====== ACME integracija ======

<WRAP round info>
**Složenost:** Srednja \\
**Trajanje:** 1-2 sata postavljanja \\
**Preduvjet:** Pristup DNS/HTTP izazovu
</WRAP>

Integracija ACME protokola (RFC 8555) za automatsku obnovu certifikata s Post-Quantum podrškom.

----

===== Arhitektura =====

<mermaid>
sequenceDiagram
    participant Client as ACME klijent
    participant CA as ACME CA
    participant DNS as DNS/HTTP Server
    participant App as Aplikacija

    Client->>CA: 1. Stvaranje računa
    Client->>CA: 2. Stvaranje narudžbe (CSR)
    CA->>Client: 3. Izazov (DNS-01/HTTP-01)
    Client->>DNS: 4. Ispunjenje izazova
    CA->>DNS: 5. Validacija izazova
    CA->>Client: 6. Izdavanje certifikata
    Client->>App: 7. Deploy certifikata
    Client->>App: 8. Ponovno učitavanje servisa
</mermaid>

----

===== Instalacija Certbota =====

<code bash>
# Debian/Ubuntu
apt update && apt install certbot python3-certbot-nginx

# RHEL/CentOS
dnf install certbot python3-certbot-nginx

# S DNS pluginom (Cloudflare)
apt install python3-certbot-dns-cloudflare
</code>

----

===== HTTP-01 izazov =====

**Za javno dostupne web servere:**

<code bash>
# Nginx
certbot --nginx -d example.com -d www.example.com

# Apache
certbot --apache -d example.com -d www.example.com

# Samostalno (Port 80 slobodan)
certbot certonly --standalone -d example.com

# Webroot (postojeći server)
certbot certonly --webroot -w /var/www/html -d example.com
</code>

**Auto-Renewal Cron:**

<code bash>
# Automatski aktivirano pri instalaciji certbota
# Ručna provjera:
systemctl status certbot.timer

# Ručno testiranje
certbot renew --dry-run
</code>

----

===== DNS-01 izazov =====

**Za interne servere ili wildcards:**

==== Cloudflare ====

<code ini>
# /etc/letsencrypt/cloudflare.ini
dns_cloudflare_api_token = YOUR_API_TOKEN
</code>

<code bash>
chmod 600 /etc/letsencrypt/cloudflare.ini

certbot certonly \
    --dns-cloudflare \
    --dns-cloudflare-credentials /etc/letsencrypt/cloudflare.ini \
    -d example.com \
    -d "*.example.com"
</code>

==== Route53 (AWS) ====

<code bash>
# AWS vjerodajnice u ~/.aws/credentials
certbot certonly \
    --dns-route53 \
    -d example.com \
    -d "*.example.com"
</code>

==== Azure DNS ====

<code bash>
# S certbot-dns-azure pluginom
pip install certbot-dns-azure

certbot certonly \
    --authenticator dns-azure \
    --dns-azure-credentials /etc/letsencrypt/azure.ini \
    -d example.com
</code>

----

===== Deployment Hooks =====

Hooks se izvršavaju nakon uspješne obnove.

==== Nginx Reload ====

<code bash>
# /etc/letsencrypt/renewal-hooks/deploy/reload-nginx.sh
#!/bin/bash
systemctl reload nginx
echo "$(date): Nginx reloaded" >> /var/log/certbot-deploy.log
</code>

<code bash>
chmod +x /etc/letsencrypt/renewal-hooks/deploy/reload-nginx.sh
</code>

==== Apache Reload ====

<code bash>
# /etc/letsencrypt/renewal-hooks/deploy/reload-apache.sh
#!/bin/bash
systemctl reload apache2
</code>

==== Docker Container ====

<code bash>
# /etc/letsencrypt/renewal-hooks/deploy/docker-reload.sh
#!/bin/bash
docker exec nginx nginx -s reload
# ili
docker-compose restart nginx
</code>

==== Obavijest ====

<code bash>
# /etc/letsencrypt/renewal-hooks/post/notify.sh
#!/bin/bash
DOMAINS=$(echo $RENEWED_DOMAINS | tr ' ' '\n')
echo "Obnovljeno: $DOMAINS" | mail -s "Certifikat obnovljen" admin@example.com
</code>

----

===== Privatna ACME CA (Step-CA) =====

Za internu PKI s ACME podrškom:

<code bash>
# Instalacija Step-CA
wget https://github.com/smallstep/certificates/releases/download/v0.25.0/step-ca_0.25.0_amd64.deb
dpkg -i step-ca_0.25.0_amd64.deb

# Inicijalizacija CA
step ca init --name="Internal CA" --dns=ca.internal.example.com --address=:443
</code>

**Dodavanje ACME Provisionera:**

<code bash>
step ca provisioner add acme --type ACME
</code>

**Certbot s privatnom CA:**

<code bash>
certbot certonly \
    --server https://ca.internal.example.com/acme/acme/directory \
    --standalone \
    -d internal-server.example.com
</code>

----

===== Post-Quantum napomena =====

<WRAP round important>
**Stanje 2024:** ACME protokol i Let's Encrypt još ne podržavaju PQ potpise.
</WRAP>

**Hibridna strategija:**

<code bash>
# 1. ACME certifikat za TLS handshake (ECDSA)
certbot certonly --nginx -d example.com

# 2. Dodatni PQ certifikat za hibridni način
# (paralelno putem vlastite PKI s WvdS)
</code>

<code csharp>
// C#: Stvaranje hibridnog certifikata paralelno
using var ecdsa = ECDsa.Create(ECCurve.NamedCurves.nistP384);
var request = new CertificateRequest(
    "CN=example.com", ecdsa, HashAlgorithmName.SHA384);

// S PQ ekstenzijom za klijente spremne za budućnost
var cert = request.CreateSelfSigned(
    DateTimeOffset.UtcNow,
    DateTimeOffset.UtcNow.AddDays(90),
    CryptoMode.Hybrid);
</code>

----

===== Nadzor =====

<code bash>
# Certbot logovi
tail -f /var/log/letsencrypt/letsencrypt.log

# Provjera isteka certifikata
certbot certificates

# Prometheus Exporter (cert-exporter)
# Prati sve certifikate za istek
</code>

----

===== Rješavanje problema =====

| Problem | Uzrok | Rješenje |
|---------|-------|----------|
| ''Challenge failed'' | Port 80/443 blokiran | Provjeriti vatrozid |
| ''DNS propagation'' | DNS predmemorija | Čekati (do 60 min) ili smanjiti TTL |
| ''Rate limit exceeded'' | Previše zahtjeva | Koristiti staging server |
| ''unauthorized'' | Validacija domene nije uspjela | Provjeriti DNS zapise |

<code bash>
# Staging server za testove (bez rate limita)
certbot certonly --staging --nginx -d test.example.com

# Debug način
certbot certonly --nginx -d example.com --debug
</code>

----

===== Kontrolna lista =====

| # | Točka provjere | Gotovo |
|---|----------------|--------|
| 1 | DNS/HTTP izazov konfiguriran | ☐ |
| 2 | Certbot instaliran i testiran | ☐ |
| 3 | Auto-renewal aktiviran (Timer) | ☐ |
| 4 | Deploy-Hook konfiguriran | ☐ |
| 5 | Nadzor postavljen | ☐ |
| 6 | Obavijest o grešci | ☐ |

----

===== Povezana dokumentacija =====

  * [[.:scheduled-renewal|Zakazana obnova]] - Alternativa bez ACME
  * [[..:monitoring:ablauf-monitoring|Nadzor isteka]] - Praćenje certifikata
  * [[hr:int:pqcrypt:szenarien:tls:start|TLS/mTLS]] - Konfiguracija servera

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<< [[.:start|<- Automatizacija]] | [[.:cicd-code-signing|-> CI/CD potpisivanje koda]] >>

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//Wolfgang van der Stille @ EMSR DATA d.o.o. - Post-Quantum Cryptography Professional//

{{tag>acme letsencrypt certbot automatizacija operator}}