src/pqc_audit_log_fs/anchor.py
| 1 | """MerkleAnchor - periodically publish segment roots to an external transparency log.""" |
| 2 | |
| 3 | from __future__ import annotations |
| 4 | |
| 5 | from abc import ABC, abstractmethod |
| 6 | from dataclasses import dataclass, field |
| 7 | |
| 8 | |
| 9 | class AnchorSink(ABC): |
| 10 | """Where anchored roots get published (blockchain, transparency log, etc.).""" |
| 11 | |
| 12 | @abstractmethod |
| 13 | def publish(self, log_id: str, segment_number: int, merkle_root: str) -> str: |
| 14 | """Return an opaque receipt/transaction ID.""" |
| 15 | |
| 16 | |
| 17 | class NullAnchorSink(AnchorSink): |
| 18 | """No-op sink - useful for tests.""" |
| 19 | |
| 20 | def __init__(self) -> None: |
| 21 | self.received: list[tuple[str, int, str]] = [] |
| 22 | |
| 23 | def publish(self, log_id: str, segment_number: int, merkle_root: str) -> str: |
| 24 | self.received.append((log_id, segment_number, merkle_root)) |
| 25 | return f"null-receipt-{segment_number}" |
| 26 | |
| 27 | |
| 28 | @dataclass |
| 29 | class MerkleAnchor: |
| 30 | """Periodic anchoring of segment roots to an external store.""" |
| 31 | |
| 32 | sink: AnchorSink |
| 33 | published: dict[int, str] = field(default_factory=dict) |
| 34 | |
| 35 | def anchor_segment( |
| 36 | self, log_id: str, segment_number: int, merkle_root: str |
| 37 | ) -> str: |
| 38 | receipt = self.sink.publish(log_id, segment_number, merkle_root) |
| 39 | self.published[segment_number] = receipt |
| 40 | return receipt |
| 41 | |