Scenario 2.3: Creare CSR Multi-SAN

Questo scenario descrive la creazione di un CSR con piu Subject Alternative Names (SAN). Questo e necessario per certificati che devono proteggere piu domini, sottodomini o indirizzi IP.

Casi d'uso:

• Certificati multi-dominio (certificati SAN)
• Wildcard + domini espliciti combinati
• Nomi interni + esterni
• Load Balancer con piu backend

using WvdS.Security.Cryptography.X509Certificates.Extensions.PQ;
 
using var ctx = PqCryptoContext.Initialize();
using var key = ctx.GenerateKeyPair(PqAlgorithm.MlDsa65);
 
var dn = new DnBuilder()
    .AddCN("example.com")  // Dominio primario
    .AddO("Example SRL")
    .AddC("IT")
    .Build();
 
// Multi-SAN con diversi tipi
var extensions = new ExtBuilder()
    .SubjectAlternativeName(new[] {
        // Nomi DNS
        "dns:example.com",
        "dns:www.example.com",
        "dns:api.example.com",
        "dns:app.example.com",
        "dns:*.dev.example.com",      // Wildcard per Dev
 
        // Indirizzi IP (per accessi interni)
        "ip:10.0.0.100",
        "ip:192.168.1.50",
 
        // IPv6
        "ip:2001:db8::1"
    })
    .KeyUsage(KeyUsageFlags.DigitalSignature | KeyUsageFlags.KeyEncipherment)
    .ExtendedKeyUsage(ExtKeyUsage.ServerAuth)
    .Build();
 
var csr = ctx.CreateCertificateRequest(key, dn, extensions);
 
// Visualizzare tutti i SAN
Console.WriteLine("Subject Alternative Names:");
foreach (var san in csr.SubjectAlternativeNames)
{
    Console.WriteLine($"  - {san}");
}
 
File.WriteAllText("multi-san.csr.pem", csr.ToPem());

var extensions = new ExtBuilder()
    .SubjectAlternativeName(new[] {
        "dns:example.com",           // Dominio root (Wildcard non lo copre!)
        "dns:*.example.com",         // Tutti i sottodomini 1o livello
        "dns:*.api.example.com",     // Sottodomini API
        "dns:legacy.old-domain.com"  // Dominio alternativo
    })
    .Build();

var extensions = new ExtBuilder()
    .SubjectAlternativeName(new[] {
        // DNS Kubernetes Service
        "dns:my-service",
        "dns:my-service.default",
        "dns:my-service.default.svc",
        "dns:my-service.default.svc.cluster.local",
 
        // Headless Service (Pod DNS)
        "dns:*.my-service.default.svc.cluster.local",
 
        // Dominio Ingress esterno
        "dns:api.example.com"
    })
    .Build();

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