Validation system and validation method for byzantine fault detection

A validation method executed by a computer outside a first computer system, comprising:

• storing transaction management data for each transaction executed in the first computer system in a second computer system;
• the first computer system managing an object group set, the object group set being an object group for each target, the object group being one or more objects, and the object being data indicating a state of the target;
• the first computer system being configured, when a transaction is executed in response to a transaction request, which is a transaction request for reading and/or writing an object indicating a state of a target, to return a transaction result, which is data related to a result of the transaction, and the transaction result including a proof related to the execution of the transaction;
• for each transaction, the proof including a main key and a version of a read object read in the execution of the transaction and a main key and a version of a written object written in the execution of the transaction, and a state indicated by the written object or a summary thereof;
• for each transaction, the transaction management data including data held by a transaction request of the transaction and data which can be acquired from the transaction result of the transaction and includes a main key and a version of a read object read in execution of the transaction, a main key and a version of a written object written in the execution of the transaction, and a state indicated by the written object or a summary thereof;
• executing input/output validation in response to a validation request;
• in the input/output validation,
• specifying transaction management data of a validation target transaction from the second computer system;
• for each written object specified from the transaction management data,
• specifying all the read objects having been read for writing of the written object from the transaction management data;
• and
• determining whether a state output by executing a definitive function, which is equal to a definitive function used in the execution of the transaction in the first computer system or a summary thereof matches the state or the summary thereof specified from the transaction management data.

A validation system, comprising:

• a storage part;
• and
• a validation part, wherein
• the storage part stores in a second computer system transaction management data for each transaction executed in a first computer system;
• the first computer system manages an object group set, the object group set is an object group for each target, the object group is one or more objects, and the object is data indicating a state of the target;
• the first computer system is configured, when a transaction is executed in response to a transaction request, which is a transaction request for reading and/or writing an object indicating a state of a target, to return a transaction result, which is data related to a result of the transaction, and the transaction result includes a proof related to the execution of the transaction;
• for each transaction, the proof includes a main key and a version of a read object read in the execution of the transaction and a main key and a version of a written object written in the execution of the transaction, and a state indicated by the written object or a summary thereof;
• for each transaction, the transaction management data includes data held by a transaction request of the transaction and includes data acquired from the transaction result of the transaction, a main key and a version of a read object read in the execution of the transaction, a main key and a version of a written object written in the execution of the transaction, and a state indicated by the written object or a summary thereof;
• the validation part executes input/output validation in response to a validation request;
• in the input/output validation, the validation part
• specifies transaction management data of a validation target transaction from the second computer system;
• for each written object specified from the transaction management data,
• specifies all the read objects having been read for writing of the written object from the transaction management data;
• and
• determines whether a state output by executing a definitive function, which is equal to a definitive function used in the execution of the transaction in the first computer system or a summary thereof matches the state or the summary thereof specified from the transaction management data.