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+# Lab 3 — Secure Git Submission
+
+## Task 1 — SSH Commit Signature Verification
+
+### 1.1 Benefits of Signing Commits
+
+SSH commit signing provides several critical security benefits:
+
+- **Authenticity** — verifies that the commit was actually made by the claimed author, not someone who spoofed `user.name` and `user.email`
+- **Integrity** — guarantees that the commit content has not been modified after signing
+- **Non-repudiation** — the author cannot deny authorship of a signed commit
+- **Supply chain protection** — prevents injection of malicious code on behalf of trusted developers
+
+### 1.2 SSH Key Setup and Configuration
+
+Git configuration for commit signing:
+
+```bash
+git config --local gpg.format ssh
+git config --local user.signingkey ~/.ssh/id_ed25519.pub
+git config --local commit.gpgSign true
+```
+
+SSH key was added to GitHub as a **Signing Key**:
+
+![img_3.png](img_3.png)
+![img_4.png](img_4.png)
+
+### 1.3 Why is commit signing critical in DevSecOps workflows?
+
+In DevSecOps, commit signing is critical for several reasons:
+
+1. **CI/CD Pipeline Protection** — only verified commits from trusted developers can trigger production deployments
+2. **Audit Trail** — cryptographic proof of authorship for compliance and security audits
+3. **Account Compromise Protection** — even if an attacker gains access to a GitHub account, they cannot create verified commits without the private key
+4. **Branch Protection** — GitHub can be configured to require signed commits for merging into protected branches
+
+### 1.4 Verified Badge Evidence
+
+After pushing the signed commit, GitHub displays the "Verified" badge confirming SSH signature validity:
+
+![img_2.png](img_2.png)
+
+---
+
+## Task 2 — Pre-commit Secret Scanning
+
+### 2.1 Pre-commit Hook Setup
+
+Created `.git/hooks/pre-commit` file with a script that scans for secrets using TruffleHog and Gitleaks via Docker.
+
+```bash
+chmod +x .git/hooks/pre-commit
+```
+
+The hook performs the following:
+1. Collects list of staged files
+2. Excludes `lectures/` directory (educational content)
+3. Runs TruffleHog scan on non-lectures files
+4. Runs Gitleaks scan on each staged file
+5. Blocks commit if secrets are found in non-excluded files
+
+### 2.2 Secret Detection Test — Blocked Commit
+
+Tested with a potential secret in a markdown file. The pre-commit hook successfully detected the secret and blocked the commit:
+
+![img_1.png](img_1.png)
+
+### 2.3 Successful Commit After Removing Secret
+
+After removing the secret, the commit proceeded successfully:
+
+![img.png](img.png)
+
+### 2.4 How Automated Secret Scanning Prevents Security Incidents
+
+Automated secret scanning prevents security incidents through:
+
+1. **Shift-left Security** — issues are detected before reaching the repository, not after a leak
+2. **Human Error Mitigation** — developers may accidentally commit credentials; automation prevents this
+3. **Mandatory Enforcement** — pre-commit hooks run automatically on every commit attempt
+4. **Multi-detector Coverage** — TruffleHog and Gitleaks use different detection patterns, increasing coverage
+5. **Cost Reduction** — rotating compromised keys and incident investigation is significantly more expensive than prevention
+
+---
+
+## Summary
+
+| Task | Status |
+|------|--------|
+| SSH commit signing configuration | Done |
+| Verified badge on GitHub | Done |
+| Pre-commit hook with TruffleHog + Gitleaks | Done |
+| Secret detection testing | Done |