====== Certificate Management ======

Compact examples for certificate management. -> **Details:** [[en:int:pqcrypt:szenarien:verwaltung:start|Management Scenarios]]

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===== Renew Certificate (Same Key) =====

<code csharp>
var caCert = new X509Certificate2("intermediate-ca.pfx", "password");
var oldCert = new X509Certificate2("server.pfx", "password");

var privateKey = oldCert.GetECDsaPrivateKey();

var request = new CertificateRequest(
    oldCert.SubjectName, (ECDsa)privateKey, HashAlgorithmName.SHA384);

// Copy extensions (except SKI)
foreach (var ext in oldCert.Extensions)
    if (ext.Oid?.Value != "2.5.29.14")
        request.CertificateExtensions.Add(ext);

// New serial number
var serial = new byte[20];
RandomNumberGenerator.Fill(serial);
serial[0] &= 0x7F;

var renewedCert = request.Create(caCert,
    DateTimeOffset.UtcNow, DateTimeOffset.UtcNow.AddYears(1), serial);
</code>

-> **Details:** [[en:int:pqcrypt:szenarien:verwaltung:renewal|Renewal]]

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===== Re-Key (New Key) =====

<code csharp>
var oldCert = new X509Certificate2("server.crt");
using var newKey = ECDsa.Create(ECCurve.NamedCurves.nistP384);

var request = new CertificateRequest(
    oldCert.SubjectName, newKey, HashAlgorithmName.SHA384);

// Copy SANs and EKU
if (oldCert.Extensions["2.5.29.17"] is { } san)
    request.CertificateExtensions.Add(san);
if (oldCert.Extensions["2.5.29.37"] is { } eku)
    request.CertificateExtensions.Add(eku);

// Create new certificate, revoke old one!
</code>

-> **Details:** [[en:int:pqcrypt:szenarien:verwaltung:rekey|Re-Key]]

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===== Create CRL =====

<code csharp>
var caCert = new X509Certificate2("intermediate-ca.pfx", "password");
var crlBuilder = new CertificateRevocationListBuilder();

crlBuilder.AddEntry(
    serialNumber: new byte[] { 0x01, 0x23, 0x45 },
    revocationTime: DateTimeOffset.UtcNow,
    reason: X509RevocationReason.KeyCompromise);

var crl = crlBuilder.Build(caCert,
    crlNumber: BitConverter.GetBytes(1L),
    nextUpdate: DateTimeOffset.UtcNow.AddDays(7),
    HashAlgorithmName.SHA384);

File.WriteAllBytes("intermediate.crl", crl);
</code>

-> **Details:** [[en:int:pqcrypt:szenarien:widerruf:crl_erstellen|Create CRL]]

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===== Checklist =====

**Before Expiry (30 days):**
  * Plan renewal
  * Decide renewal or re-key

**On Compromise:**
  * Immediate re-key (new key!)
  * Revoke old certificate
  * Update CRL

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<< [[.:start|<- Quick Reference]] | [[en:int:pqcrypt:szenarien:verwaltung:start|-> Management Scenarios (Details)]] >>

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

{{tag>quickreference management renewal rekey crl}}