Customer-Managed Keys vs. Cloud Provider-Managed Keys
2023-December-13 • by Platformers
In the age of cloud computing, data security is paramount. With the vast amount of sensitive information being stored in the cloud, organizations must take a proactive approach to protect their assets. A crucial aspect of cloud security is encryption, and one of the key decisions you'll face is whether to use customer-managed keys (CMKs) or cloud provider-managed keys (CPMKs) to safeguard your data. In this article, we'll dive into the differences between these two approaches and discuss their respective security implications.
Understanding CMKs and CPMKs
Customer-Managed Keys (CMKs): CMKs put the control and responsibility for encryption keys squarely in the hands of the customer. When you opt for CMKs, you generate, store, and manage your encryption keys. This level of control can be a double-edged sword, offering security benefits when managed diligently but posing risks if mishandled.
Cloud Provider-Managed Keys (CPMKs): CPMKs, as the name suggests, are managed by the cloud provider, such as Amazon Web Services (AWS managed keys), Microsoft Azure (Microsoft-managed keys), or Google Cloud (Google-managed encryption keys). In this scenario, the provider takes care of key generation, storage, and management. While it offers convenience, it also means entrusting the provider with key security.
Key Considerations for Security
1. Control and Ownership
CMKs: With CMKs, you have complete control and ownership of your encryption keys. This means you decide when and how keys are rotated, who has access to them, and how they are stored.
CPMKs: Cloud providers take charge of key management with CPMKs. This simplifies the process but may reduce your direct control over key management decisions.
2. Key Management
CMKs: Managing your own keys gives you the flexibility to implement robust security practices tailored to your organization's needs. However, it also means taking on the responsibility of securely storing and rotating keys.
CPMKs: Cloud providers invest heavily in secure key management infrastructure, including Hardware Security Modules (HSMs). They handle the complexities of key management, but you must trust the provider's security measures.
3. Compliance and Auditing
CMKs: If your organization has specific compliance requirements, CMKs can offer more granular control over compliance and auditing because you maintain visibility and control over key management.
CPMKs: Providers offer compliance and auditing reports, but you have less control over specific compliance when using CPMKs.
4. Risk of Key Exposure
CMKs: Mismanagement or unauthorized access to CMKs can result in key exposure. Organizations must invest in robust key management practices to mitigate this risk.
CPMKs: Providers like AWS, Azure, and Google Cloud have stringent security measures to protect CPMKs. However, in the unlikely event of a breach or compromise of their systems, CPMKs could be exposed.
My Opinion
In my opinion, CPMKs are often more secure for several reasons. Firstly, cloud providers have dedicated teams and resources to ensure the security of their key management systems. They are more likely to adhere to industry best practices and standards when it comes to key security.
Secondly, CPMKs are typically rotated on a regular basis as part of the cloud provider's security protocols. In my experience, CMKs are not always rotated as frequently or consistently by organizations, which can leave them vulnerable to attacks targeting older keys.
Another factor to consider is the human factor. Take key storage, for example with CMKs, organizations are responsible for securely storing their keys. This introduces the risk of human error, such as accidental exposure (e.g., someone uploading the key to Git) or accidental deletion of keys. CPMKs, on the other hand, benefit from the cloud provider's expertise in secure key storage. An overlooked factor, the cost of having your engineers now have to manually rotate keys, sounds simple but depending on the number of keys you have could take longer than you expect and with your rotation schedule you have to do that every 3, 6, 12 months whatever you set. Because this aspect is often overlooked, organizations may establish a key rotation policy of, let's say, every 3 months, but engineers may be busy and "get to it next sprint" and then it keeps getting delayed.
Lastly, cloud providers often tout their compliance certifications, such as HIPAA, PCI DSS, SOC, ISO and GDPR, which can streamline compliance efforts for organizations in regulated industries. Leveraging CPMKs can simplify the path to meeting these stringent requirements. If you have CMKs, now you have to have processes and technology in place to meet those compliance levels.
In conclusion, while the choice between CMKs and CPMKs ultimately depends on your organization's specific needs and security posture, CPMKs offer compelling advantages in terms of security, key rotation, and compliance, making them a strong contender for many cloud security scenarios.