A Guide on How to Use Asset Proofs in Scalar DL

This document sets out some guidelines for using Asset Proofs in Scalar DL.

What is an Asset Proof in Scalar DL?

An Asset Proof in Scalar DL is a set of information about an asset record that is created along with the asset record. It is composed of the following items so that it can be treated as evidence of the creation of an asset record by a ledger.

  • The ID of an asset record
  • Age of the asset record
  • Nonce of the execution request that creates the asset record
  • A cryptographic hash of the asset record
  • The digital signature of the above four records

The Benefits of Asset Proofs

Since Asset Proofs are evidence at the time of execution by a ledger, it is hard for the leger to tamper data after the evidence is created because the proofs and the ledger states would be inconsistent. Thus, making use of Asset Proofs appropriately could reduce the risk of tampering of data, so it could make Scalar DL more tamper-evident without creating additional computational resources such as ordering components. However, the ledger can tamper data from the beginning and it makes the proofs insufficient to detect the tampering.

How to use Asset Proofs

You can get Asset Proofs from the result of the executeContract method of the SDKs. Please check the documents of client SDKs for more detail. A proof can be validated if it is not tampered and it is from the ledger by verifying the signature.

It is recommended to store the proofs outside of a domain in which the ledger is managed so that malicious activities in one domain can be detected by the other domain. It is worth considering storing proofs in cloud storages for ease of management.

The proofs obtained in execution can be utilized when you do validateLedger. validateLedger also returns the proof of a specified asset record after doing ledger-side validation. Then, the client can check if the proof it has is the same as the one returned from the ledger.