{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "title": "Blockchain Certificates Receipt Schema, Version 1.2",
  "id": "https://w3id.org/blockcerts/schema/1.2/blockchain-receipt-1.2.json",
  "description": "Provides evidence of the certificate on the blockchain, using the chainpoint v2 standard",
  "type": "object",
  "properties": {
    "@context": {
      "type": "string",
      "pattern": "https://w3id.org/chainpoint/v2",
      "description": "This should always be chainpoint v2 JSON LD context"
    },
    "type": {
      "type": "string",
      "pattern": "ChainpointSHA256v2",
      "description": "type of hash. Currently the only supported hash type is SHA256, with chainpoint type ChainpointSHA256v2."
    },
    "targetHash": {
      "type": "string",
      "pattern": "[A-Fa-f0-9]{64}",
      "description": "hash of item being verified. Currently the only supported hash type is SHA256, and the targetHash format is validated accordingly."
    },
    "merkleRoot": {
      "type": "string",
      "pattern": "[A-Fa-f0-9]{64}",
      "description": "Merkle root value -- this is anchored to the blockchain. Currently the only supported hash type is SHA256, and merkleRoot format is validated accordingly."
    },
    "proof": {
      "type": "array",
      "description": "how to walk the Merkle tree from the target item to the Merkle root",
      "items": {
        "type": "object",
        "properties": {
          "left": {
            "type": "string",
            "pattern": "[A-Fa-f0-9]{64}",
            "description": "value of left neighbor to combine into parent hash. Currently the only supported hash type is SHA256, and this value format is validated accordingly."
          },
          "right": {
            "type": "string",
            "pattern": "[A-Fa-f0-9]{64}",
            "description": "value of right neighbor to combine into parent hash. Currently the only supported hash type is SHA256, and this value format is validated accordingly."

          }
        }
      }
    },
    "anchors": {
      "type": "array",
      "description": "how the proof is anchored to the blockchain",
      "items": {
        "type": "object",
        "properties": {
          "type": {
            "type": "string",
            "pattern": "BTCOpReturn",
            "description": "type of anchor, e.g. BTCOpReturn. Currently the only supported value is BTCOpReturn."
          },
          "sourceId": {
            "type": "string",
            "pattern": "[A-Fa-f0-9]{64}",
            "description": "How to lookup the proof on the blockchain. Currently this is expected to be the (value of the) Bitcoin transaction id, and this value format is validated accordingly"

          }
        },
        "required": [
          "sourceId"
        ]
      }
    }
  },
  "required": [
    "@context",
    "targetHash",
    "merkleRoot",
    "proof",
    "anchors"
  ]
}