Required JSON format:

{
  "version": 1,
  "tx": "hex_string",
  "inputs": [{
    "asset": "asset_id",
    "asset_blinder": "hex_string",
    "satoshi": number,
    "blind_value_proof": "hex_string"
  }],
  "outputs": [{
    "asset": "asset_id",
    "asset_blinder": "hex_string",
    "satoshi": number,
    "blind_value_proof": "hex_string"
  }],
  "scalars": ["hex_string"]
}