~~NOTOC~~
====== Scenario 4.4: Certificate and Key Backup ======

<WRAP round info>
**Category:** [[.:start|Certificate Management]] \\
**Complexity:** ⭐⭐⭐⭐ (High) \\
**Prerequisites:** Certificates and keys available \\
**Estimated Time:** 20-30 Minutes
</WRAP>

----

===== Description =====

This scenario describes the **secure backup** of certificates, private keys, and CA infrastructure. A proper backup concept is critical for:

  * **Disaster Recovery** - Restoration after system failure
  * **Business Continuity** - Operational continuation
  * **Compliance** - Audit requirements
  * **Key Escrow** - Key custody

<WRAP round alert>
**CRITICAL:** Private keys are the most valuable asset! Backups must be:
  * Encrypted
  * Stored offline
  * Access protected
  * Regularly tested
</WRAP>

----

===== Workflow =====

<mermaid>
flowchart TD
    START[Initiate Backup] --> COLLECT[Collect Data]
    COLLECT --> ENCRYPT[Encrypt]
    ENCRYPT --> SIGN[Sign]
    SIGN --> STORE1[Primary Storage]
    SIGN --> STORE2[Secondary Storage]
    STORE1 --> VERIFY[Verify]
    STORE2 --> VERIFY
    VERIFY --> LOG[Audit Log]

    style ENCRYPT fill:#fff3e0
    style STORE1 fill:#e8f5e9
    style STORE2 fill:#e8f5e9
</mermaid>

----

===== Code Example (C#) =====

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

using var ctx = PqCryptoContext.Initialize();

// Backup configuration
var backupConfig = new BackupConfiguration
{
    EncryptionPassword = "BackupPassword!Secure2024",
    OutputPath = "backup/",
    Timestamp = DateTime.UtcNow.ToString("yyyyMMdd-HHmmss"),
    IncludeChain = true
};

// Load CA certificate and key
var caCert = ctx.LoadCertificate("root-ca.crt.pem");
var caKey = ctx.LoadPrivateKey("root-ca.key.pem", "CaPassword!");

// Create encrypted PFX
var pfxData = ctx.ExportToPfx(
    certificate: caCert,
    privateKey: caKey,
    chain: null,  // Root has no chain
    password: backupConfig.EncryptionPassword,
    friendlyName: $"Root-CA Backup {backupConfig.Timestamp}"
);

// Backup file with metadata
var backupPath = Path.Combine(
    backupConfig.OutputPath,
    $"root-ca-backup-{backupConfig.Timestamp}.pfx"
);

Directory.CreateDirectory(backupConfig.OutputPath);
File.WriteAllBytes(backupPath, pfxData);

// Calculate checksum
var checksum = ctx.ComputeSha256(pfxData);
var checksumPath = backupPath + ".sha256";
File.WriteAllText(checksumPath, Convert.ToHexString(checksum));

// Save metadata
var metadata = new BackupMetadata
{
    BackupDate = DateTime.UtcNow,
    Subject = caCert.Subject,
    SerialNumber = caCert.SerialNumber,
    NotAfter = caCert.NotAfter,
    Checksum = Convert.ToHexString(checksum),
    Algorithm = caCert.PublicKey.Oid.FriendlyName
};

var metadataPath = backupPath + ".meta.json";
File.WriteAllText(metadataPath, JsonSerializer.Serialize(metadata, new JsonSerializerOptions
{
    WriteIndented = true
}));

Console.WriteLine("Backup created:");
Console.WriteLine($"  File: {backupPath}");
Console.WriteLine($"  SHA256: {metadata.Checksum}");
Console.WriteLine($"  Size: {new FileInfo(backupPath).Length:N0} Bytes");
</code>

----

===== Complete CA Backup =====

<code csharp>
public class CaBackupManager
{
    public void CreateFullBackup(string caDirectory, string backupPassword, string outputPath)
    {
        var timestamp = DateTime.UtcNow.ToString("yyyyMMdd-HHmmss");
        var backupDir = Path.Combine(outputPath, $"ca-backup-{timestamp}");
        Directory.CreateDirectory(backupDir);

        using var ctx = PqCryptoContext.Initialize();

        // 1. Root CA
        BackupCertificateAndKey(ctx, caDirectory, "root-ca", backupDir, backupPassword);

        // 2. All Intermediate CAs
        foreach (var intCaDir in Directory.GetDirectories(caDirectory, "intermediate-*"))
        {
            var name = Path.GetFileName(intCaDir);
            BackupCertificateAndKey(ctx, intCaDir, name, backupDir, backupPassword);
        }

        // 3. CRL files
        var crlDir = Path.Combine(backupDir, "crls");
        Directory.CreateDirectory(crlDir);
        foreach (var crl in Directory.GetFiles(caDirectory, "*.crl", SearchOption.AllDirectories))
        {
            File.Copy(crl, Path.Combine(crlDir, Path.GetFileName(crl)));
        }

        // 4. Configuration files
        var configDir = Path.Combine(backupDir, "config");
        Directory.CreateDirectory(configDir);
        foreach (var config in Directory.GetFiles(caDirectory, "*.json"))
        {
            File.Copy(config, Path.Combine(configDir, Path.GetFileName(config)));
        }

        // 5. Create manifest
        CreateBackupManifest(backupDir, timestamp);

        Console.WriteLine($"Complete CA backup created: {backupDir}");
    }

    private void BackupCertificateAndKey(
        PqCryptoContext ctx,
        string sourceDir,
        string name,
        string backupDir,
        string password)
    {
        var certPath = Path.Combine(sourceDir, $"{name}.crt.pem");
        var keyPath = Path.Combine(sourceDir, $"{name}.key.pem");

        if (!File.Exists(certPath)) return;

        var cert = ctx.LoadCertificate(certPath);

        // Certificate in cleartext (PEM)
        var certBackup = Path.Combine(backupDir, "certs", $"{name}.crt.pem");
        Directory.CreateDirectory(Path.GetDirectoryName(certBackup)!);
        cert.ToPemFile(certBackup);

        // Key encrypted (if present)
        if (File.Exists(keyPath))
        {
            // Encrypt key with new password
            var key = ctx.LoadPrivateKey(keyPath, "OriginalPassword!");  // Adjust!
            var keyBackup = Path.Combine(backupDir, "keys", $"{name}.key.pem.enc");
            Directory.CreateDirectory(Path.GetDirectoryName(keyBackup)!);
            key.ToEncryptedPemFile(keyBackup, password);
        }
    }

    private void CreateBackupManifest(string backupDir, string timestamp)
    {
        var manifest = new
        {
            Version = "1.0",
            Timestamp = timestamp,
            CreatedAt = DateTime.UtcNow,
            Contents = new
            {
                Certificates = Directory.GetFiles(Path.Combine(backupDir, "certs"), "*.pem").Length,
                Keys = Directory.GetFiles(Path.Combine(backupDir, "keys"), "*.enc").Length,
                CRLs = Directory.GetFiles(Path.Combine(backupDir, "crls"), "*.crl").Length,
                Configs = Directory.GetFiles(Path.Combine(backupDir, "config"), "*.json").Length
            }
        };

        var manifestPath = Path.Combine(backupDir, "MANIFEST.json");
        File.WriteAllText(manifestPath, JsonSerializer.Serialize(manifest, new JsonSerializerOptions
        {
            WriteIndented = true
        }));
    }
}
</code>

----

===== Backup Verification =====

<code csharp>
public bool VerifyBackup(string backupPath, string password)
{
    using var ctx = PqCryptoContext.Initialize();

    // 1. Verify checksum
    var expectedChecksum = File.ReadAllText(backupPath + ".sha256");
    var actualData = File.ReadAllBytes(backupPath);
    var actualChecksum = Convert.ToHexString(ctx.ComputeSha256(actualData));

    if (expectedChecksum != actualChecksum)
    {
        Console.WriteLine("ERROR: Checksum mismatch!");
        return false;
    }

    // 2. Load PFX (tests password and integrity)
    try
    {
        var (cert, key) = ctx.ImportFromPfx(actualData, password);
        Console.WriteLine($"Backup OK: {cert.Subject}");
        Console.WriteLine($"  Valid until: {cert.NotAfter:yyyy-MM-dd}");
        Console.WriteLine($"  Key: {(key != null ? "Present" : "Missing")}");
        return true;
    }
    catch (CryptographicException ex)
    {
        Console.WriteLine($"ERROR: {ex.Message}");
        return false;
    }
}
</code>

----

===== Industry-Specific Backup Requirements =====

^  Industry  ^  Regulation  ^  Backup Frequency  ^  Retention  ^  Special Feature  ^
| **Financial Sector** | MaRisk | Daily | 10 years | Geo-redundancy mandatory |
| **Healthcare** | GDPR | Daily | 30 years | Air-gap storage |
| **Energy** | KRITIS-VO | Weekly | 10 years | Offline media |
| **Automotive** | UNECE R155 | Monthly | Vehicle lifetime | OTA recovery |

----

===== Backup Strategy 3-2-1 =====

<WRAP round tip>
**3-2-1 Rule:**
  * **3** copies of data
  * **2** different media types
  * **1** copy off-site
</WRAP>

| Copy | Medium | Location | Purpose |
|-------|--------|-----|-------|
| 1 | Server storage | Data center | Operational |
| 2 | Tape/NAS | Building B | Disaster recovery |
| 3 | Cloud (encrypted) | Different location | Geo-redundancy |

----

===== Related Scenarios =====

^  Relationship  ^  Scenario  ^  Description  ^
| **Next Step** | [[.:archivierung|4.3 Archival]] | Long-term retention |
| **Related** | [[en:int:pqcrypt:szenarien:schluessel:speicherung|11.2 Key Storage]] | Key storage |
| **Related** | [[en:int:pqcrypt:szenarien:importexport:pfx_export|12.2 PFX Export]] | Export format |

----

<< [[.:archivierung|← 4.3 Archival]] | [[.:start|↑ Management Overview]] | [[en:int:pqcrypt:szenarien:start|→ All Scenarios]] >>

{{tag>scenario management backup disaster-recovery pfx}}

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