~~NOTOC~~
====== Scenarij 6.1: Ustvarjanje CRL ======

<WRAP round info>
**Kategorija:** [[.:start|Preklic (Revocation)]] \\
**Kompleksnost:** Srednja \\
**Predpogoji:** Certifikat in ključ CA \\
**Ocenjeni čas:** 15-20 minut
</WRAP>

----

===== Opis =====

Ta scenarij opisuje **ustvarjanje seznama preklicanih certifikatov (CRL)** po RFC 5280. CRL so podpisani seznami preklicanih certifikatov, ki jih objavljajo CA.

**Polja CRL:**
  * **issuer** - DN izdajateljske CA
  * **thisUpdate** - Čas izdaje
  * **nextUpdate** - Naslednja načrtovana posodobitev
  * **revokedCertificates** - Seznam preklicanih serijskih številk
  * **signature** - Podpis CA

----

===== Potek dela =====

<mermaid>
flowchart LR
    REV[Preklicani certifikati] --> BUILD[CRL Builder]
    BUILD --> SIGN[Podpis s CA]
    SIGN --> PUBLISH[Objava]
    PUBLISH --> CDP[Posodobitev CDP URL]

    style SIGN fill:#e8f5e9
</mermaid>

----

===== Primer kode (C#) =====

<code csharp>
using WvdS.Security.Cryptography.X509Certificates.Extensions.PQ;
using System.Security.Cryptography.X509Certificates;

using var ctx = PqCryptoContext.Initialize();

// Nalaganje CA
var caCert = ctx.LoadCertificate("intermediate-ca.crt.pem");
var caKey = ctx.LoadPrivateKey("intermediate-ca.key.pem", "CaPassword!");

// Ustvarjanje CRL Builder
var crlBuilder = new CertificateRevocationListBuilder();

// Dodajanje preklicanih certifikatov
crlBuilder.AddEntry(
    serialNumber: new byte[] { 0x01, 0x02, 0x03 },
    revocationTime: new DateTimeOffset(2024, 6, 15, 10, 30, 0, TimeSpan.Zero),
    reason: X509RevocationReason.KeyCompromise
);

crlBuilder.AddEntry(
    serialNumber: new byte[] { 0x01, 0x02, 0x04 },
    revocationTime: DateTimeOffset.UtcNow.AddDays(-7),
    reason: X509RevocationReason.CessationOfOperation
);

// Generiranje CRL
byte[] crlBytes = crlBuilder.Build(
    issuerCertificate: caCert,
    crlNumber: BigInteger.Parse("1000"),
    nextUpdate: DateTimeOffset.UtcNow.AddDays(7),
    hashAlgorithm: HashAlgorithmName.SHA256,
    rsaSignaturePadding: null,  // Za PQ ni relevantno
    mode: CryptoMode.Hybrid
);

// Shranjevanje CRL
File.WriteAllBytes("intermediate-ca.crl", crlBytes);

// Pretvorba CRL v PEM
var crlPem = ctx.ToPem(crlBytes, "X509 CRL");
File.WriteAllText("intermediate-ca.crl.pem", crlPem);

Console.WriteLine("CRL ustvarjen:");
Console.WriteLine($"  Vnosi: {crlBuilder.Entries.Count}");
Console.WriteLine($"  CRL Number: 1000");
Console.WriteLine($"  Next Update: {DateTimeOffset.UtcNow.AddDays(7):yyyy-MM-dd}");
</code>

----

===== Posodabljanje CRL iz obstoječega CRL =====

<code csharp>
public class CrlUpdater
{
    public byte[] UpdateCrl(
        byte[] existingCrl,
        X509Certificate2 caCert,
        AsymmetricAlgorithm caKey,
        IEnumerable<CrlEntry>? newEntries = null)
    {
        using var ctx = PqCryptoContext.Initialize();

        // Razčlenjevanje obstoječega CRL
        var parsedCrl = ctx.ParseCrl(existingCrl);

        // Nov Builder z obstoječimi vnosi
        var builder = new CertificateRevocationListBuilder();

        foreach (var entry in parsedCrl.Entries)
        {
            builder.AddEntry(entry.SerialNumber, entry.RevocationTime, entry.Reason);
        }

        // Dodajanje novih vnosov
        if (newEntries != null)
        {
            foreach (var entry in newEntries)
            {
                builder.AddEntry(entry.SerialNumber, entry.RevocationTime, entry.Reason);
            }
        }

        // Nova CRL-številka (povečana)
        var newCrlNumber = parsedCrl.CrlNumber + 1;

        // Ustvarjanje novega CRL
        return builder.Build(
            issuerCertificate: caCert,
            crlNumber: newCrlNumber,
            nextUpdate: DateTimeOffset.UtcNow.AddDays(7),
            hashAlgorithm: HashAlgorithmName.SHA256,
            mode: CryptoMode.Hybrid
        );
    }
}
</code>

----

===== CRL Extensions =====

<code csharp>
// CRL z razširitvami
var crlBuilder = new CertificateRevocationListBuilder();

// CRL Extensions
crlBuilder.AddExtension(
    oid: "2.5.29.20",  // CRL Number
    critical: false,
    value: BuildCrlNumberExtension(1001)
);

crlBuilder.AddExtension(
    oid: "2.5.29.35",  // Authority Key Identifier
    critical: false,
    value: BuildAkiExtension(caCert)
);

crlBuilder.AddExtension(
    oid: "2.5.29.28",  // Issuing Distribution Point
    critical: true,
    value: BuildIdpExtension(
        distributionPoint: "http://crl.example.com/intermediate.crl",
        onlyContainUserCerts: true
    )
);

// Entry Extensions (za vsak preklicanem certifikat)
crlBuilder.AddEntry(
    serialNumber: revokedSerial,
    revocationTime: DateTimeOffset.UtcNow,
    reason: X509RevocationReason.KeyCompromise,
    extensions: new X509ExtensionCollection
    {
        // Invalidity Date (kdaj je bil dejansko ogrožen)
        BuildInvalidityDateExtension(compromiseDate),
        // Certificate Issuer (če je Indirect CRL)
        BuildCertificateIssuerExtension(certIssuerDn)
    }
);
</code>

----

===== Razlogi za preklic (RFC 5280) =====

^  Koda  ^  Razlog  ^  Opis  ^
| 0 | unspecified | Brez specifičnega razloga |
| 1 | keyCompromise | Ključ ogrožen |
| 2 | cACompromise | CA ogrožena |
| 3 | affiliationChanged | Pripadnost spremenjena |
| 4 | superseded | Zamenjano z novim certifikatom |
| 5 | cessationOfOperation | Delovanje ustavljeno |
| 6 | certificateHold | Začasno blokirano |
| 8 | removeFromCRL | Odstranitev iz CRL (odprava blokade) |
| 9 | privilegeWithdrawn | Pooblastilo odvzeto |
| 10 | aACompromise | Atributna agencija ogrožena |

----

===== Konfiguracija CRL Distribution Point =====

<code csharp>
// Izdaja certifikata s CDP
var cert = ctx.IssueCertificate(
    csr,
    issuerCert: caCert,
    issuerKey: caKey,
    extensions: new ExtBuilder()
        .CrlDistributionPoint(
            uri: "http://crl.example.com/intermediate.crl",
            ldapUri: "ldap://ldap.example.com/cn=Intermediate-CA,o=Example,c=DE?certificateRevocationList"
        )
        .Build()
);
</code>

----

===== Panožne zahteve za CRL =====

^  Panoga  ^  Maks. nextUpdate  ^  Format  ^  Distribucija  ^
| **WebPKI** | 7 dni | DER | HTTP |
| **Enterprise** | 24 ur | DER/PEM | HTTP, LDAP |
| **Energetika/SCADA** | 30 dni | DER | Brez povezave |
| **Zdravstvo** | 24 ur | DER | HTTP |

<WRAP round tip>
**Najboljša praksa:** Posodobite CRL pred nextUpdate (50-75% obdobja veljavnosti).
</WRAP>

----

===== Povezani scenariji =====

^  Povezava  ^  Scenarij  ^  Opis  ^
| **Alternativa** | [[.:ocsp_responder|6.2 OCSP strežnik]] | Sprotno preverjanje |
| **Razširitev** | [[.:delta_crl|6.3 Delta-CRL]] | Inkrementalne posodobitve |
| **Predpogoj** | [[.:zertifikat_widerrufen|6.4 Preklic certifikata]] | Postopek preklica |

----

<< [[.:start|← Pregled preklica]] | [[sl:int:pqcrypt:szenarien:start|↑ Scenariji]] | [[.:ocsp_responder|6.2 OCSP strežnik →]] >>

{{tag>szenario widerruf crl revocation pki}}

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