Sap Se

Mirko Schaefer

Axel Schroepfer

Kilian Becher

Marcel Muth

Disclosed herein are system, method, and computer program product embodiments for pooling requirements, such as placing of multiple purchase orders, while preserving the privacy of the requirements provided by requesters placing the orders. The approach involves receiving first encrypted information comprising a first request from a first client and second encrypted information comprising a second request from a second client. An encrypted intersection result of the first request and the second request can then be calculated using the first encrypted information and the second encrypted information, in their encrypted form without the need to decrypt either.

Method, system, and non-transitory computer readable storage device for a pooling requirement while preserving privacy

The present disclosure involves systems, software, and computer implemented methods for a efficient distributed secret shuffle protocol for encrypted database entries using independent shufflers. Each of multiple data providers provides an encrypted secret input value. A set of shuffling clients, independent of the data providers, participate with a service provider in a secret shuffling of the encrypted secret input values. The protocol includes generation and exchange of random numbers, random permutations and different blinding values. A last protocol step includes using homomorphism, for each client, to perform computations on intermediate encrypted data to homomorphically remove a first blinding value and a second blinding value, to generate a rerandomized encrypted secret input value. As a result, the rerandomized encrypted secret input values are generated in an order that is unmapped to an order of receipt, at the service provider, of the encrypted secret input values.

Efficient distributed secret shuffle protocol for encrypted database entries using independent shufflers

The present disclosure involves systems, software, and computer implemented methods for a communication-efficient secret shuffle protocol for encrypted data based on homomorphic encryption and oblivious transfer. A service provider and multiple clients participate in a secret shuffle protocol of randomly shuffling encrypted client-specific secret input values. The protocol includes generation and exchange of random numbers, random permutations and different blinding values, including use of an oblivious transfer mechanism. A last protocol step includes using homomorphism, for each client, to perform computations on intermediate encrypted data to homomorphically remove a first blinding value and a second blinding value, to generate a client-specific rerandomized encrypted secret input value. As a result, the client-specific rerandomized encrypted secret input values are generated in an order that is unmapped to an order of receipt, at the service provider, of the encrypted secret input values.

Communication-efficient secret shuffle protocol for encrypted data based on homomorphic encryption and oblivious transfer

A producer may supply amounts xof a good to a plurality of consumers Cin a series of transactions and be subject to a mass balancing verification protocol after every K transactions. A producer platform may compute K random shares (rthrough r) of a random value r, publish blinded amounts trepresenting x+rto a secure, distributed transaction ledger, and transmit an encrypted rto consumer Cusing an asymmetric cryptosystem. A consumer platform may receive and decrypt r(while the consumer Ci actually receives an amount {circumflex over (x)}of the good from the producer), compute {circumflex over (x)}+rand generate a fraud alert signal if it differs from the published t. The consumer platform may also transmit an encrypted rolling sum value to a next consumer C. A verifier platform may, after K transactions, execute the mass balance verification protocol to determine a total amount of the good that the producer had collectively supplied to the consumers C. The verifier platform may also generate a fraud alert signal when appropriate based on the total amount and a maximum allowed amount.

Distributed ledger based mass balancing via secret sharing

The present disclosure involves systems, software, and computer implemented methods for a efficient distributed secret shuffle protocol for encrypted database entries using dependent shufflers. Each of multiple clients provides an encrypted client-specific secret input value. A subset of clients are shuffling clients who participate with a service provider in a secret shuffling of the encrypted client-specific secret input values. The protocol includes generation and exchange of random numbers, random permutations and different blinding values. A last protocol step includes using homomorphism, for each client, to perform computations on intermediate encrypted data to homomorphically remove a first blinding value and a second blinding value, to generate a client-specific rerandomized encrypted secret input value. As a result, the client-specific rerandomized encrypted secret input values are generated in an order that is unmapped to an order of receipt, at the service provider, of the encrypted secret input values.

Efficient distributed secret shuffle protocol for encrypted database entries using dependent shufflers

The present disclosure involves systems, software, and computer implemented methods for a verifiable communication-efficient secret shuffle protocol for encrypted data based on homomorphic encryption. A service provider and multiple clients participate in a secret shuffle protocol of randomly shuffling encrypted client-specific secret input values. The protocol includes generation and exchange of random numbers, random permutations, different blinding values, and use of random secret-shares. A protocol step includes homomorphic operations to shuffle encrypted secret input values so that resulting encrypted secret input values are rerandomized and in a shuffled sequence that is unmapped to an order of receipt by the service provider of the encrypted secret input values.

Verifiable secret shuffle protocol for encrypted data based on homomorphic encryption and secret sharing

The present disclosure involves systems, software, and computer implemented methods for verifying encrypted data provider data on a public storage medium. One example method includes receiving a verification request to verify encrypted data provider data stored on a public storage medium. Public storage medium entries relevant to the verification request are identified and retrieved. A homomorphic cryptosystem is used to homomorphically calculate a first encrypted target function result based on encrypted data provider data. The homomorphic cryptosystem and a verifying entity cryptosystem are used to re-encrypt the first encrypted target function result to generate a second encrypted target function result that is encrypted under the verifying entity cryptosystem and not encrypted under the homomorphic cryptosystem. The second encrypted target function result is provided to the verifying entity, to enable the verifying entity to decrypt the second encrypted target function result and verify a target function result.

Verifying a result using encrypted data provider data on a public storage medium

The present disclosure involves systems, software, and computer implemented methods for a communication-efficient secret shuffle protocol for encrypted data based on homomorphic encryption. A service provider and multiple clients participate in a secret shuffle protocol of randomly shuffling encrypted client-specific secret input values. The protocol includes generation and exchange of random numbers, random permutations and different blinding values. A last protocol step includes using homomorphism, for each client, to perform computations on intermediate encrypted data to homomorphically remove a first blinding value and a second blinding value, to generate a client-specific rerandomized encrypted secret input value. As a result, the client-specific rerandomized encrypted secret input values are generated in an order that is unmapped to an order of receipt, at the service provider, of the encrypted secret input values.

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Dresden, Germany

Mirko Schaefer