T09 · Insecure Skill Coding Practices
Error
- Location
server.py:217- Finding
Validation Can Falsely Certify Blockchain Recoverability Using a Local Ciphertext Cache
- Content
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str: from algosdk.transaction import PaymentTxn sp = client.suggested_params() txn = PaymentTxn(sender=sender, sp=sp, receiver=sender, amt=0, note=note) return client.send_transaction(txn.sign(sk)) # ── Note fetch (shared by validate + recover) ───────────────────────────────── def _get_note(row: dict, idx=None) -> str: """Fetch note from blockchain (preferred) or local note_b64 cache (fallback).""" txid = row.get("txid") if txid: try: client = idx if idx is not None else _indexer() tx = client.transaction(txid) note = tx.get("transaction", {}).get("note") if note: return note except Exception: pass note_local = row.get("note_b64") if note_local: return note_local raise ValueError(f"No note available for txid={txid!r}") ``` The single-transaction anchoring path immediately records the locally generated ciphertext after submission: ```python enc = _encrypt(single_bytes, note_key) if len(enc) > 1024: raise RuntimeError(f"Encrypted note {len(enc)} > 1024 bytes — reduce payload") txid = _send_tx(client, addr, sk, enc) _append_jsonl(anchors_path, { "ts": now_ts, "date": date_key, "txid": txid, "ledger_tip": ledger_tip, "entries": entries, "root_hash": base_meta["root_hash"], "content_hash": content_hash, "multi_tx": False, "note_b64": base64.b64encode(enc).decode("ascii"), "status": "anchored", }) ``` The same behavior occurs for every part of a multi-transaction anchor: ```python enc = _encrypt(payload_bytes, not ...[truncated 3556 chars]- Remediation
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