====== Azure Key Vault ======

<WRAP round info>
**Cloud:** Microsoft Azure \\
**HSM Level:** FIPS 140-2 Level 2 (Standard) / Level 3 (Managed HSM) \\
**PQ Support:** Not yet available (as of 2024)
</WRAP>

Integration of Azure Key Vault for certificate and key management.

----

===== Architecture =====

<mermaid>
flowchart TB
    subgraph AZURE["AZURE"]
        subgraph KV["Key Vault"]
            K[Keys]
            S[Secrets]
            C[Certificates]
        end
        subgraph HSM["Managed HSM"]
            H[HSM Keys]
        end
        subgraph APPS["Applications"]
            A1[App Service]
            A2[AKS]
            A3[Functions]
        end
    end

    subgraph ONPREM["ON-PREM"]
        CA[Internal CA]
    end

    CA -->|Import| C
    K --> A1 & A2 & A3
    C --> A1 & A2 & A3
    H -->|Premium| K

    style KV fill:#e3f2fd
    style HSM fill:#e8f5e9
</mermaid>

----

===== Setup =====

==== Create Key Vault ====

<code bash>
# Azure CLI
az login

# Resource Group
az group create --name rg-pki --location germanywestcentral

# Key Vault (Standard)
az keyvault create \
    --name kv-pki-prod \
    --resource-group rg-pki \
    --location germanywestcentral \
    --sku standard

# Key Vault (Premium with HSM)
az keyvault create \
    --name kv-pki-prod-hsm \
    --resource-group rg-pki \
    --location germanywestcentral \
    --sku premium
</code>

==== Managed HSM (FIPS 140-2 Level 3) ====

<code bash>
# Create Managed HSM
az keyvault create \
    --hsm-name hsm-pki-prod \
    --resource-group rg-pki \
    --location germanywestcentral \
    --administrators "user@example.com"

# Activate HSM (requires 3 RSA keys)
az keyvault security-domain download \
    --hsm-name hsm-pki-prod \
    --sd-wrapping-keys key1.pem key2.pem key3.pem \
    --sd-quorum 2 \
    --security-domain-file sd.json
</code>

----

===== Manage Certificates =====

==== Import Certificate ====

<code bash>
# Import PFX certificate
az keyvault certificate import \
    --vault-name kv-pki-prod \
    --name server-cert \
    --file server.pfx \
    --password "pfx-password"
</code>

<code csharp>
// C# - Import certificate
using Azure.Identity;
using Azure.Security.KeyVault.Certificates;

var client = new CertificateClient(
    new Uri("https://kv-pki-prod.vault.azure.net/"),
    new DefaultAzureCredential());

// Import PFX
byte[] pfxData = File.ReadAllBytes("server.pfx");
var importOptions = new ImportCertificateOptions("server-cert", pfxData)
{
    Password = "pfx-password"
};

KeyVaultCertificateWithPolicy cert = await client.ImportCertificateAsync(importOptions);
Console.WriteLine($"Imported: {cert.Name}, Thumbprint: {cert.Properties.X509Thumbprint}");
</code>

==== Retrieve Certificate ====

<code csharp>
// C# - Load certificate from Key Vault
using Azure.Identity;
using Azure.Security.KeyVault.Secrets;
using System.Security.Cryptography.X509Certificates;

var secretClient = new SecretClient(
    new Uri("https://kv-pki-prod.vault.azure.net/"),
    new DefaultAzureCredential());

// Retrieve certificate as secret (includes private key)
KeyVaultSecret secret = await secretClient.GetSecretAsync("server-cert");

byte[] certBytes = Convert.FromBase64String(secret.Value);
var certificate = new X509Certificate2(certBytes);

Console.WriteLine($"Subject: {certificate.Subject}");
Console.WriteLine($"Has Private Key: {certificate.HasPrivateKey}");
</code>

==== Create Certificate with Key Vault CA ====

<code bash>
# Define certificate policy
az keyvault certificate create \
    --vault-name kv-pki-prod \
    --name app-cert \
    --policy @cert-policy.json
</code>

<code json>
// cert-policy.json
{
  "issuerParameters": {
    "name": "Self"
  },
  "keyProperties": {
    "exportable": true,
    "keySize": 4096,
    "keyType": "RSA",
    "reuseKey": false
  },
  "secretProperties": {
    "contentType": "application/x-pkcs12"
  },
  "x509CertificateProperties": {
    "subject": "CN=app.example.com",
    "subjectAlternativeNames": {
      "dnsNames": ["app.example.com", "*.app.example.com"]
    },
    "validityInMonths": 12
  }
}
</code>

----

===== Keys for Signing =====

==== Create Signing Key ====

<code bash>
# EC key for signatures
az keyvault key create \
    --vault-name kv-pki-prod \
    --name signing-key \
    --kty EC \
    --curve P-384

# RSA key
az keyvault key create \
    --vault-name kv-pki-prod \
    --name rsa-signing-key \
    --kty RSA \
    --size 4096
</code>

==== Remote Signing ====

<code csharp>
// C# - Sign with Azure Key Vault key
using Azure.Identity;
using Azure.Security.KeyVault.Keys;
using Azure.Security.KeyVault.Keys.Cryptography;

var keyClient = new KeyClient(
    new Uri("https://kv-pki-prod.vault.azure.net/"),
    new DefaultAzureCredential());

KeyVaultKey key = await keyClient.GetKeyAsync("signing-key");
var cryptoClient = new CryptographyClient(key.Id, new DefaultAzureCredential());

// Sign data
byte[] dataToSign = Encoding.UTF8.GetBytes("Important document");
byte[] digest = SHA384.HashData(dataToSign);

SignResult signature = await cryptoClient.SignAsync(
    SignatureAlgorithm.ES384,
    digest);

Console.WriteLine($"Signature: {Convert.ToBase64String(signature.Signature)}");

// Verify signature
VerifyResult verified = await cryptoClient.VerifyAsync(
    SignatureAlgorithm.ES384,
    digest,
    signature.Signature);

Console.WriteLine($"Verified: {verified.IsValid}");
</code>

----

===== App Service / AKS Integration =====

==== App Service ====

<code bash>
# Key Vault reference in App Settings
az webapp config appsettings set \
    --name myapp \
    --resource-group rg-app \
    --settings "Certificate=@Microsoft.KeyVault(VaultName=kv-pki-prod;SecretName=server-cert)"

# Enable Managed Identity
az webapp identity assign \
    --name myapp \
    --resource-group rg-app

# Key Vault Access Policy
az keyvault set-policy \
    --name kv-pki-prod \
    --object-id <managed-identity-object-id> \
    --secret-permissions get list \
    --certificate-permissions get list
</code>

==== Azure Kubernetes Service (AKS) ====

<code yaml>
# secrets-store-csi-driver.yaml
apiVersion: secrets-store.csi.x-k8s.io/v1
kind: SecretProviderClass
metadata:
  name: azure-keyvault-tls
spec:
  provider: azure
  parameters:
    usePodIdentity: "false"
    useVMManagedIdentity: "true"
    userAssignedIdentityID: "<client-id>"
    keyvaultName: "kv-pki-prod"
    objects: |
      array:
        - |
          objectName: server-cert
          objectType: secret
    tenantId: "<tenant-id>"
  secretObjects:
    - secretName: tls-secret
      type: kubernetes.io/tls
      data:
        - objectName: server-cert
          key: tls.crt
        - objectName: server-cert
          key: tls.key
</code>

<code yaml>
# pod-with-keyvault-cert.yaml
apiVersion: v1
kind: Pod
metadata:
  name: app-with-tls
spec:
  containers:
    - name: app
      image: myapp:latest
      volumeMounts:
        - name: secrets-store
          mountPath: "/mnt/secrets-store"
          readOnly: true
  volumes:
    - name: secrets-store
      csi:
        driver: secrets-store.csi.k8s.io
        readOnly: true
        volumeAttributes:
          secretProviderClass: "azure-keyvault-tls"
</code>

----

===== Monitoring =====

<code bash>
# Enable diagnostics
az monitor diagnostic-settings create \
    --name kv-diagnostics \
    --resource /subscriptions/<sub>/resourceGroups/rg-pki/providers/Microsoft.KeyVault/vaults/kv-pki-prod \
    --logs '[{"category": "AuditEvent", "enabled": true}]' \
    --metrics '[{"category": "AllMetrics", "enabled": true}]' \
    --workspace <log-analytics-workspace-id>
</code>

**KQL Query for certificate operations:**

<code>
AzureDiagnostics
| where ResourceProvider == "MICROSOFT.KEYVAULT"
| where OperationName contains "Certificate"
| project TimeGenerated, OperationName, ResultType, CallerIPAddress, identity_claim_upn_s
| order by TimeGenerated desc
</code>

----

===== Checklist =====

| # | Checkpoint | Done |
|---|------------|------|
| 1 | Key Vault created | |
| 2 | Access policies configured | |
| 3 | Certificates imported | |
| 4 | Managed Identity for apps | |
| 5 | Diagnostics enabled | |
| 6 | Backup configured | |

----

===== Related Documentation =====

  * [[.:aws-kms|AWS KMS]] - Alternative cloud
  * [[.:hashicorp-vault|HashiCorp Vault]] - Multi-cloud
  * [[..:automatisierung:cert-manager-k8s|Kubernetes Cert-Manager]] - K8s integration

----

<< [[.:start|<- Cloud Integration]] | [[.:aws-kms|-> AWS KMS]] >>

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

{{tag>azure keyvault hsm cloud operator}}