diff --git a/kms/createKeyAsymmetricDecrypt.js b/kms/createKeyAsymmetricDecrypt.js
index 6bfaee0522..e688fdbefa 100644
--- a/kms/createKeyAsymmetricDecrypt.js
+++ b/kms/createKeyAsymmetricDecrypt.js
@@ -47,6 +47,10 @@ async function main(
         versionTemplate: {
           algorithm: 'RSA_DECRYPT_OAEP_2048_SHA256',
         },
+
+        // Optional: customize how long key versions should be kept before
+        // destroying.
+        destroyScheduledDuration: {seconds: 60 * 60 * 24},
       },
     });
 
@@ -59,8 +63,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/createKeyAsymmetricSign.js b/kms/createKeyAsymmetricSign.js
index 9d0314dc14..73a998984b 100644
--- a/kms/createKeyAsymmetricSign.js
+++ b/kms/createKeyAsymmetricSign.js
@@ -47,6 +47,10 @@ async function main(
         versionTemplate: {
           algorithm: 'RSA_SIGN_PKCS1_2048_SHA256',
         },
+
+        // Optional: customize how long key versions should be kept before
+        // destroying.
+        destroyScheduledDuration: {seconds: 60 * 60 * 24},
       },
     });
 
@@ -59,8 +63,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/createKeyHsm.js b/kms/createKeyHsm.js
index 5ccdc94767..9592c3e770 100644
--- a/kms/createKeyHsm.js
+++ b/kms/createKeyHsm.js
@@ -48,6 +48,10 @@ async function main(
           algorithm: 'GOOGLE_SYMMETRIC_ENCRYPTION',
           protectionLevel: 'HSM',
         },
+
+        // Optional: customize how long key versions should be kept before
+        // destroying.
+        destroyScheduledDuration: {seconds: 60 * 60 * 24},
       },
     });
 
@@ -60,8 +64,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/createKeyLabels.js b/kms/createKeyLabels.js
index 71460cf523..412eca44d8 100644
--- a/kms/createKeyLabels.js
+++ b/kms/createKeyLabels.js
@@ -63,8 +63,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/createKeyMac.js b/kms/createKeyMac.js
new file mode 100644
index 0000000000..ce117b2be6
--- /dev/null
+++ b/kms/createKeyMac.js
@@ -0,0 +1,76 @@
+// Copyright 2021 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+'use strict';
+
+async function main(
+  projectId = 'my-project',
+  locationId = 'us-east1',
+  keyRingId = 'my-key-ring',
+  id = 'my-mac-key'
+) {
+  // [START kms_create_key_mac]
+  //
+  // TODO(developer): Uncomment these variables before running the sample.
+  //
+  // const projectId = 'my-project';
+  // const locationId = 'us-east1';
+  // const keyRingId = 'my-key-ring';
+  // const id = 'my-mac-key';
+
+  // Imports the Cloud KMS library
+  const {KeyManagementServiceClient} = require('@google-cloud/kms');
+
+  // Instantiates a client
+  const client = new KeyManagementServiceClient();
+
+  // Build the parent key ring name
+  const keyRingName = client.keyRingPath(projectId, locationId, keyRingId);
+
+  async function createKeyMac() {
+    const [key] = await client.createCryptoKey({
+      parent: keyRingName,
+      cryptoKeyId: id,
+      cryptoKey: {
+        purpose: 'MAC',
+        versionTemplate: {
+          algorithm: 'HMAC_SHA256',
+        },
+
+        // Optional: customize how long key versions should be kept before
+        // destroying.
+        destroyScheduledDuration: {seconds: 60 * 60 * 24},
+      },
+    });
+
+    console.log(`Created mac key: ${key.name}`);
+    return key;
+  }
+
+  return createKeyMac();
+  // [END kms_create_key_mac]
+}
+module.exports.main = main;
+
+/* c8 ignore next 10 */
+if (require.main === module) {
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+}
diff --git a/kms/createKeyRing.js b/kms/createKeyRing.js
index 90820afa40..36b2110fa9 100644
--- a/kms/createKeyRing.js
+++ b/kms/createKeyRing.js
@@ -51,8 +51,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/createKeyRotationSchedule.js b/kms/createKeyRotationSchedule.js
index 93d0d04c54..23f3d5fe44 100644
--- a/kms/createKeyRotationSchedule.js
+++ b/kms/createKeyRotationSchedule.js
@@ -69,8 +69,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/createKeySymmetricEncryptDecrypt.js b/kms/createKeySymmetricEncryptDecrypt.js
index 6f1ab1df00..e4677347bd 100644
--- a/kms/createKeySymmetricEncryptDecrypt.js
+++ b/kms/createKeySymmetricEncryptDecrypt.js
@@ -59,8 +59,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/createKeyVersion.js b/kms/createKeyVersion.js
index 03747cb7b0..5230f7638e 100644
--- a/kms/createKeyVersion.js
+++ b/kms/createKeyVersion.js
@@ -52,8 +52,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/decryptAsymmetric.js b/kms/decryptAsymmetric.js
index ba96281367..d7bf5134e3 100644
--- a/kms/decryptAsymmetric.js
+++ b/kms/decryptAsymmetric.js
@@ -89,8 +89,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/decryptSymmetric.js b/kms/decryptSymmetric.js
index 0401ed0351..0291717ab2 100644
--- a/kms/decryptSymmetric.js
+++ b/kms/decryptSymmetric.js
@@ -75,8 +75,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/destroyKeyVersion.js b/kms/destroyKeyVersion.js
index b5511cc258..0a6571325b 100644
--- a/kms/destroyKeyVersion.js
+++ b/kms/destroyKeyVersion.js
@@ -60,8 +60,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/disableKeyVersion.js b/kms/disableKeyVersion.js
index 976094c660..a16db8e2c4 100644
--- a/kms/disableKeyVersion.js
+++ b/kms/disableKeyVersion.js
@@ -66,8 +66,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/enableKeyVersion.js b/kms/enableKeyVersion.js
index d73ade3e4f..dec512b380 100644
--- a/kms/enableKeyVersion.js
+++ b/kms/enableKeyVersion.js
@@ -66,8 +66,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/encryptAsymmetric.js b/kms/encryptAsymmetric.js
index 45fd2c5d6a..bea1311c93 100644
--- a/kms/encryptAsymmetric.js
+++ b/kms/encryptAsymmetric.js
@@ -93,8 +93,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/encryptSymmetric.js b/kms/encryptSymmetric.js
index 9158b04b8a..283492b111 100644
--- a/kms/encryptSymmetric.js
+++ b/kms/encryptSymmetric.js
@@ -77,8 +77,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/generateRandomBytes.js b/kms/generateRandomBytes.js
new file mode 100644
index 0000000000..6f0dc17f58
--- /dev/null
+++ b/kms/generateRandomBytes.js
@@ -0,0 +1,65 @@
+// Copyright 2021 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+'use strict';
+
+async function main(
+  projectId = 'my-project',
+  locationId = 'us-east1',
+  numBytes = 256
+) {
+  // [START kms_generate_random_bytes]
+  //
+  // TODO(developer): Uncomment these variables before running the sample.
+  //
+  // const projectId = 'my-project';
+  // const locationId = 'us-east1';
+  // const numBytes = 256;
+
+  // Imports the Cloud KMS library
+  const {KeyManagementServiceClient} = require('@google-cloud/kms');
+
+  // Instantiates a client
+  const client = new KeyManagementServiceClient();
+
+  // Build the location name
+  const locationName = client.locationPath(projectId, locationId);
+
+  async function generateRandomBytes() {
+    const [randomBytesResponse] = await client.generateRandomBytes({
+      location: locationName,
+      lengthBytes: numBytes,
+      protectionLevel: 'HSM',
+    });
+
+    console.log(`Random bytes: ${randomBytesResponse.data.toString('base64')}`);
+    return randomBytesResponse;
+  }
+
+  return generateRandomBytes();
+  // [END kms_generate_random_bytes]
+}
+module.exports.main = main;
+
+/* c8 ignore next 10 */
+if (require.main === module) {
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+}
diff --git a/kms/getKeyLabels.js b/kms/getKeyLabels.js
index 728b124e2c..bee79d4833 100644
--- a/kms/getKeyLabels.js
+++ b/kms/getKeyLabels.js
@@ -55,8 +55,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/getKeyVersionAttestation.js b/kms/getKeyVersionAttestation.js
index dbd621e6b5..4674873e43 100644
--- a/kms/getKeyVersionAttestation.js
+++ b/kms/getKeyVersionAttestation.js
@@ -67,8 +67,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/getPublicKey.js b/kms/getPublicKey.js
index d70a337de8..f47a9f7803 100644
--- a/kms/getPublicKey.js
+++ b/kms/getPublicKey.js
@@ -71,8 +71,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/iamAddMember.js b/kms/iamAddMember.js
index 4010167c0a..7ab63acddf 100644
--- a/kms/iamAddMember.js
+++ b/kms/iamAddMember.js
@@ -75,8 +75,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/iamGetPolicy.js b/kms/iamGetPolicy.js
index c28bd3e2ea..bccabc8042 100644
--- a/kms/iamGetPolicy.js
+++ b/kms/iamGetPolicy.js
@@ -67,8 +67,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/iamRemoveMember.js b/kms/iamRemoveMember.js
index b920ef7954..2f6f2cd9e9 100644
--- a/kms/iamRemoveMember.js
+++ b/kms/iamRemoveMember.js
@@ -82,8 +82,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/quickstart.js b/kms/quickstart.js
index 503a8dcddf..9253bd221d 100644
--- a/kms/quickstart.js
+++ b/kms/quickstart.js
@@ -48,8 +48,14 @@ async function main(projectId = 'my-project', locationId = 'us-east1') {
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/restoreKeyVersion.js b/kms/restoreKeyVersion.js
index e2121f6d63..f4366a0d7c 100644
--- a/kms/restoreKeyVersion.js
+++ b/kms/restoreKeyVersion.js
@@ -60,8 +60,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/signAsymmetric.js b/kms/signAsymmetric.js
index 08b40d9df5..3b6dd0aa5b 100644
--- a/kms/signAsymmetric.js
+++ b/kms/signAsymmetric.js
@@ -101,8 +101,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/signMac.js b/kms/signMac.js
new file mode 100644
index 0000000000..69a800b817
--- /dev/null
+++ b/kms/signMac.js
@@ -0,0 +1,82 @@
+// Copyright 2021 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+'use strict';
+
+async function main(
+  projectId = 'your-project-id',
+  locationId = 'us-east1',
+  keyRingId = 'my-key-ring',
+  keyId = 'my-key',
+  versionId = '123',
+  data = Buffer.from('...')
+) {
+  // [START kms_sign_mac]
+  //
+  // TODO(developer): Uncomment these variables before running the sample.
+  //
+  // const projectId = 'your-project-id';
+  // const locationId = 'us-east1';
+  // const keyRingId = 'my-key-ring';
+  // const keyId = 'my-key';
+  // const versionId = '123';
+  // const data = Buffer.from('...');
+
+  // Imports the Cloud KMS library
+  const {KeyManagementServiceClient} = require('@google-cloud/kms');
+
+  // Instantiates a client
+  const client = new KeyManagementServiceClient();
+
+  // Build the version name
+  const versionName = client.cryptoKeyVersionPath(
+    projectId,
+    locationId,
+    keyRingId,
+    keyId,
+    versionId
+  );
+
+  async function signMac() {
+    // Sign the data with Cloud KMS
+    const [signResponse] = await client.macSign({
+      name: versionName,
+      data: data,
+    });
+
+    // Example of how to display signature. Because the signature is in a binary
+    // format, you need to encode the output before printing it to a console or
+    // displaying it on a screen.
+    const encoded = signResponse.mac.toString('base64');
+    console.log(`Signature: ${encoded}`);
+
+    return signResponse;
+  }
+
+  return signMac();
+  // [END kms_sign_mac]
+}
+module.exports.main = main;
+
+/* c8 ignore next 10 */
+if (require.main === module) {
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+}
diff --git a/kms/test/kms.test.js b/kms/test/kms.test.js
index 5bda07cc7e..57eeb776a7 100644
--- a/kms/test/kms.test.js
+++ b/kms/test/kms.test.js
@@ -30,6 +30,7 @@ const asymmetricSignEcKeyId = v4();
 const asymmetricSignRsaKeyId = v4();
 const hsmKeyId = v4();
 const symmetricKeyId = v4();
+const hmacKeyId = v4();
 
 const nodeMajorVersion = parseInt(process.version.match(/v?(\d+).*/)[1]);
 
@@ -181,6 +182,31 @@ describe('Cloud KMS samples', () => {
       ),
       'ENABLED'
     );
+
+    await client.createCryptoKey({
+      parent: client.keyRingPath(projectId, locationId, keyRingId),
+      cryptoKeyId: hmacKeyId,
+      cryptoKey: {
+        purpose: 'MAC',
+        versionTemplate: {
+          algorithm: 'HMAC_SHA256',
+        },
+        labels: {
+          foo: 'bar',
+          zip: 'zap',
+        },
+      },
+    });
+    await waitForState(
+      client.cryptoKeyVersionPath(
+        projectId,
+        locationId,
+        keyRingId,
+        hmacKeyId,
+        1
+      ),
+      'ENABLED'
+    );
   });
 
   beforeEach(async () => {
@@ -255,6 +281,13 @@ describe('Cloud KMS samples', () => {
     assert.equal(key.labels.cost_center, 'cc1234');
   });
 
+  it('creates mac keys', async () => {
+    const sample = require('../createKeyMac');
+    const key = await sample.main(projectId, locationId, keyRingId, v4());
+    assert.equal(key.purpose, 'MAC');
+    assert.equal(key.versionTemplate.algorithm, 'HMAC_SHA256');
+  });
+
   it('creates key rings', async () => {
     const sample = require('../createKeyRing');
     const keyRing = await sample.main(projectId, locationId, v4());
@@ -452,6 +485,12 @@ describe('Cloud KMS samples', () => {
     assert.equal(decryptResponse.plaintext.toString('utf8'), plaintext);
   });
 
+  it('generates random bytes', async () => {
+    const sample = require('../generateRandomBytes');
+    const result = await sample.main(projectId, locationId, 256);
+    assert.equal(result.data.length, 256);
+  });
+
   it('gets keys with labels', async () => {
     const sample = require('../getKeyLabels');
     const key = await sample.main(
@@ -626,6 +665,34 @@ describe('Cloud KMS samples', () => {
     assert.isTrue(verified);
   });
 
+  it('signs with mac keys', async () => {
+    const data = 'my data';
+
+    const sample = require('../signMac');
+    const result = await sample.main(
+      projectId,
+      locationId,
+      keyRingId,
+      hmacKeyId,
+      1,
+      Buffer.from(data)
+    );
+
+    const [verifyResponse] = await client.macVerify({
+      name: client.cryptoKeyVersionPath(
+        projectId,
+        locationId,
+        keyRingId,
+        hmacKeyId,
+        1
+      ),
+      data: Buffer.from(data),
+      mac: result.mac,
+    });
+
+    assert.isTrue(verifyResponse.success);
+  });
+
   it('adds rotation schedules', async () => {
     const sample = require('../updateKeyAddRotation');
     const key = await sample.main(
@@ -757,4 +824,32 @@ describe('Cloud KMS samples', () => {
 
     assert.isTrue(verified);
   });
+
+  it('verifies with mac keys', async () => {
+    const data = 'my data';
+
+    const [signResponse] = await client.macSign({
+      name: client.cryptoKeyVersionPath(
+        projectId,
+        locationId,
+        keyRingId,
+        hmacKeyId,
+        1
+      ),
+      data: Buffer.from(data),
+    });
+
+    const sample = require('../verifyMac');
+    const result = await sample.main(
+      projectId,
+      locationId,
+      keyRingId,
+      hmacKeyId,
+      1,
+      Buffer.from(data),
+      signResponse.mac
+    );
+
+    assert.isTrue(result.success);
+  });
 });
diff --git a/kms/updateKeyAddRotation.js b/kms/updateKeyAddRotation.js
index d00bca8dac..634675bc31 100644
--- a/kms/updateKeyAddRotation.js
+++ b/kms/updateKeyAddRotation.js
@@ -68,8 +68,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/updateKeyRemoveLabels.js b/kms/updateKeyRemoveLabels.js
index 6981ea1322..bef2b533cf 100644
--- a/kms/updateKeyRemoveLabels.js
+++ b/kms/updateKeyRemoveLabels.js
@@ -59,8 +59,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/updateKeyRemoveRotation.js b/kms/updateKeyRemoveRotation.js
index fcd5ae8210..2e355f06c4 100644
--- a/kms/updateKeyRemoveRotation.js
+++ b/kms/updateKeyRemoveRotation.js
@@ -59,8 +59,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/updateKeySetPrimary.js b/kms/updateKeySetPrimary.js
index 5da1768dc6..046de0b24b 100644
--- a/kms/updateKeySetPrimary.js
+++ b/kms/updateKeySetPrimary.js
@@ -55,8 +55,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/updateKeyUpdateLabels.js b/kms/updateKeyUpdateLabels.js
index 2325994df3..d23ef89500 100644
--- a/kms/updateKeyUpdateLabels.js
+++ b/kms/updateKeyUpdateLabels.js
@@ -61,8 +61,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/verifyAsymmetricEc.js b/kms/verifyAsymmetricEc.js
index 71b6b1ae49..ce0c3997cf 100644
--- a/kms/verifyAsymmetricEc.js
+++ b/kms/verifyAsymmetricEc.js
@@ -77,8 +77,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/verifyAsymmetricRsa.js b/kms/verifyAsymmetricRsa.js
index 7fef55e94d..d380355c42 100644
--- a/kms/verifyAsymmetricRsa.js
+++ b/kms/verifyAsymmetricRsa.js
@@ -78,8 +78,14 @@ async function main(
 }
 module.exports.main = main;
 
-/* c8 ignore next 4 */
+/* c8 ignore next 10 */
 if (require.main === module) {
-  const args = process.argv.slice(2);
-  main(...args).catch(console.error);
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
 }
diff --git a/kms/verifyMac.js b/kms/verifyMac.js
new file mode 100644
index 0000000000..fa880d493c
--- /dev/null
+++ b/kms/verifyMac.js
@@ -0,0 +1,80 @@
+// Copyright 2021 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+'use strict';
+
+async function main(
+  projectId = 'your-project-id',
+  locationId = 'us-east1',
+  keyRingId = 'my-key-ring',
+  keyId = 'my-key',
+  versionId = '123',
+  data = Buffer.from('...'),
+  signature = Buffer.from('...')
+) {
+  // [START kms_verify_mac]
+  //
+  // TODO(developer): Uncomment these variables before running the sample.
+  //
+  // const projectId = 'your-project-id';
+  // const locationId = 'us-east1';
+  // const keyRingId = 'my-key-ring';
+  // const keyId = 'my-key';
+  // const versionId = '123';
+  // const data = Buffer.from('...');
+  // const signature = Buffer.from('...');
+
+  // Imports the Cloud KMS library
+  const {KeyManagementServiceClient} = require('@google-cloud/kms');
+
+  // Instantiates a client
+  const client = new KeyManagementServiceClient();
+
+  // Build the version name
+  const versionName = client.cryptoKeyVersionPath(
+    projectId,
+    locationId,
+    keyRingId,
+    keyId,
+    versionId
+  );
+
+  async function verifyMac() {
+    // Verify the data with Cloud KMS
+    const [verifyResponse] = await client.macVerify({
+      name: versionName,
+      data: data,
+      mac: signature,
+    });
+
+    console.log(`Verified: ${verifyResponse.success}`);
+    return verifyResponse;
+  }
+
+  return verifyMac();
+  // [END kms_verify_mac]
+}
+module.exports.main = main;
+
+/* c8 ignore next 10 */
+if (require.main === module) {
+  main(...process.argv.slice(2)).catch(err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+  process.on('unhandledRejection', err => {
+    console.error(err.message);
+    process.exitCode = 1;
+  });
+}