diff --git a/.github/WORKFLOW_SECURITY.md b/.github/WORKFLOW_SECURITY.md
new file mode 100644
index 000000000000..bf84eb0f1bef
--- /dev/null
+++ b/.github/WORKFLOW_SECURITY.md
@@ -0,0 +1,220 @@
+# GitHub Actions Workflow Security Guide
+
+## Overview
+
+This document describes the security practices implemented in the GitHub Actions workflows for this repository to protect private data and sensitive information.
+
+## Security Measures Implemented
+
+### 1. API Key Protection
+
+**Location**: `.github/workflows/etherscan-apiv2.yml`
+
+**Measures**:
+- ✅ API keys are constructed in subshells with command echoing disabled (`set +x`)
+- ✅ Secrets are masked using `::add-mask::` command at the start of jobs
+- ✅ Shell debugging is explicitly disabled to prevent command echoing
+- ✅ All API requests use HTTPS
+- ✅ Temporary files are cleaned up immediately after use
+- ✅ URL construction happens in isolated subshells to minimize exposure risk
+
+**Why**: While Etherscan requires API keys as URL parameters (not headers), we can still protect them by:
+1. Constructing URLs in subshells with `set +x` to disable command echoing
+2. Masking secrets at the job level using `::add-mask::`
+3. Avoiding storage of URLs containing secrets in environment variables that could be logged
+
+### 2. GitHub Actions Runtime Token Protection
+
+**Location**: `.github/actions/configure-docker/action.yml`
+
+**Measures**:
+- ✅ `ACTIONS_RUNTIME_TOKEN` is explicitly masked using `core.setSecret()`
+- ✅ Token is only exported for Docker buildkit cache operations
+- ✅ Token is scoped to workflow run and expires automatically
+
+**Why**: The runtime token is sensitive and should not appear in logs, even though it's automatically scoped and expires.
+
+### 3. Git Credential Management
+
+**Location**: `.github/workflows/self-hosted-runner-setup.yml`
+
+**Measures**:
+- ✅ Git credentials are cleared after each workflow run
+- ✅ Credential helpers are explicitly unset
+- ✅ No persistent credential storage
+
+**Why**: Self-hosted runners may persist data between runs, so credentials must be explicitly cleared.
+
+### 4. Secret Scanning
+
+**Locations**:
+- `.github/workflows/bitcoin-ownership-announcement.yml` (lines 248-294)
+- `.github/workflows/wiki-management.yml` (lines 47-83)
+- `.github/workflows/deploy-website.yml` (lines 81-105)
+
+**Measures**:
+- ✅ Automated scanning for common secret patterns
+- ✅ Pattern matching for private keys, passwords, API keys
+- ✅ Validation fails if potential secrets are detected
+- ✅ Third-party security scanning tools (TruffleHog, Trivy)
+
+**Why**: Multiple layers of defense prevent accidental secret commits.
+
+### 5. Environment Variable Sanitization
+
+**Location**: `.github/workflows/self-hosted-runner-setup.yml` (line 139)
+
+**Measures**:
+- ✅ Only safe environment variables are displayed
+- ✅ Variables containing tokens, secrets, passwords are filtered out
+- ✅ Explicit allow-list approach for environment display
+
+**Why**: Environment variables may contain sensitive data and should not be dumped to logs.
+
+### 6. Checkout Security
+
+**Locations**: Multiple workflows
+
+**Measures**:
+- ✅ `persist-credentials: false` used in sensitive operations
+- ✅ Clean checkouts to prevent cross-contamination
+- ✅ Limited token scopes where possible
+
+**Why**: Persisting credentials can lead to accidental exposure in subsequent steps.
+
+### 7. Workspace Cleanup
+
+**Location**: `.github/workflows/self-hosted-runner-setup.yml` (lines 142-152, 191-198)
+
+**Measures**:
+- ✅ Temporary files are removed after each run
+- ✅ Private keys (`.pem`, `.key`) are explicitly deleted
+- ✅ Environment files (`.env*`) are removed
+- ✅ Git credential files are cleared
+
+**Why**: Self-hosted runners persist data, so cleanup is essential to prevent data leakage.
+
+## Secret Types Protected
+
+### Never Logged or Exposed:
+1. **API Keys** (Etherscan, etc.)
+2. **GitHub Tokens** (GITHUB_TOKEN, ACTIONS_RUNTIME_TOKEN)
+3. **Private Keys** (SSH, GPG, cryptocurrency)
+4. **Passwords and Credentials**
+5. **Seed Phrases and Mnemonics**
+6. **Personal Access Tokens**
+
+### Public Data (Safe to Log):
+1. **ENS Names** (e.g., kushmanmb.eth)
+2. **Public Blockchain Addresses** (after resolution)
+3. **Repository Information** (commit SHAs, branch names)
+4. **Workflow Run IDs**
+5. **Public Configuration Values**
+
+## Best Practices for Contributors
+
+### When Adding New Workflows:
+
+1. **Prefer** header-based authentication when the API supports it
+   ```yaml
+   # ✅ BEST (if API supports it)
+   curl -H "Authorization: Bearer ${{ secrets.API_KEY }}" "https://api.example.com/data"
+   
+   # ✅ ACCEPTABLE (if API requires URL parameters)
+   # Use subshell with disabled echoing
+   (
+     set +x 2>/dev/null
+     curl "https://api.example.com/data?apikey=${{ secrets.API_KEY }}" -o output.json
+   )
+   
+   # ❌ BAD - Direct construction that could be logged
+   curl "https://api.example.com/data?apikey=${{ secrets.API_KEY }}"
+   ```
+
+2. **Always** mask secrets at the start of jobs
+   ```yaml
+   - name: Security - Mask secrets
+     run: |
+       set +x  # Disable shell debugging
+       echo "::add-mask::${{ secrets.MY_SECRET }}"
+   ```
+
+3. **Never** echo or log secrets
+   ```yaml
+   # ❌ BAD
+   - run: echo "API Key is ${{ secrets.API_KEY }}"
+   
+   # ✅ GOOD
+   - run: echo "API Key configured successfully"
+   ```
+
+4. **Use** subshells for API calls that require secrets in URLs
+   ```bash
+   # ✅ GOOD - Subshell with disabled echoing
+   (
+     set +x 2>/dev/null  # Disable debugging
+     curl "https://api.example.com/data?apikey=${{ secrets.API_KEY }}" -o output.json
+   )
+   ```
+
+5. **Disable** shell debugging in sensitive operations
+   ```bash
+   set +x  # Disable debugging
+   # sensitive operations here
+   ```
+
+6. **Clear** credentials and temporary files after use
+   ```bash
+   git config --unset-all credential.helper
+   rm -rf .git/credentials
+   ```
+
+7. **Use** `persist-credentials: false` when checking out code
+   ```yaml
+   - uses: actions/checkout@v6
+     with:
+       persist-credentials: false
+   ```
+
+### When Reviewing Pull Requests:
+
+1. Check for hardcoded secrets or credentials
+2. Verify API keys are passed via headers, not URLs
+3. Ensure shell debugging is disabled for sensitive operations
+4. Confirm credentials are cleared after use
+5. Look for accidental secret logging (`echo`, `print`, etc.)
+
+## Security Checklist for New Workflows
+
+- [ ] Secrets are passed via HTTP headers, not URL parameters
+- [ ] Secrets are masked using `::add-mask::` at job start
+- [ ] Shell debugging is disabled (`set +x`)
+- [ ] No secrets are echoed or logged
+- [ ] Git credentials are cleared after use (if applicable)
+- [ ] `persist-credentials: false` is used for checkout (if applicable)
+- [ ] Workspace is cleaned up after job completion (for self-hosted)
+- [ ] Security scanning is included (if handling user content)
+- [ ] Timeouts are set to prevent runaway jobs
+
+## Reporting Security Issues
+
+If you discover a security vulnerability in our workflows:
+
+1. **Do NOT** open a public issue
+2. Follow the process in [SECURITY.md](../SECURITY.md)
+3. Include details about the vulnerability
+4. Suggest a fix if possible
+
+## References
+
+- [GitHub Actions Security Best Practices](https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions)
+- [Using Secrets in GitHub Actions](https://docs.github.com/en/actions/security-guides/using-secrets-in-github-actions)
+- [Security Hardening for Self-Hosted Runners](https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions#hardening-for-self-hosted-runners)
+
+## Last Updated
+
+This document was last updated: 2026-02-15
+
+---
+
+**Note**: This is a living document. As new security measures are implemented or best practices evolve, this document will be updated accordingly.
diff --git a/.github/actions/configure-docker/action.yml b/.github/actions/configure-docker/action.yml
index 5c9531d35925..7ffd2508780f 100644
--- a/.github/actions/configure-docker/action.yml
+++ b/.github/actions/configure-docker/action.yml
@@ -1,5 +1,7 @@
 name: 'Configure Docker'
 description: 'Set up Docker build driver and configure build cache args'
+# Security: This action handles GitHub Actions cache tokens (ACTIONS_RUNTIME_TOKEN)
+# which are automatically masked to prevent exposure in logs.
 inputs:
   cache-provider:
     description: 'gha or cirrus cache provider'
@@ -28,6 +30,10 @@ runs:
         script: |
           Object.keys(process.env).forEach(function (key) {
             if (key.startsWith('ACTIONS_')) {
+              // Security: Mask the runtime token to prevent accidental exposure in logs
+              if (key === 'ACTIONS_RUNTIME_TOKEN') {
+                core.setSecret(process.env[key]);
+              }
               core.info(`Exporting ${key}`);
               core.exportVariable(key, process.env[key]);
             }
diff --git a/.github/workflows/etherscan-apiv2.yml b/.github/workflows/etherscan-apiv2.yml
index 9d8a3fa8f2f9..34db9369ede6 100644
--- a/.github/workflows/etherscan-apiv2.yml
+++ b/.github/workflows/etherscan-apiv2.yml
@@ -15,6 +15,16 @@
 # This workflow is part of the kushmanmb-org/bitcoin repository
 # and is maintained by the repository owner and authorized contributors.
 # ═══════════════════════════════════════════════════════════════════
+#
+# SECURITY NOTICE:
+# This workflow handles sensitive API keys and follows security best practices:
+# - API keys are constructed in subshells with command echoing disabled (set +x)
+# - Secrets are masked using GitHub Actions ::add-mask:: command
+# - Shell debugging (set -x) is explicitly disabled at job start
+# - All API requests use HTTPS
+# - No sensitive data is logged or exposed in workflow outputs
+# - Temporary files with API responses are cleaned up immediately
+# ═══════════════════════════════════════════════════════════════════
 
 name: Etherscan API Integration (kushmanmb.eth)
 
@@ -67,6 +77,16 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
           fetch-depth: 0
 
+      - name: Security - Disable shell debugging and mask secrets
+        run: |
+          # Ensure shell debugging is disabled to prevent secret exposure
+          set +x
+          # Mask API key if accidentally echoed (additional protection)
+          if [ -n "${{ secrets.ETHERSCAN_API_KEY }}" ]; then
+            echo "::add-mask::${{ secrets.ETHERSCAN_API_KEY }}"
+          fi
+          echo "✓ Security measures applied"
+
       - name: Setup environment
         run: |
           echo "WORKFLOW_RUN_TIME=$(date -u +%Y-%m-%d-%H-%M-%S)" >> $GITHUB_ENV
@@ -104,11 +124,18 @@ jobs:
           # Use Etherscan API to resolve ENS name
           echo "Attempting ENS resolution via Etherscan API V2..."
           
-          # Use Etherscan's ENS lookup API V2 with error handling
-          ENS_LOOKUP_URL="https://api.etherscan.io/v2/api?chainid=1&module=ens&action=getaddress&name=${ENS_NAME}&apikey=${{ secrets.ETHERSCAN_API_KEY }}"
+          # Security: Build the URL carefully to prevent API key exposure
+          # Etherscan requires apikey as URL parameter, so we must prevent logging
+          # Use set +x and build URL in a subshell to minimize exposure risk
+          (
+            set +x 2>/dev/null  # Disable command echoing
+            ENS_LOOKUP_URL="https://api.etherscan.io/v2/api?chainid=1&module=ens&action=getaddress&name=${ENS_NAME}&apikey=${{ secrets.ETHERSCAN_API_KEY }}"
+            
+            # Fetch with error handling - URL construction happens in subshell
+            curl -s -f "${ENS_LOOKUP_URL}" -o /tmp/ens_response.json
+          )
           
-          # Fetch with error handling
-          if ! API_RESPONSE=$(curl -s -f "${ENS_LOOKUP_URL}"); then
+          if [ ! -f /tmp/ens_response.json ]; then
             echo "⚠️ Failed to connect to Etherscan API"
             echo "ENS_NAME=${ENS_NAME}" >> $GITHUB_ENV
             echo "ENS_RESOLVED=false" >> $GITHUB_ENV
@@ -117,6 +144,8 @@ jobs:
           fi
           
           # Extract address with error handling
+          API_RESPONSE=$(cat /tmp/ens_response.json)
+          rm -f /tmp/ens_response.json
           RESOLVED_ADDRESS=$(echo "$API_RESPONSE" | jq -r '.result // empty' 2>/dev/null || echo "")
           
           # Check if we got a valid address (simplified condition)
@@ -229,10 +258,13 @@ jobs:
           # Build API URL - All endpoints now use V2 API
           api_url="${BASE_URL}?chainid=1&module=${MODULE}&action=${ACTION}${PARAMS}"
 
-          # Make request with API key from secret
-          # Key is only exposed during curl execution, not in logs
-          curl -s "${api_url}&apikey=${{ secrets.ETHERSCAN_API_KEY }}" \
-            -o data/etherscan/latest.json || {
+          # Security: Make request with API key as URL parameter (Etherscan requirement)
+          # Use subshell with disabled command echoing to prevent API key logging
+          (
+            set +x 2>/dev/null  # Disable command echoing
+            full_url="${api_url}&apikey=${{ secrets.ETHERSCAN_API_KEY }}"
+            curl -s "${full_url}" -o data/etherscan/latest.json
+          ) || {
             echo '{"status":"0","message":"API request failed"}' \
               > data/etherscan/latest.json
           }