Homomorphic encryption using smart contracts

A method of cryptography for securing data on a blockchain, comprising:

• using at least one hardware processor executing a code for enabling uploading secured data to a blockchain, said code comprising code instructions for:
• obtaining at least one encrypted data item, encrypted with a public key compliant with a homomorphic encryption mechanism;
• feeding the at least one encrypted data item into a computational process that is executed by at least one processor of a network connected offload-server that executes the computational process off the blockchain, and is in network communication with network nodes hosting the blockchain and a smart contract, said computational process manipulates the at least one encrypted data item with computations compliant with the homomorphic encryption mechanism and provides at least one encrypted outcome;
• obtaining the at least one encrypted outcome of the computational process from the network connected offload-server;
• and providing said at least one encrypted outcome toa-said smart contract for posting on a blockchain, wherein the at least one encrypted outcome is compliant with the homomorphic encryption mechanism and decrypted with a private key corresponding to the public key, and
• wherein the at least one encrypted outcome is obtained as an aggregation of sub-outcomes obtained from the plurality of off-loading smart contracts.

A non-transitory medium storing program instructions for securing data on a blockchain, which, when executed by at least one processor, cause the at least one processor to enable uploading secured data to a block chain, said program instructions comprising:

• program instructions to obtain at least one encrypted data item, encrypted with a public key compliant with a homomorphic encryption mechanism;
• program instructions to feed the at least one encrypted data item into a computational process that is executed by at least one processor of a network connected offload-server that executes the computational process off the blockchain, and is in network communication with network nodes hosting the blockchain and a smart contract, said computational process manipulates the at least one encrypted data item with computations compliant with the homomorphic encryption mechanism and provides at least one encrypted outcome;
• program instructions to obtain the at least one encrypted outcome of the computational process from the network connected offload-server;
• and program instructions to provide said at least one encrypted outcome to said smart contract for posting on a blockchain, wherein the at least one encrypted outcome is compliant with the homomorphic encryption mechanism and decrypted with a private key corresponding to the public key, and
• wherein the at least one encrypted outcome is obtained as an aggregation of sub-outcomes obtained from the plurality of off-loading smart contracts.