible transformations that are the same for all institutions, and (ii) output values from the reversible transformations that are different for every institution but are convertible to a common surrogate entity code;
receiving from each institution a set of data records, each of which contains information that pertains to a particular entity and is associated with a surrogate entity code, and which is free of entity identification information;
installing in the database the data records provided by the plurality of institutions; and
linking the data records at the entity-specific level by converting the different surrogate entity codes from the different institutions into common surrogate entity codes and then, with respect to each common surrogate entity code, logically associating all data records with which such common surrogate entity code is associated.
2. The method of claim 1 wherein the entity identification information is a person's social security number.
3. The method of claim 1 wherein the entity identification information is any one of a person's social security number and any other entity's taxpayer ID.
4. The method of claim 1 wherein the entity identification information is any one of the entity's social security number, taxpayer ID, and mailing address.
5. The method of claim 1 wherein the entity identification information is any combination of information elements that uniquely identifies specific entities that are the subject of the database.
6. The method of claim 1 wherein the irreversible transformation is a cryptographic hash function.
7. The method of claim 6 wherein a seed is used with the cryptographic hash function.
8. The method of claim 7 wherein the seed is created and distributed to the institutions by a trusted third party.
9. The method of claim 1 wherein the reversible transformation is a cryptographic encryption function.
10. The method of claim 9 wherein a symmetric key is used to seed the cryptographic encryption function.
11. The method of claim 9 wherein an asymmetric key is used to seed the cryptographic encryption function.
12. The method of claim 1 wherein the output values resulting from the reversible transformation function as the surrogate entity codes.
13. The method of claim 12 wherein surrogate entity codes are converted into common surrogate entity codes by reversing the reversible transformation to obtain the output values of the irreversible transformation, and those output values function as the common surrogate entity codes.
14. The method of claim 12 wherein surrogate entity codes are converted into common surrogate entity codes by (i) first reversing the reversible transformation to obtain the output values of the irreversible transformation, and then (ii) performing a second transformation of those output values to yield common surrogate entity codes, generated in such manner that the surrogate entity codes cannot be derived from them.
15. The method of claim 14 in which the second transformation is an irreversible transformation.
16. The method of claim 15 wherein the irreversible transformation is a cryptographic hash function.
17. The method of claim 16 wherein a seed is used with the cryptographic hash function.