The ledger data is based on the immutability and time-stamped feature of the blockchain technology. The ledger data services include Hash ledger and Raw data storage. The data consists of Key+Value.
- Hash ledger
The Hash ledger is to process raw data using a hashing calculation and upload it via Hash API. VeChain ToolChainTM will upload the data onto the blockchain. The Hash ledger adopts key-value, with key being VID, and the value being a 32-bytes-long hash value. All the VIDs on VeChain ToolChainTM are unique, and can be embedded within different devices such as NFC chips, QR codes or data VID.
There are two typical uses of Hash Ledger:
- Cost control: the hashed data will be limited to 32 bytes, which greatly reduces the use of blockchain storage space and reduces network costs;
- Data privacy: When you do not want to expose the original data to the end user, by the process of hashing, that is data compression (any content, even a punctuation mark, will have a different hash value) and no one can find the data pattern to reverse it. Therefore, when the hash value is stored on the blockchain, the end user can only see the hash value on the blockchain, and cannot infer the specific data content.
- Raw data storage:
Raw data storage: Customers store their raw data ("for example, Company A obtained ISO90001 certification") directly on the blockchain. The end user can directly view the original content of "Company A has obtained ISO90001 certification" on the interface, and the system will upload the requested data to the blockchain for deposit. The original text of the data is stored as key-value, with the key being the VID, and the value being a variable-length byte (its length is 0 ~ 10KB). All VIDs are unique on the VeChain ToolChainTM platform and can exist in different forms such as NFC chip VID, QR code VID, or data VID. The Raw data storage will consume 1TCC for every 32 bytes uploaded.
- Use case: Hash ledger and raw data storage fit the services of document storage, data storage and IP preservation.