Proof of Existence of a State/Data

State proof query

As mentioned in the Orion description here and detailed here, Orion maintains a separate persisted graph data structure for historical data transitions, so a user can execute queries on those historical changes to understand the lineage of each data item. For more explanations about provenance queries and the different views they provide on historical data, see Provenance queries.

In addition to the provenance graph store, Orion uses an Ethereum-style Merkle-Patricia Trie to provide cryptographically verifiable proofs of all state transitions. It provides only one single type of proof: that a specific key was associated with a specific value when a specific block was committed to the ledger.

For each block, a root of the Merkle-Particia Trie is stored inside the block header - state_merkle_tree_root_hash. And because of the tamper-proof nature of the ledger, the trie root is enough to prove the existence of a specific value at the time the block was committed.

Sign json serialized query

bin/signer -data '{"user_id":"alice","block_number":5,"db_name":"db2","key":"key1"}' -privatekey=deployment/sample/crypto/alice/alice.key

Signature

MEUCIElKzVqsY/4Yf1gf+3PCU0Su7KF8scdcTkRjZwQjjc0QAiEA/MbcF3XUzdfZkLIPI0jEayrqRwuC4bLLsqtzT5ArObc=

Submit query

curl \
     -H "Content-Type: application/json" \
     -H "UserID: alice" \
     -H "Signature: MEUCIElKzVqsY/4Yf1gf+3PCU0Su7KF8scdcTkRjZwQjjc0QAiEA/MbcF3XUzdfZkLIPI0jEayrqRwuC4bLLsqtzT5ArObc=" \
     -X GET -G "http://127.0.0.1:6001/ledger/proof/data/db2/key1?block=5" | jq .

Output

{
  "response": {
    "header": {
      "node_id": "bdb-node-1"
    },
    "path": [
      {
        "hashes": [
          "AgIKCw4KDAkAAw8PBAkDDAIGDQILCAMHCQ8MAgkGBAsHDwYKAwUKBgkJAA0JCAwICQYBCg4ICwIGDA0ODwI=",
          "y08re7h7i3RY2CTFDDiZB5HQUhTK0pJfB++VRIG204E="
        ]
      },
      {
        "hashes": [
          null,
          null,
          null,
          null,
          "DpE0Npt4BFM3vZsJzmG4PO1xlMYTpoA5U3nK10Vejsc=",
          "0U6UMnKLCuzIMOsosKa1mZjfqk/vU/Lfpxw2nBDfuFQ=",
          null,
          null,
          null,
          "ZHm1aGvKmHJFL5H9gEIGyo3sNK+m+0T5Y4W7RalD3rE=",
          null,
          null,
          null,
          null,
          null,
          null
        ]
      },
      {
        "hashes": [
          "U9PoJB+8o7P9M7EsbVfVxNd2sENGYlXqeviBYUxLvU0=",
          "oj5KCPc3GFzGJPHjfpnFagPpQ5la98LWreApQNc3ssw=",
          "ENQ9r2wqD202CibxAlru6z/xfdHouQeTQ3x+466a4ik=",
          "ni4p/R5zAdxjOje/0vTLhk0nKSDqe9SgLxmXc7Iw+BY=",
          null,
          null,
          "8IqfhFECCgEPd8uOYjNnfNULy4l3oOirqU4hhIQChDE=",
          null,
          null,
          null,
          null,
          "P/6M7PdrnB9aoxEx5MkVtTVCfrQeUoGoFPk/oyey+48=",
          null,
          null,
          "ZLxYv3o1wbGKjAYNlfU5wzvH1VqB6PO+TpbDgrSyhDo=",
          "hgbr1+op4LBUUXNn1paw14L0kuaOyOU5XgtvXbWebl8="
        ]
      }
    ]
  },
  "signature": "MEYCIQCxrMF5rZlsv/4CcICzcvdH/Xbn+C99Mqswuvdy3gLzegIhANla0V7MGrir9c/I5Q+dIzRDjMnS7GJgdcah0p8XgO1U"
}

The first element in the path is a ValueNode. For node types, see [here].