Patent ID: 7539877

Claim:
A data management apparatus comprising: a management-data storage unit configured to store management-object data; a management-data verification-value storage unit configured to store a top value placed on the top of an n-branch data-management tree as a management-data verification value where n is an integer equal to or greater than two, said management-data storage unit being a different storage device than said management-data verification-value storage unit; and a data verification process unit configured to carry out a process to verify validity of said management-object data on the basis of said management-data verification value, said data verification processing unit including, a verification route determination unit configured to determine a verification route between said top of said n-branch data-management tree and said management-object data in the lowest level, and a verification unit configured to execute data verification based on the data of n-branch management tree sequentially along said verification route determined by verification route determination unit, wherein said n-branch data-management tree comprises a hierarchical structure having a lowest level containing said management-object data, and higher levels containing data that results from computation by using a irreversible function based on other data located on another hierarchical layer at a level directly subordinate to said specific hierarchical layer, each data containing at least two computation results from management-data verification values of a different branch directly subordinate to said specific hierarchical layer; and said top value is a result of computation by using said irreversible function based on data located on a hierarchical layer at the highest level of said n-branch data-management tree, said verification route being represented by a sequence of index values from nodes at respective hierarchical layers so that when said verification unit executes data verification, the verification unit evaluates data only along said verification route in said n-branch management tree, and not along other routes that are not described by said verification route.