Zero knowledge proof of smart contract computation using private input

A method by a network device implementing a second peer of a distributed ledger to provide trusted execution of a smart contract that uses private data accessible to the second peer but not accessible to a first peer of the distributed ledger, the method comprising:

• receiving a request to execute the smart contract, a proving key, and an identifier of a subroutine of the smart contract for which proof of computation is requested, wherein the subroutine uses the private data;
• beginning execution of the smart contract;
• detecting, during the execution of the smart contract, the subroutine;
• obtaining a program adapted for a zero-knowledge proving scheme that was generated based on the subroutine, wherein the program adapted for the zero-knowledge proving scheme includes logic to verify that the private data corresponds to manipulation detection codes of the private data;
• executing the subroutine;
• generating a zero-knowledge proof of computation of the subroutine using the zero-knowledge proving scheme based on the program adapted for the zero-knowledge proving scheme, a public input to the program adapted for the zero-knowledge proving scheme, a private input to the program adapted for the zero-knowledge proving scheme, and the proving key;
• resuming the execution of the smart contract after the subroutine to generate a full execution result of the smart contract;
• providing, to the first peer, the zero-knowledge proof and the public input;
• and
• providing the full execution result to a consensus mechanism of the distributed ledger.

A set of non-transitory machine-readable media having computer code stored therein, which when executed by a set of one or more processors of a network device implementing a first peer of a distributed ledger, causes the first peer to perform operations for providing trusted execution of a smart contract that uses private data accessible to a second peer of the distributed ledger but not accessible to the first peer, the operations comprising:

• receiving a request to execute the smart contract;
• beginning execution of the smart contract;
• detecting, during the execution of the smart contract, a subroutine of the smart contract that uses the private data;
• obtaining a program adapted for a zero-knowledge proving scheme that was generated based on the subroutine, wherein the program adapted for the zero-knowledge proving scheme includes logic to verify that the private data corresponds to manipulation detection codes of the private data;
• obtaining a verification key that was generated based on the program adapted for the zero-knowledge proving scheme;
• generating a partial execution result of the smart contract;
• providing an identifier of the subroutine to the second peer;
• obtaining a zero-knowledge proof of computation of the subroutine and a public input to the program adapted for the zero-knowledge proving scheme, wherein the zero-knowledge proof was generated by the second peer based on a proving key that was generated based on the program adapted for the zero-knowledge proving scheme;
• determining whether the zero-knowledge proof is valid using the zero-knowledge proving scheme based on the public input and the verification key;
• determining whether the public input is valid;
• restoring an execution state of the smart contract using the partial execution result in response to a determination that the zero-knowledge proof and the public input are valid;
• applying effects of the subroutine;
• resuming the execution of the smart contract after the subroutine to generate a full execution result of the smart contract;
• and
• providing the full execution result to a consensus mechanism of the distributed ledger.

A set of non-transitory machine-readable media having computer code stored therein, which when executed by a set of one or more processors of a network device implementing a second peer of a distributed ledger, causes the second peer to perform operations for providing trusted execution of a smart contract that uses private data accessible to the second peer but not accessible to a first peer of the distributed ledger, the operations comprising:

• receiving a request to execute the smart contract, a proving key, and an identifier of a subroutine of the smart contract for which proof of computation is requested, wherein the subroutine uses the private data;
• beginning execution of the smart contract;
• detecting, during the execution of the smart contract, the subroutine;
• obtaining a program adapted for a zero-knowledge proving scheme that was generated based on the subroutine, wherein the program adapted for the zero-knowledge proving scheme includes logic to verify that the private data corresponds to manipulation detection codes of the private data;
• executing the subroutine;
• generating a zero-knowledge proof of computation of the subroutine using the zero-knowledge proving scheme based on the program adapted for the zero-knowledge proving scheme, a public input to the program adapted for the zero-knowledge proving scheme, a private input to the program adapted for the zero-knowledge proving scheme, and the proving key;
• resuming the execution of the smart contract after the subroutine to generate a full execution result of the smart contract;
• providing, to the first peer, the zero-knowledge proof and the public input;
• and
• providing the full execution result to a consensus mechanism of the distributed ledger.