azure-security-keyvault-keys-java – Coding skill for AI agents

Azure Key Vault Keys (Java)

Manage cryptographic keys and perform cryptographic operations in Azure Key Vault and Managed HSM.

Installation

<dependency>
    <groupId>com.azure</groupId>
    <artifactId>azure-security-keyvault-keys</artifactId>
    <version>4.9.0</version>
</dependency>

Client Creation

import com.azure.security.keyvault.keys.KeyClient;
import com.azure.security.keyvault.keys.KeyClientBuilder;
import com.azure.security.keyvault.keys.cryptography.CryptographyClient;
import com.azure.security.keyvault.keys.cryptography.CryptographyClientBuilder;
import com.azure.identity.DefaultAzureCredentialBuilder;

// Key management client
KeyClient keyClient = new KeyClientBuilder()
    .vaultUrl("https://<vault-name>.vault.azure.net")
    .credential(new DefaultAzureCredentialBuilder().build())
    .buildClient();

// Async client
KeyAsyncClient keyAsyncClient = new KeyClientBuilder()
    .vaultUrl("https://<vault-name>.vault.azure.net")
    .credential(new DefaultAzureCredentialBuilder().build())
    .buildAsyncClient();

// Cryptography client (for encrypt/decrypt/sign/verify)
CryptographyClient cryptoClient = new CryptographyClientBuilder()
    .keyIdentifier("https://<vault-name>.vault.azure.net/keys/<key-name>/<key-version>")
    .credential(new DefaultAzureCredentialBuilder().build())
    .buildClient();

Key Types

| Type | Description |

|------|-------------|

| RSA | RSA key (2048, 3072, 4096 bits) |

| RSA_HSM | RSA key in HSM |

| EC | Elliptic Curve key |

| EC_HSM | Elliptic Curve key in HSM |

| OCT | Symmetric key (Managed HSM only) |

| OCT_HSM | Symmetric key in HSM |

Create Keys

Create RSA Key

import com.azure.security.keyvault.keys.models.*;

// Simple RSA key
KeyVaultKey rsaKey = keyClient.createRsaKey(new CreateRsaKeyOptions("my-rsa-key")
    .setKeySize(2048));

System.out.println("Key name: " + rsaKey.getName());
System.out.println("Key ID: " + rsaKey.getId());
System.out.println("Key type: " + rsaKey.getKeyType());

// RSA key with options
KeyVaultKey rsaKeyWithOptions = keyClient.createRsaKey(new CreateRsaKeyOptions("my-rsa-key-2")
    .setKeySize(4096)
    .setExpiresOn(OffsetDateTime.now().plusYears(1))
    .setNotBefore(OffsetDateTime.now())
    .setEnabled(true)
    .setKeyOperations(KeyOperation.ENCRYPT, KeyOperation.DECRYPT, 
                       KeyOperation.WRAP_KEY, KeyOperation.UNWRAP_KEY)
    .setTags(Map.of("environment", "production")));

// HSM-backed RSA key
KeyVaultKey hsmKey = keyClient.createRsaKey(new CreateRsaKeyOptions("my-hsm-key")
    .setKeySize(2048)
    .setHardwareProtected(true));

Create EC Key

// EC key with P-256 curve
KeyVaultKey ecKey = keyClient.createEcKey(new CreateEcKeyOptions("my-ec-key")
    .setCurveName(KeyCurveName.P_256));

// EC key with other curves
KeyVaultKey ecKey384 = keyClient.createEcKey(new CreateEcKeyOptions("my-ec-key-384")
    .setCurveName(KeyCurveName.P_384));

KeyVaultKey ecKey521 = keyClient.createEcKey(new CreateEcKeyOptions("my-ec-key-521")
    .setCurveName(KeyCurveName.P_521));

// HSM-backed EC key
KeyVaultKey ecHsmKey = keyClient.createEcKey(new CreateEcKeyOptions("my-ec-hsm-key")
    .setCurveName(KeyCurveName.P_256)
    .setHardwareProtected(true));

Create Symmetric Key (Managed HSM only)

KeyVaultKey octKey = keyClient.createOctKey(new CreateOctKeyOptions("my-symmetric-key")
    .setKeySize(256)
    .setHardwareProtected(true));

Get Key

// Get latest version
KeyVaultKey key = keyClient.getKey("my-key");

// Get specific version
KeyVaultKey keyVersion = keyClient.getKey("my-key", "<version-id>");

// Get only key properties (no key material)
KeyProperties keyProps = keyClient.getKey("my-key").getProperties();

Update Key Properties

KeyVaultKey key = keyClient.getKey("my-key");

// Update properties
key.getProperties()
    .setEnabled(false)
    .setExpiresOn(OffsetDateTime.now().plusMonths(6))
    .setTags(Map.of("status", "archived"));

KeyVaultKey updatedKey = keyClient.updateKeyProperties(key.getProperties(),
    KeyOperation.ENCRYPT, KeyOperation.DECRYPT);

List Keys

import com.azure.core.util.paging.PagedIterable;

// List all keys
for (KeyProperties keyProps : keyClient.listPropertiesOfKeys()) {
    System.out.println("Key: " + keyProps.getName());
    System.out.println("  Enabled: " + keyProps.isEnabled());
    System.out.println("  Created: " + keyProps.getCreatedOn());
}

// List key versions
for (KeyProperties version : keyClient.listPropertiesOfKeyVersions("my-key")) {
    System.out.println("Version: " + version.getVersion());
    System.out.println("Created: " + version.getCreatedOn());
}

Delete Key

import com.azure.core.util.polling.SyncPoller;

// Begin delete (soft-delete enabled vaults)
SyncPoller<DeletedKey, Void> deletePoller = keyClient.beginDeleteKey("my-key");

// Wait for deletion
DeletedKey deletedKey = deletePoller.poll().getValue();
System.out.println("Deleted: " + deletedKey.getDeletedOn());

deletePoller.waitForCompletion();

// Recovery is an ALTERNATIVE to purge: a purged key cannot be recovered.
// Purge requires separate explicit authorization and may be blocked by purge protection.

// Recover the soft-deleted key
SyncPoller<KeyVaultKey, Void> recoverPoller = keyClient.beginRecoverDeletedKey("my-key");
recoverPoller.waitForCompletion();

Cryptographic Operations

Confirm vault/tenant, key operations and resource authorization first. Destructive disable/delete/purge operations can make dependent data unavailable; inventory consumers and recovery before writes. Use the returned versioned key ID with ciphertext/signatures for future decryption/verification after rotation. Never log decrypted production plaintext or imported private components. Backup blobs are sensitive encrypted material with restore restrictions, not a general export: write them to approved private storage without overwriting existing backups. Pin Java SDK versions and verify method support for the chosen vault/HSM and algorithm.

Encrypt/Decrypt

import com.azure.security.keyvault.keys.cryptography.models.*;

CryptographyClient cryptoClient = new CryptographyClientBuilder()
    .keyIdentifier("https://<vault>.vault.azure.net/keys/<key-name>")
    .credential(new DefaultAzureCredentialBuilder().build())
    .buildClient();

byte[] plaintext = "Hello, World!".getBytes(StandardCharsets.UTF_8);

// Encrypt
EncryptResult encryptResult = cryptoClient.encrypt(EncryptionAlgorithm.RSA_OAEP, plaintext);
byte[] ciphertext = encryptResult.getCipherText();
System.out.println("Ciphertext length: " + ciphertext.length);

// Decrypt
DecryptResult decryptResult = cryptoClient.decrypt(EncryptionAlgorithm.RSA_OAEP, ciphertext);
String decrypted = new String(decryptResult.getPlainText(), StandardCharsets.UTF_8);
System.out.println("Decrypted: " + decrypted);

Sign/Verify

import java.security.MessageDigest;

// Create digest of data
byte[] data = "Data to sign".getBytes(StandardCharsets.UTF_8);
MessageDigest md = MessageDigest.getInstance("SHA-256");
byte[] digest = md.digest(data);

// Sign
SignResult signResult = cryptoClient.sign(SignatureAlgorithm.RS256, digest);
byte[] signature = signResult.getSignature();

// Verify
VerifyResult verifyResult = cryptoClient.verify(SignatureAlgorithm.RS256, digest, signature);
System.out.println("Valid signature: " + verifyResult.isValid());

Wrap/Unwrap Key

// Key to wrap (e.g., AES key)
byte[] keyToWrap = new byte[32];  // 256-bit key
new SecureRandom().nextBytes(keyToWrap);

// Wrap
WrapResult wrapResult = cryptoClient.wrapKey(KeyWrapAlgorithm.RSA_OAEP, keyToWrap);
byte[] wrappedKey = wrapResult.getEncryptedKey();

// Unwrap
UnwrapResult unwrapResult = cryptoClient.unwrapKey(KeyWrapAlgorithm.RSA_OAEP, wrappedKey);
byte[] unwrappedKey = unwrapResult.getKey();

Backup and Restore

// Backup
byte[] backup = keyClient.backupKey("my-key");

// Save backup to file
Files.write(Paths.get("key-backup.blob"), backup);

// Restore
byte[] backupData = Files.readAllBytes(Paths.get("key-backup.blob"));
KeyVaultKey restoredKey = keyClient.restoreKeyBackup(backupData);

Key Rotation

// Rotate to new version
KeyVaultKey rotatedKey = keyClient.rotateKey("my-key");
System.out.println("New version: " + rotatedKey.getProperties().getVersion());

// Set rotation policy
KeyRotationPolicy policy = new KeyRotationPolicy()
    .setExpiresIn("P90D")  // Expire after 90 days
    .setLifetimeActions(Arrays.asList(
        new KeyRotationLifetimeAction(KeyRotationPolicyAction.ROTATE)
            .setTimeBeforeExpiry("P30D")));  // Rotate 30 days before expiry

keyClient.updateKeyRotationPolicy("my-key", policy);

// Get rotation policy
KeyRotationPolicy currentPolicy = keyClient.getKeyRotationPolicy("my-key");

Import Key

import com.azure.security.keyvault.keys.models.ImportKeyOptions;

… (full content is in the download package)