Anthropic-Cybersecurity-Skills/skills/implementing-log-integrity-with-blockchain/SKILL.md

name, description, domain, subdomain, tags, version, author, license

name	description	domain	subdomain	tags	version	author	license
implementing-log-integrity-with-blockchain	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.	cybersecurity	security-operations	implementing log integrity with	1.0	mahipal	Apache-2.0

Implementing Log Integrity with Blockchain

When to Use

• When deploying or configuring implementing log integrity with blockchain capabilities in your environment
• When establishing security controls aligned to compliance requirements
• When building or improving security architecture for this domain
• When conducting security assessments that require this implementation

Prerequisites

• Familiarity with security operations concepts and tools
• Access to a test or lab environment for safe execution
• Python 3.8+ with required dependencies installed
• Appropriate authorization for any testing activities

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.