Develop code using keys, secrets, and certificates from Key Vault
5 minutes
5 Questions
Azure Key Vault is a cloud service that provides secure storage for keys, secrets, and certificates. When developing applications, you need to securely access these sensitive items programmatically.
**Secrets** are name-value pairs like connection strings, passwords, or API keys. To retrieve secre…Azure Key Vault is a cloud service that provides secure storage for keys, secrets, and certificates. When developing applications, you need to securely access these sensitive items programmatically.
**Secrets** are name-value pairs like connection strings, passwords, or API keys. To retrieve secrets in code, use the SecretClient class from the Azure.Security.KeyVault.Secrets package. First, authenticate using DefaultAzureCredential, then call GetSecretAsync with the secret name.
**Keys** are cryptographic keys used for encryption, decryption, signing, and verification. Use the KeyClient class from Azure.Security.KeyVault.Keys package. You can create, retrieve, and manage keys, plus perform cryptographic operations using CryptographyClient.
**Certificates** manage X.509 certificates for SSL/TLS scenarios. The CertificateClient from Azure.Security.KeyVault.Certificates handles certificate lifecycle operations including creation, renewal, and retrieval.
**Authentication** typically uses Azure Identity library with DefaultAzureCredential, which automatically tries multiple authentication methods including managed identities, Visual Studio credentials, and Azure CLI credentials.
**Example Code Pattern:**
csharp
var credential = new DefaultAzureCredential();
var secretClient = new SecretClient(new Uri("https://myvault.vault.azure.net/"), credential);
KeyVaultSecret secret = await secretClient.GetSecretAsync("MySecret");
string secretValue = secret.Value;
**Best Practices:**
- Use managed identities for Azure-hosted applications to eliminate credential management
- Grant minimum required permissions through Key Vault access policies or Azure RBAC
- Enable soft-delete and purge protection for recovery scenarios
- Use separate Key Vaults for different environments (dev, staging, production)
- Implement proper error handling for transient failures
- Cache retrieved values appropriately to reduce API calls
- Never log or expose secret values in application outputs
**Configuration Integration:** For .NET applications, use Azure.Extensions.AspNetCore.Configuration.Secrets to load Key Vault secrets as configuration values during application startup, enabling seamless integration with the configuration system.
Develop Code Using Keys, Secrets, and Certificates from Key Vault
Why Is This Important?
Azure Key Vault is a critical service for securing sensitive information in cloud applications. Understanding how to programmatically access keys, secrets, and certificates is essential for the AZ-204 exam because it demonstrates your ability to build secure applications that follow best practices for credential management. Hardcoding secrets in application code is a major security risk, and Key Vault provides the solution.
What Is Azure Key Vault?
Azure Key Vault is a cloud service that provides secure storage for: - Secrets: Connection strings, passwords, API keys, and other sensitive text values - Keys: Cryptographic keys used for encryption, decryption, signing, and verification - Certificates: X.509 certificates for SSL/TLS and authentication
How It Works
Authentication to Key Vault: Applications authenticate to Key Vault using Azure Active Directory (Azure AD). The recommended approach is using Managed Identities, which eliminates the need to store credentials in code.
Key SDK Classes: - SecretClient - Used for accessing secrets - KeyClient - Used for cryptographic key operations - CertificateClient - Used for certificate management
Connection Pattern: 1. Create a credential object (typically DefaultAzureCredential) 2. Instantiate the appropriate client with the Key Vault URI 3. Call methods to get, set, or delete secrets/keys/certificates
Code Example for Secrets:
var client = new SecretClient(new Uri("https://myvault.vault.azure.net/"), new DefaultAzureCredential()); KeyVaultSecret secret = client.GetSecret("MySecretName"); string secretValue = secret.Value;
Access Policies vs RBAC: Key Vault supports two permission models: - Vault access policies: Traditional model granting permissions per principal - Azure RBAC: Role-based access control for fine-grained permissions
Exam Tips: Answering Questions on Key Vault Development
1. DefaultAzureCredential is the preferred choice - When asked about authentication methods, this is usually the correct answer as it works across local development and Azure environments.
2. Know the client classes: SecretClient for secrets, KeyClient for keys, CertificateClient for certificates. Questions may test whether you know which client to use.
3. Managed Identity is the most secure option - For production scenarios, always prefer managed identities over service principals with client secrets.
4. Key Vault URI format: https://{vault-name}.vault.azure.net/ - Remember this pattern for exam questions.
5. Soft delete and purge protection: Understand that deleted secrets can be recovered during the retention period unless purge protection is disabled.
6. Secret versioning: Key Vault maintains versions of secrets. The latest version is returned by default, but specific versions can be retrieved.
7. Configuration integration: Know that Azure App Configuration and App Service can reference Key Vault secrets using special URI syntax.
8. Access policy permissions: Understand the difference between Get, List, Set, and Delete permissions for secrets, keys, and certificates.
9. Watch for distractor answers mentioning storing connection strings in environment variables or app settings as a secure solution - Key Vault references are the secure approach.
10. Async methods: The SDK provides both synchronous and asynchronous methods (GetSecretAsync). Know when each is appropriate.