About keys

Azure Key Vault provides two types of resources to store and manage cryptographic keys. Vaults support software-protected and HSM-protected (Hardware Security Module) keys. Managed HSMs only support HSM-protected keys.

Resource type Key protection methods Data-plane endpoint base URL
Vaults Software-protected

and

HSM-protected (with Premium SKU)
https://{vault-name}.vault.azure.net
Managed HSMs HSM-protected https://{hsm-name}.managedhsm.azure.net
  • Vaults - Vaults provide a low-cost, easy to deploy, multi-tenant, zone-resilient (where available), highly available key management solution suitable for most common cloud application scenarios.
  • Managed HSMs - Managed HSM provides single-tenant, zone-resilient (where available), highly available HSMs to store and manage your cryptographic keys. Most suitable for applications and usage scenarios that handle high value keys. Also helps to meet most stringent security, compliance, and regulatory requirements.

Note

Vaults also allow you to store and manage several types of objects like secrets, certificates and storage account keys, in addition to cryptographic keys.

Cryptographic keys in Key Vault are represented as JSON Web Key [JWK] objects. The JavaScript Object Notation (JSON) and JavaScript Object Signing and Encryption (JOSE) specifications are:

The base JWK/JWA specifications are also extended to enable key types unique to the Azure Key Vault and Managed HSM implementations.

HSM-protected keys (also referred to as HSM-keys) are processed in an HSM (Hardware Security Module) and always remain HSM protection boundary.

  • Vaults use FIPS 140-2 Level 2 validated HSMs to protect HSM-keys in shared HSM backend infrastructure.
  • Managed HSM uses FIPS 140-2 Level 3 validated HSM modules to protect your keys. Each HSM pool is an isolated single-tenant instance with its own security domain providing complete cryptographic isolation from all other HSMs sharing the same hardware infrastructure.

These keys are protected in single-tenant HSM-pools. You can import an RSA, EC, and symmetric key, in soft form or by exporting from a supported HSM device. You can also generate keys in HSM pools. When you import HSM keys using the method described in the BYOK (bring your own key) specification, it enables secure transportation key material into Managed HSM pools.

For more information on geographical boundaries, see Microsoft Azure Trust Center

Key types and protection methods

Key Vault supports RSA and EC keys. Managed HSM supports RSA, EC, and symmetric keys.

HSM-protected keys

Key type Vaults (Premium SKU only) Managed HSMs
EC-HSM: Elliptic Curve key Supported Supported
RSA-HSM: RSA key Supported Supported
oct-HSM: Symmetric key Not supported Supported

Software-protected keys

Key type Vaults Managed HSMs
RSA: "Software-protected" RSA key Supported Not supported
EC: "Software-protected" Elliptic Curve key Supported Not supported

Compliance

Key type and destination Compliance
Software-protected keys in vaults (Premium & Standard SKUs) FIPS 140-2 Level 1
HSM-protected keys in vaults (Premium SKU) FIPS 140-2 Level 2
HSM-protected keys in Managed HSM FIPS 140-2 Level 3

See Key types, algorithms, and operations for details about each key type, algorithms, operations, attributes, and tags.

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