Understanding Google Cloud Key Management Service (KMS) and Its Importance in Data Security

Google Cloud Platform offers a Key Management Service (KMS) to create and manage encryption keys quickly. Many industries, like financial institutions and healthcare centers, are sensitive to storing and securing their data and are targeting google with this service. 

What is the Google Cloud Key Management Service (KMS)?

Google Cloud Key Management Service is a cloud service that manages encryption keys for other cloud services.  

The Google Cloud KMS platform enables users to manage cryptographic keys for direct use or use by other cloud applications and resources. It is a rest API that decrypts and encrypts the data as the secrets of storing data.

How Does Google Cloud Key Management Service Work?

  • Google Cloud KMS stores AES-256 encryption keys in a five-level hierarchy, with the top level being the GCP Project. 

  • KeyRings hold groups of CryptoKeys with similar permission levels, and CryptoKeyVersions are the final tier. 

  • The REST API allows for listing, creating, destroying, and updating keys, encrypting and decrypting data using specific keys, and setting IAM policies. 

  • Key destruction has a 24-hour delay, and previous key versions can be restored.

What Are the Main Use Cases of Google KMS?

  1. 1

    Support Regulatory Compliance

    Google Cloud Key Management Service supports compliance with Cloud EKM and CloudHSM which are used for specific key management technologies. 

  2. 2

    Data Encryption for Storage or in Transit

    Cloud KMS can be used to encrypt data stored in databases, file systems, or other data storage systems, as well as data transmitted over networks.

  3. 3

    Multi-cloud Security

    KMS can manage keys across different cloud platforms, allowing organizations to control their encryption keys even if their data is stored in multiple cloud environments.

What Are the Key Features of Google Key Management Service?

  • Managing Encryption Keys

    A cloud-based key management service allows you to manage symmetric and asymmetric cryptographic keys for your cloud services as you would on-premises.

    You can create, use, rotate, and delete AES256, RSA 2048, RSA 3072, RSA 4096, EC P256, and EC P384 cryptographic keys, giving you centralized management of encryption keys.

  • Hardware Key Security

    Hardware key security is provided through a fully managed service that allows you to switch between software- and hardware-protected encryption keys easily.

    FIPS 140-2 Level 3 validated HSMs host encryption keys and performed cryptographic operations. This eliminates your need to manage an HSM cluster and protects your most sensitive workloads.

  • Offers Support for External Key Managers

    You can encrypt data in BigQuery and Compute Engine with encryption keys stored and managed in a third-party key management system deployed outside Google's infrastructure.

    The External Key Manager maintains a separation between your data at rest and your encryption keys while still leveraging the power of the cloud for computing and analytics.

What are the 5 Pillars Supported by Google KMS?

  1. 1

    Customer Control

    It allows users to manage both software and hardware encryption keys or use their own keys for added flexibility and control.

  2. 2

    Access Control and Monitoring

    With Cloud KMS, users can manage permissions on individual keys and monitor their applications for any unusual activity.

  3. 3


    Cloud KMS also offers regionalization, with the KMS service configured to create, store, and process software keys only in the Google Cloud region selected by the user. 

  4. 4


    It periodically scans and backs up all key material and metadata to guard against data corruption and verify successful decryption.

  5. 5


    Cloud KMS is designed with strong security measures to prevent unauthorized key access. It is fully integrated with Identity and Access Management (IAM) and Cloud Audit Logs controls for added protection.

Understanding Google KMS Pricing: How Much Does it Charge? 

Cloud KMS pricing is based on the usage rate for key operations, the number of active keys, and the protection level on the key version. Google Key Management Service charges users based on the products:

  • Cloud Key Management Services

  • Cloud External Key Manager

  • Cloud HSM

Let’s look at its pricing:

Google KMS


Active Cryptographic Operations

$0.03 per 10,000 operations

Key Storage

$0.06 per month per key version

HSM-Protected Keys

$1.00 per HSM-protected key version per month

HSM-Protected Key Operations

$0.03 per operation

IAM Permission for Keys


Key Deletion


Key Rotation


Key Usage Audit Logs


What Are the Benefits and Limitations of Google KMS?


  • Easy to Use

    Google KMS is easy to set up and use, with a simple user interface and integration with other Google Cloud services.

  • Flexible 

    It provides customers with the flexibility to manage their encryption keys either in the cloud or on-premises.

  • Secure

    Google KMS is designed with strong security measures to prevent unauthorized key access. It is fully integrated with Identity and Access Management (IAM) and Cloud Audit Logs controls for added protection.

  • Scalable

    Google KMS is designed to be highly scalable, with the ability to handle large volumes of cryptographic operations.


  • Complexity

    While Google KMS is easy to use, it can be complex to set up and configure for more complex environments.

  • Cost

    Google KMS is not a low-cost service, and charges for active cryptographic operations, key storage, and HSM-protected keys can add up quickly.

  • Limited Key Types

    It supports only a limited number of key types, which may not be suitable for all use cases.

  • Limited Key Size

    It has a maximum key size limit, which may not be sufficient for customers with specific cryptographic requirements.

How Does Google Key Management Integrate with Other Cloud Services?

The following are the steps of integrating Google Key Management with other Cloud services: 

  1. 1

    First, you need to enable the Key Management Service API on your Google Cloud Platform (GCP) project. This can be done by going to the API Manager in the GCP Console and selecting "Enable API" for KMS.

  2. 2

    Next, you will need to create a Key Ring, which is a container for your cryptographic keys. You can create a Key Ring by selecting "Create Key Ring" in the KMS section of the GCP Console.

  3. 3

    Create a Key within it. You can do this by selecting "Create Key" in the KMS section of the GCP Console.

  4. 4

    You can now grant access to the Key to the cloud service you want to use it with. This can be done by adding the service account of the cloud service to the IAM policy of the Key.

  5. 5

    Finally, you can use the Key to encrypt and decrypt data within the cloud service. To do this, you will need to use the KMS API to access the Key and perform cryptographic operations.

How to Enable Cloud KMS API for the Google Cloud Project?

Let’s look at enabling Cloud KMS API for the Google Cloud project:

  1. 1

    Go to the Google Cloud console API Library.

  2. 2

    Select the project you want to use from the projects list.

  3. 3

    In the navigation menu, select APIs & Services > Dashboard.

  4. 4

    Click on the "+ ENABLE APIS AND SERVICES" button.

  5. 5

    Search for "Cloud KMS API" in the search bar and click on it.

  6. 6

    Click on the "ENABLE" button to enable the API.

How to Troubleshoot Common Issues When Using Google KMS?

  • Permissions Errors

    If you are unable to access a key or perform an operation due to permissions errors, you should ensure that you have the necessary IAM roles and permissions. 

  • Incorrectly Configured Encryption Libraries

    If you use the Google Cloud client libraries for encryption, ensure you have correctly configured the client with the appropriate credentials and options.

  • Firewall Issues

    If you are having trouble connecting to Cloud KMS from your application, ensure your firewall rules are correctly configured to allow traffic to and from the Cloud KMS service. 

Best Practices on How to Use Google KMS for Maximum Data Security

  • Create Separate Key Ring for Every Project

    Creating a separate key ring will allow you to manage and control access to the keys. It’ll make the process to audit key access easier for you. It's important, especially when you deal with sensitive data.

  • Give Access Only on Need-to-know Basis

    Cloud KMS can be used to encrypt and decrypt data. So, it’s necessary to ensure that only authorized users can access it. 

  • Use Customer-Managed Encryption Keys

    They can let you manage and control rather than Google. That way, only you can access the key material stored in a cloud service or secure hardware device. 

  • Set Up Audit Log Sink

    Lets you track activities occurring within the Google Key Management Service environment. It includes the changes made to any resources like keys and key versions.


Google Key Management Service is a powerful tool for managing cryptographic keys and secrets in the cloud.

By leveraging KMS, organizations can ensure their data is encrypted and secure, meeting compliance requirements and maintaining security best practices in the cloud. 

About the author


Youssef is a Senior Cloud Consultant & Founder of ITCertificate.org

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