Idea: Adding a checksum to verify the integrity of each record in the BIP-329 .jsonl file.

[xavierfiechter]

import json
import hashlib

def calculate_checksum(record):
    # Exclude the checksum field itself
    record_without_checksum = {k: v for k, v in record.items() if k != "checksum"}
    # Sort keys to ensure deterministic order
    serialized_record = json.dumps(record_without_checksum, sort_keys=True)
    # Compute SHA-256 hash
    return hashlib.sha256(serialized_record.encode('utf-8')).hexdigest()

# Example usage
record = { 
    "type": "output", 
    "ref": "f91d0a8a78462bc59398f2c5d7a84fcff491c26ba54c4833478b202796c8aafd:1", 
    "label": "Output", 
    "spendable": "false" 
}

# Add the checksum to the record
record["checksum"] = calculate_checksum(record)

# Simulate a change to the record
modified_record = { 
    "type": "output", 
    "ref": "f91d0a8a78462bc59398f2c5d7a84fcff491c26ba54c4833478b202796c8aafd:1", 
    "label": "Outp", # simulate truncated data 
    "spendable": "false" 
}

# Check if the modified record's checksum matches
is_changed = record.get("checksum") != calculate_checksum(modified_record)

print("Record has", "changed" if is_changed else "not changed")