Abstract: Some embodiments are directed to a computation device configured to verify that an edit script is for transforming a first string to a second string. The edit script has match operations and difference operations as allowed edit operations. The computation device obtains a representation of the edit script and subsequently performs a validation computation. For each match operation, the computation device determines a character at a current position in the first string and a character at a current position in the second string, verifies that they match, increments the current position in the first string by one and increments the current position in the second string by one. For each difference operation, the computation device increments the current position in the first string and/or the current position in the second string by one.

Abstract: Some embodiments are directed to a computation device configured to verify that an edit script is for transforming a first string to a second string. The edit script has match operations and difference operations as allowed edit operations. The computation device obtains a representation of the edit script and subsequently performs a validation computation. For each match operation, the computation device determines a character at a current position in the first string and a character at a current position in the second string, verifies that they match, increments the current position in the first string by one and increments the current position in the second string by one. For each difference operation, the computation device increments the current position in the first string and/or the current position in the second string by one.

Abstract: The present invention relates to a method of converting an encrypted data set into an encryption of individual bits representing the data set. Further, the invention relates to a system for converting an encrypted data set into an encryption of individual bits representing the data set. A basic idea of the present invention is to provide a protocol in which it is possible to divide an encryption of a data set in the form of e.g. a biometric feature, such as a number x, where x?{0, 1, . . . , n?1}, into an encryption of respective bits x0, x1, . . . , xt?1 forming the number x, where t is the number of bits of the number n?1, without leaking any information about x or its bits x0, x1, . . . , xt?1. Hence, the present invention enables splitting of the encryption [[x]] into the respective encrypted bits [[x0]], [[x1]] . . . , [[xt?1]] forming the encrypted number x=?I=1n xi 2i.

Abstract: The present invention relates to a method of converting an encrypted data set into an encryption of individual bits representing the data set. Further, the invention relates to a system for converting an encrypted data set into an encryption of individual bits representing the data set. A basic idea of the present invention is to provide a protocol in which it is possible to divide an encryption of a data set in the form of e.g. a biometric feature, such as a number x, where x?{0, 1, . . . , n?1}, into an encryption of respective bits x0, x1, . . . , xt-1 forming the number x, where t is the number of bits of the number n?1, without leaking any information about x or its bits x0, x1, . . . , xt-1. Hence, the present invention enables splitting of the encryption [[x]] into the respective encrypted bits [[x0]], [[x1]], . . . , [[xt-1]] forming the encrypted number x=?I=1n xi 2i.

Abstract: The present invention relates to a method of converting an encrypted data set into an encryption of individual bits representing the data set. Further, the invention relates to a system for converting an encrypted data set into an encryption of individual bits representing the data set. A basic idea of the present invention is to provide a protocol in which it is possible to divide an encryption of a data set in the form of e.g. a biometric feature, such as a number x, where x?{0, 1, . . . , n?1}, into an encryption of respective bits x0, x1, . . . , xt-1 forming the number x, where t is the number of bits of the number n?1, without leaking any information about x or its bits x0, x1, . . . , xt-1 Hence, the present invention enables splitting of the encryption [[x]] into the respective encrypted bits [[x0]], [[x1]], . . . , [[xt-1]] forming the encrypted number x=?I=1n xi 2i.

Abstract: The present invention relates to a method and a system of securely computing a measure of similarity for at least two sets of data. A basic idea of the present invention is to securely compare two sets of encrypted data to determine whether the two sets of data resemble each other to a sufficient extent. If the measure of similarity complies with predetermined criteria, the two sets of data from which the encrypted sets of data originate are considered to be identical.

Abstract: The present invention relates to a method and a system of securely computing a measure of similarity for at least two sets of data. A basic idea of the present invention is to securely compare two sets of encrypted data to determine whether the two sets of data resemble each other to a sufficient extent. If the measure of similarity complies with predetermined criteria, the two sets of data from which the encrypted sets of data originate are considered to be identical.

Abstract: The present invention relates to a method of converting an encrypted data set into an encryption of individual bits representing the data set. Further, the invention relates to a system for converting an encrypted data set into an encryption of individual bits representing the data set. A basic idea of the present invention is to provide a protocol in which it is possible to divide an encryption of a data set in the form of e.g. a biometric feature, such as a number x, where x?{0, 1, . . . , n?1}, into an encryption of respective bits x0, x1, . . . , xt?1 forming the number x, where t is the number of bits of the number n?1, without leaking any information about x or its bits x0, x1, . . . , xt?1 Hence, the present invention enables splitting of the encryption [[x]] into the respective encrypted bits [[x0]], [[x1]], . . . , [[xt?1]] forming the encrypted number x=?I=1n xi 2i.

Abstract: Method of and device for querying of protected data structured in the form of a tree. A corresponding tree of node polynomials is constructed such that each node polynomial evaluates to zero for an input equal to an identifier assigned to a node name occurring in a branch of the data tree starting with the node in question. A tree of blinding polynomials and a tree of difference polynomials are constructed such that each polynomial in the tree of node polynomials equals the sum of the corresponding polynomial in the tree of blinding polynomials and the corresponding polynomial in the tree of difference polynomials. The blinding tree is given to a client, the difference tree to a server. By combining the outcomes of the evaluations of the client and the server, it is possible to identify nodes that match a given query.

Abstract: The invention introduces, in the framework of secure multiparty computation based on homomorphic threshold cryptosystems, a protocol and a special type of multiplication gate that can be realized in a surprisingly simple and efficient way using just standard homomorphic threshold ElGamal encryption. As addition gates are essentially for free, the conditional gate not only allows for building a circuit for any function, but actually yields efficient circuits for a wide range of tasks.

Abstract: An information storage system includes one or more information update terminals, a mapper, one or more partial-databases, and one or more query terminals, exchanging messages over a set of communication channels. An identifier-mapping mechanism provides (to an update terminal) a method for delegating control over retrieval of the data stored at the partial-databases to one or more mappers, typically operated by one or more trusted third parties. Update terminals supply information, that is stored in fragmented form by the partial-databases. Data-fragment identifiers and pseudonyms are introduced, preventing unauthorized de-fragmentation of information--thus providing compliance to privacy legislation--while at the same time allowing query terminals to retrieve (part of) the stored data or learn properties of the stored data. The mapper is necessarily involved in both operations, allowing data access policies to be enforced and potential abuse of stored information to be reduced.