Coinbase Il Rd Ltd.

Bar-ilan University

Unbound Tech Ltd.

Samuel Ranellucci

Yehuda Lindell

In certain embodiments, shares related to an output of a function having multiple shares of a secret as input may be computed. In some embodiments, with respect to initial key shares of a key that are collectively held by multiple parties, an output of an arithmetic function (performed on an initial key share of the initial key shares) may be received from each of the multiple parties. The outputs from the multiple parties may be provided as input for a Multi-Party Computation (MPC) process, where the MPC process outputs final key shares in connection with the outputs from the multiple parties being provided as input for the MPC process. With respect to each party of the multiple parties, a final key share of the final key shares may be sent to the party.

System and method for performing key operations during a multi-party computation process

The subject matter discloses computer-implemented method performed during a multi-party computation (MPC) process performed between multiple parties, said method comprising, the multiple parties executing a pre-processing phase and obtain values of correlated random variables to be used in an MPC process, the parties periodically verifying the correctness of the correlated random variables by exchanging information between the multiple parties, refreshing the values of the correlated random variables in each of the multiple parties, wherein no party of the multiple parties has access to values of the correlated random variables stored in another party of the multiple parties during the verifying and refreshing processes, the multiple parties using the correlated random variables during the MPC process after verifying a correctness of the correlated random variables.

Method for performing a preprocessing computation during a proactive MPC process

A method of performing cryptographic key exchange while overcoming a malicious adversary party using a multi-party computation (MPC) process performed by the multiple parties, where the parties hold initial shares of a secret used an as exponentiation of the key exchange, where the parties do not reveal the initial shares during the entire process, and where arithmetical computations are performed on the initial shares and on random values outputted during MPC processes.

System and method for performing key exchange while overcoming a malicious adversary party

A computerized system and method for obtaining a post-quantum security scheme, generating a one-time use signing key split into shares, each share of the one-time use signing key is stored in one computerized device of the multiple computerized devices, generating shares of a verification key using a function receiving a share of the signing key, generating a data structure, where each node of the data structure is associated with a share of the verification key, signing a message using the shares of the one-time use signing key, revealing the share of the verification key, and reconstructing at least a portion of the data structure to validate that the revealed share of the verification key is associated with the correct node of the data structure.

System and method for securing data in a quantum computing environment using multi-party computation

A method for signing a message, comprising performing a first Multi-Party Computation (MPC) process by multiple parties to compute a pseudorandom function, an input of the first MPC process comprises shares of a private signing key, each share is held by each party, the message is an input value to the pseudorandom function. The output of the first MPC process comprises multiple pairs of shares, each party holding a pair of shares, wherein each pair comprises a first value used for the MPC signing process and a second verifying value used for verifying correctness of the values provided by the multiple parties for the MPC signing process, and computing the signature on the message by performing an MPC signing protocol on the message, the MPC signing protocol receives as input shares of the output of the pseudorandom function from the multiple parties, and the message to be signed.

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Petah Tiqva, Israel

Samuel Ranellucci