👋 Hi, I'm @nicfab

• 👀 I'm interested in AI, Privacy, Data Protection, Cybersecurity, and computer science.
• 🌱 I would like to spend more time learning what interests me... and it's so much stuff...

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🧑🏼‍💼 To know something about me:	🧑🏼‍💼 Qualcosa su di me:
EN About me	IT Chi sono

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📫 How to reach me and see my social profiles:

• EN:
  • links
  • How to contact me
• IT:
  • links
  • Come contattarmi

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🔐 My Web Key Directory (WKD)

As I wrote in my article entitled "Digital identity: Web Key Directory as a possible solution", I decided to set up my own Web Key Directory (WKD) to provide more security and to make it easier to identify the public keys of my email addresses.

📚 What is WKD?

Web Key Directory is a decentralized OpenPGP key discovery protocol that enables automatic public key retrieval using just an email address. Unlike traditional keyservers:

• 🔒 Domain-controlled: Key owners maintain full control
• 🌐 HTTPS-based: Leverages existing web infrastructure
• 🤖 Automatic: No manual key exchange required
• 🔐 Privacy-preserving: No central database of keys

🏗️ My Implementation

I'm running the Advanced WKD method across multiple domains with the following architecture:

Technical Stack

┌─────────────────┐
│   Email Client  │
└────────┬────────┘
         │ WKD Request
         ▼
┌─────────────────┐
│  DNS Resolution │
└────────┬────────┘
         │ HTTPS
         ▼
┌─────────────────┐
│  Nginx Server   │
│  ├─ TLS 1.3     │
│  ├─ CORS Headers│
│  └─ HSTS        │
└────────┬────────┘
         │
         ▼
┌─────────────────┐
│ WKD Directory   │
│ .well-known/    │
│  └─openpgpkey/  │
│    └─domain/    │
│      ├─hu/      │
│      └─policy   │
└─────────────────┘

Security Features

Feature	Implementation	Purpose
TLS 1.3	✅ Enforced	Modern encryption
HSTS	✅ max-age=63072000	Prevent downgrade attacks
CORS	✅ Configured	Web tool compatibility
CSP	✅ Restrictive	XSS protection
X-Frame-Options	✅ DENY	Clickjacking prevention

Performance Optimizations

• HTTP/2 enabled for multiplexing
• Brotli compression for reduced bandwidth
• OCSP stapling for faster TLS handshakes
• Static file serving with nginx caching

🔍 Verifying My WKD

Online Verification Tools

Check my WKD implementation status:

Tool	Provider	Features
WKD Checker	Miarecki	Both methods
DP42 Checker	DP42	Advanced debugging

Note: Metacode WKD Checker was discontinued on 1.05.2024

Command Line Verification

# Test WKD discovery
gpg --locate-external-keys "user at domain dot tld"

# Force WKD if disabled in config
gpg --auto-key-locate clear,wkd --locate-external-keys "user at domain dot tld"

# Debug WKD lookup
gpg --debug-level guru --locate-external-keys "user at domain dot tld" 2>&1 | grep wkd

🔑 Fetching My OpenPGP Keys

Method 1: Automatic GPG Discovery

Replace placeholders with actual values:

# Standard fetch
gpg --locate-external-keys "nicola at myGitHubUsername dot eu"

# With explicit WKD
gpg --auto-key-locate clear,wkd --locate-external-keys "nicola at myGitHubUsername dot eu"

Method 2: Direct HTTPS Download

Use the WKD checker tools to obtain the direct URL, then:

# Using curl with TLS 1.3
curl --tlsv1.3 -o publickey.asc "[URL-from-WKD-checker]"

# Using wget with security options
wget --secure-protocol=TLSv1_3 --max-redirect=0 -O publickey.asc "[URL-from-WKD-checker]"

# Verify the downloaded key
gpg --show-keys publickey.asc

Method 3: GitHub Integration

# Direct from GitHub
curl https://github.com/nicfab.gpg | gpg --import

# Or using GitHub API
curl https://api.github.com/users/nicfab/gpg_keys | jq -r '.[0].raw_key' | gpg --import

📱 Client Compatibility

Native WKD Support

Client	Platform	Version	Auto-discovery
Thunderbird	Cross-platform	78+	✅ Automatic
Evolution	Linux	3.36+	✅ Automatic
KMail	Linux/KDE	5.2+	✅ Automatic
Mutt	Unix-like	2.0+	✅ With GPG
ProtonMail Bridge	Desktop	2.0+	✅ On send
GPG Suite	macOS	2020.2+	✅ Full
Gpg4win	Windows	3.1.12+	✅ Full
Claws Mail	Cross-platform	3.17+	✅ With plugin

Mobile Support

• K-9 Mail (Android) - Via OpenKeychain
• FairEmail (Android) - Built-in support
• Canary Mail (iOS) - Premium feature

🛠️ Technical Deep Dive

WKD Hash Generation

The WKD protocol uses z-base32 encoded SHA-1 hashes:

# Python implementation example
import hashlib
import base64

def generate_wkd_hash(local_part):
    """Generate WKD hash from email local part"""
    # SHA-1 hash of the lowercase local part
    sha1 = hashlib.sha1(local_part.lower().encode()).digest()
    # Z-base32 encoding (simplified example)
    # Actual implementation requires proper z-base32
    return base64.b32encode(sha1).decode().lower()[:32]

Advanced vs Direct Method

graph LR
    A[Email Client] --> B{WKD Method?}
    B -->|Direct| C[openpgpkey.domain.tld]
    B -->|Advanced| D[openpgpkey.domain.tld/domain.tld]
    C --> E[/.well-known/openpgpkey/hu/]
    D --> F[/.well-known/openpgpkey/domain.tld/hu/]

Loading

DNS Requirements

; Advanced method (recommended)
openpgpkey.example.com. IN A     203.0.113.1
openpgpkey.example.com. IN AAAA  2001:db8::1

; Direct method alternative
_openpgpkey.example.com. IN TXT "v=wkd1"

Nginx Configuration Snippet

# WKD-specific location block
location /.well-known/openpgpkey/ {
    default_type "application/octet-stream";
    
    # Security headers
    add_header X-Content-Type-Options nosniff always;
    
    # CORS for web-based tools
    add_header 'Access-Control-Allow-Origin' '*' always;
    add_header 'Access-Control-Allow-Methods' 'GET, OPTIONS' always;
    
    # Cache control
    add_header Cache-Control "public, max-age=7200";
    
    # Disable directory listing
    autoindex off;
}

🔒 Security Considerations

Threat Model

Threat	Mitigation	Status
Key substitution	HTTPS + HSTS	✅ Protected
Enumeration attacks	Rate limiting	⚠️ Consider implementing
DNS hijacking	DNSSEC	⚠️ Domain-dependent
Privacy leaks	No logging of queries	✅ Configured
DDoS attacks	CDN consideration	📝 Future enhancement

Operational Security

• 🔑 Key rotation: Annual review recommended
• 📊 Monitoring: Log analysis for anomalies
• 🔄 Backup: Offline key backup mandatory
• 🛡️ Signing keys: Keep offline when possible

📈 Future Enhancements

• Implement rate limiting for enumeration protection
• Add DNSSEC for DNS integrity
• Consider CDN for global availability
• Automate key rotation workflow
• Add monitoring dashboard
• Implement backup WKD server

🔐 Keyoxide Integration

My WKD setup integrates seamlessly with Keyoxide, a decentralized identity verification platform. This creates a cryptographically verifiable digital identity that proves:

• ✅ I control the email addresses
• ✅ I own the associated domain names
• ✅ I manage the linked social accounts
• ✅ All without any central authority

Why This Matters

In an era of deepfakes, phishing, and identity theft, cryptographic proof of identity is crucial. The combination of:

• WKD: Proves domain control
• OpenPGP: Provides cryptographic signatures
• Keyoxide: Verifies cross-platform identity

Creates an unforgeable chain of trust that definitively answers: "Is this really the person they claim to be?"

Verify My Identity

You can verify my complete digital identity through Keyoxide:

• Profile accessible at: keyoxide.org/[email-address]
• All proofs cryptographically linked to my OpenPGP keys
• No registration or central database required

This isn't just about technology - it's about digital sovereignty and taking control of our online identities in a decentralized, privacy-respecting way.

🔐 Keyoxide Integration: Verifiable Digital Identity

My WKD setup integrates seamlessly with Keyoxide, a decentralized identity verification platform. This creates a cryptographically verifiable digital identity.

Why This Matters

In an era of deepfakes, phishing, and identity theft, cryptographic proof of identity is crucial. The combination of:

• WKD: Proves domain control through HTTPS
• OpenPGP: Provides unforgeable cryptographic signatures
• Keyoxide: Verifies cross-platform identity ownership

Creates an unbreakable chain of trust that definitively answers: "Is this really the person they claim to be?"

How It Works

Email Address → WKD → OpenPGP Key → Keyoxide → Verified Identity
     ↓           ↓          ↓           ↓            ↓
"claimed"   "domain    "crypto    "identity    "proven
            control"   signature"  proofs"      authentic"

Verify My Identity

You can verify my complete digital identity through Keyoxide:

• Profile accessible at: keyoxide.org/[email-address]
• All proofs cryptographically linked to my OpenPGP keys
• No registration or central database required

Identity Proofs

Keyoxide can verify ownership of:

• GitHub/GitLab/Codeberg repositories
• Mastodon and Fediverse accounts
• Personal websites via DNS records
• Social media profiles
• Professional platforms
• And many more...

Each proof is cryptographically signed and impossible to forge.

The Bigger Picture

This isn't just about technology - it's about:

• Digital Sovereignty: You control your identity
• Decentralization: No single point of failure
• Privacy: No tracking or data collection
• Trust: Mathematical proof, not corporate verification

In a world where anyone can claim to be anyone online, WKD + Keyoxide provides the solution: cryptographic certainty.

🎓 Learning Resources

Specifications

• Draft RFC: OpenPGP Web Key Directory
• GnuPG WKD Wiki
• Keyoxide Documentation

Implementation Guides

• My detailed article on WKD
• WKD Hosting Best Practices
• Email Security with WKD

Related Technologies

• OpenPGP - The encryption standard
• Autocrypt - Automated encryption
• DANE - DNS-based authentication

💡 Tips for Implementing Your Own WKD

1. Start with Advanced method - More flexible for subdomains
2. Test locally first - Use python -m http.server for testing
3. Validate CORS headers - Essential for web tools
4. Monitor access logs - Watch for enumeration attempts
5. Document everything - Future you will thank you

🤝 Contributing

Found an issue or have suggestions? Feel free to:

• Open an issue on my repositories
• Contact me through the links above
• Share your WKD implementation experiences

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🙏 Credits

• duxsco - For invaluable WKD implementation insights
• Jonatan Miarecki - For maintaining the excellent WKD checker tool
• GnuPG Team - For creating and maintaining the WKD specification
• Keyoxide Project - For promoting decentralized identity verification

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📊 Stats

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🔄 Last updated: September 2025
🛡️ Security: HTTPS-only with TLS 1.3
🔑 Implementation: Advanced WKD method
📧 Privacy: No direct email exposure