Microsoft Technology Licensing, LLC

Vinod Vaikuntanathan

Panagiotis Voulgaris

Kristin E Lauter

Nishanth Chandran

Michael Naehrig

Melissa Erin Chase

Elisabeth Malmskog

A master public key is generated as a first set of lattices based on a set of attributes, along with a random vector. A master secret key is generated as a set of trap door lattices corresponding to the first set of lattices. A user secret key is generated for a user's particular set of attributes using the master secret key. The user secret key is a set of values in a vector that are chosen to satisfy a reconstruction function for reconstructing the random vector using the first set of lattices. Information is encrypted to a given set of attributes using the user secret key, the given set of attributes and the user secret key. The information is decrypted by a second user having the given set of attributes using the second user's secret key.

Attribute based encryption using lattices

An obfuscated policy data encryption system and method for re-encrypting data to maintain the confidentiality and integrity of data about a user when the data is stored in a public cloud computing environment. The system and method allow a user to specify in a data-sharing policy who can obtain the data and how much of the data is available to them. This policy is obfuscated such that it is unintelligible to the cloud operator and others processing and storing the data. In some embodiments, a patient species with whom his health care data should be shared with and the encrypted health care data is stored in the cloud in an electronic medical records system. The obfuscated policy allows the electronic medial records system to dispense the health care data of the patient to those requesting the data without disclosing the details of the policy itself.

User-controlled data encryption with obfuscated policy

Representations of polynomials a, s, t, eand ecan be provided. Values of coefficients of the polynomials can be limited, and can be computed using randomization techniques. A verification key can be generated to include representations of polynomials a, b, and c. Computation of b can include computing a product using a and s, and adding e. Computation of c can include computing a product using a and t, and adding e. A signing key can represent s and t. The signing key can be used to produce a message signature that can represent a sum of t and a product of s and m, with m being derived from a message to be signed. The verification key can be used to verify the signature by checking coefficient sizes of a polynomial represented by the signature, and of a checking polynomial derived from the verification key and the signature.

Digital signatures with error polynomials

A processor on a delegator receives an input upon which an expensive function is to be evaluated. The delegator incorporates the input into a request to perform a task that is different from evaluating the function. When the task is performed, it provides a secondary result that is observable by the delegator. The secondary result is different from an answer to the expensive function and can be verified by the delegator with less computational expense than evaluation of the expensive function. The task can be performed by the server only after the server has verifiably evaluated the function based on the input. Request data, that is indicative of the request to perform a task with the input incorporated therein is transmitted to the server for performance of the task. The delegator then receives a returned result from the server indicative of the server performing the task. The returned result has a value that reflects both an answer to which the server has evaluated the function, and whether the answer is verified as being correct.

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Seattle, WA, United States of America

Vinod Vaikuntanathan