Silo key management is the practice of managing encryption keys inside each cloud provider’s own native key management service, so keys, policies, and audit logs stay separated per cloud environment.
Silo key management uses a cloud service provider’s own key management service, such as AWS KMS, Azure Key Vault, or Google Cloud KMS, to create and control encryption keys within that single cloud. Each cloud is a separate silo with its own console, policies, rotation schedule, and logs. It is the simplest cloud key model and the default starting point.
Key Takeaways
- Native KMS keys can be HSM-backed to FIPS 140-2 or FIPS 140-3 and can be strengthened with BYOK, but the silo boundary still limits cross-cloud visibility.
- Silo key management means managing encryption keys inside each cloud provider’s native KMS, separately from every other cloud or on-premises environment.
- The three major native services are AWS KMS, Azure Key Vault, and Google Cloud KMS, each with its own interface, policies, and audit trail.
- The model is fast to adopt and needs no extra tooling, but it produces key sprawl and inconsistent governance once an organization runs more than one cloud.
- Centralized or holistic key management breaks down the silos by managing keys across all clouds and on-premises from one platform.
How Silo Key Management Works
Silo key management works by keeping every stage of the key lifecycle inside the cloud provider that hosts the data.
When you encrypt data in a cloud service, the provider’s native KMS generates a key, stores it, controls access to it, and logs its use, all within that provider’s boundary. A key created in AWS KMS cannot be seen or managed from the Azure or Google consoles, and the reverse is also true. Each silo runs independently.
A typical silo setup follows this pattern:
- Create the key in the native KMS: You provision a key in AWS KMS, Azure Key Vault, or Google Cloud KMS through that provider’s console or API.
- Set access policy: You attach identity and access rules so only authorized principals in that cloud can use the key.
- Encrypt data in place: Cloud services in that provider call the KMS to encrypt and decrypt data, often through envelope encryption where the KMS key wraps a data encryption key.
- Rotate on a per-cloud schedule: Each provider runs its own rotation schedule and its own logging, independent of the others.
- Audit within the silo: Key usage records live in that provider’s audit log, for example AWS CloudTrail or Azure Monitor, and are not aggregated across clouds.
Native Key Management Services by Provider
Each major cloud provider ships its own native key management service, and silo key management uses these services directly.
| Cloud Provider | Native KMS | HSM Backing |
| Amazon Web Services | AWS KMS (with CloudHSM option) | FIPS 140-3 Level 3 validated HSMs |
| Microsoft Azure | Azure Key Vault (Premium and Managed HSM) | FIPS 140-3 Level 3 validated HSMs |
| Google Cloud | Google Cloud KMS (with Cloud HSM) | FIPS 140-2 Level 3 validated HSMs |
In Azure Key Vault and Google Cloud KMS, selecting the HSM-backed tier or protection level is what makes a key eligible for FIPS 140 hardware backing. AWS KMS protects every key with FIPS 140-3 validated HSMs by default. The provider validates the hardware module; you remain responsible for configuring access control, rotation, and logging correctly inside each silo.
Silo vs Centralized (Holistic) Key Management
Silo key management keeps keys inside each cloud provider’s KMS, while centralized key management uses one platform to manage keys across every cloud and on-premises environment.
| Attribute | Silo Key Management | Centralized Key Management |
| Where keys live | Inside each cloud provider’s native KMS | One platform spanning all clouds and on-premises |
| Consoles to learn | One per cloud provider | A single interface |
| Policy consistency | Set separately per silo | One policy set applied everywhere |
| Visibility | Per-cloud only; no single view | One view across all environments |
| Setup effort | Lowest; uses services already present | Higher; requires a dedicated platform |
| Best for | Single-cloud or early cloud adoption | Multi-cloud, hybrid, and large key estates |
The traditional approach of managing keys in separate silos delivers diminishing returns as the number of keys grows. Centralized key management was introduced to break down those silos, reduce the time spent managing keys, and apply consistent policy wherever data is kept. The choice is a trade between simplicity now and governance at scale.
When Silo Key Management Makes Sense, and When It Does Not
Silo key management is the right choice when an organization operates in a single cloud and wants the fastest, lowest-effort path to encryption.
It fits early cloud adoption, small key estates, and workloads that never leave one provider. There is nothing extra to buy or deploy, because the native KMS is already part of the cloud account.
The model becomes a liability once an organization runs more than one cloud. Keys sprawl across separate consoles, rotation schedules drift, and there is no single view of where keys live or whether they meet policy. A missed rotation or a misconfigured policy in one silo can cause an outage or a compliance gap that no one notices until an audit.
At that point, a centralized or holistic model, often built on BYOK and an external key manager, gives back the visibility and consistent governance that the silo model gives up.
How Encryption Consulting Helps
Cloud Data Protection Services from Encryption Consulting help you decide when silo key management is enough and when to move to a centralized model. Our consultants assess your cloud estate, design key policies that stay consistent across AWS, Azure, and Google Cloud, and implement BYOK and external key management where the silo model no longer scales. Encryption Consulting’s HSM-as-a-Service then provides FIPS 140-backed key storage under your control. Backed by ISO/IEC 27001:2022 and SOC 2 certified practices.
Frequently Asked Questions
What is silo key management in simple terms?
Silo key management means you manage encryption keys inside each cloud provider’s own key management service, separately from every other environment. Keys created in AWS KMS stay in AWS, keys in Azure Key Vault stay in Azure, and keys in Google Cloud KMS stay in Google Cloud. Each cloud is its own silo with its own console, policies, and audit logs.
What is the difference between silo and centralized key management?
Silo key management keeps keys inside each cloud provider’s native KMS, so a team running three clouds manages three separate key stores. Centralized (or holistic) key management uses one platform to manage keys across all clouds and on-premises from a single console. Centralized management reduces key sprawl and enforces one policy set, while silo management is simpler to start but harder to govern at scale.
When should you use silo key management?
Silo key management fits organizations that run in a single cloud, have a small number of keys, or want the fastest path to encryption using native services like AWS KMS or Azure Key Vault. It works well for early-stage cloud adoption and workloads that never leave one provider. Once you run multiple clouds or need consistent audit and rotation policies, a centralized model usually serves better.
What are the main risks of silo key management?
The main risks are key sprawl and inconsistent governance. Because each cloud silo has its own console, policies, and rotation schedule, keys can drift out of policy, expire unnoticed, or escape audit. Teams must learn every provider’s interface separately, and there is no single view of where keys live. A missed rotation or a misconfigured policy in one silo can cause an outage or a compliance gap.
How does silo key management relate to BYOK?
In pure silo key management the cloud provider generates and holds the keys inside its own KMS. Bring Your Own Key (BYOK) is a step up in control: the customer generates key material externally, often in an on-premises HSM, then imports it into the provider’s KMS. BYOK can be used inside a silo model to strengthen key ownership, but it does not by itself unify management across clouds.
Is silo key management FIPS 140 compliant?
It can be. Native cloud key management services back keys with hardware security modules validated to FIPS 140-2 or the current FIPS 140-3 standard, such as AWS KMS, Azure Key Vault, and Google Cloud KMS with HSM protection. Compliance depends on using HSM-protected keys (automatic in AWS KMS, a tier choice in Azure and Google Cloud) and configuring rotation, access control, and logging correctly in each silo, since the provider validates the module, not your configuration.
Take Control of Your Cloud Keys
Ready to move beyond scattered cloud silos? Protect your data in the cloud with Encryption Consulting, or talk to an Encryption Consulting advisor.