implementing-log-integrity-with-blockchain

name	implementing-log-integrity-with-blockchain
description	Build an append-only log integrity chain using SHA-256 hash chaining for tamper detection. Each log entry is hashed with the previous entry's hash to create a blockchain-like structure where modifying any entry invalidates all subsequent hashes. Implements log ingestion, chain verification, tamper detection with pinpoint identification, and periodic checkpoint anchoring to external timestamping services.
domain	cybersecurity
subdomain	security-operations
tags	["implementing","log","integrity","with"]
version	1.0
author	mahipal
license	Apache-2.0

Instructions

1. Install dependencies: pip install requests
2. Ingest log entries from syslog, JSON, or plain text files.
3. For each entry, compute SHA-256 hash of: previous_hash + timestamp + log_content.
4. Store the chain as a JSON ledger with entry index, timestamp, content hash, previous hash, and chain hash.
5. Verify chain integrity by recomputing all hashes and detecting breaks.
6. Optionally anchor checkpoint hashes to an external timestamping service.

python scripts/agent.py --log-file /var/log/syslog --chain-file log_chain.json --verify --output integrity_report.json

Examples

Chain Entry Structure

{"index": 42, "timestamp": "2024-01-15T10:30:00Z", "content_hash": "a1b2c3...",
 "prev_hash": "d4e5f6...", "chain_hash": "SHA256(prev_hash + timestamp + content_hash)"}

Tamper Detection

If entry 42 is modified, chain_hash[42] will not match SHA256(chain_hash[41] + ...), and all entries from 42 onward will be flagged as invalid.