Azure Key Vault keys, secrets and certificates overview

Azure Key Vault enables Microsoft Azure applications and users to store and use several types of secret/key data. Key Vault resource provider supports two resource types: vaults and managed HSMs.

DNS suffixes for base URL

The table below shows the base URL DNS suffix used by the data-plane endpoint for vaults and managed HSM pools in various cloud environments.

Cloud environment DNS suffix for vaults DNS suffix for managed HSMs
Azure Cloud
Azure China Cloud Not supported
Azure US Government Not supported
Azure German Cloud Not supported

Object types

The table below shows object types and their suffixes in the base URL.

Object type URL Suffix Vaults Managed HSM Pools
HSM-protected keys /keys Supported Supported
Software-protected keys /keys Supported Not supported
Secrets /secrets Supported Not supported
Certificates /certificates Supported Not supported
Storage account keys /storage Supported Not supported
  • Cryptographic keys: Supports multiple key types and algorithms, and enables the use of software-protected and HSM-protected keys. For more information, see About keys.
  • Secrets: Provides secure storage of secrets, such as passwords and database connection strings. For more information, see About secrets.
  • Certificates: Supports certificates, which are built on top of keys and secrets and add an automated renewal feature. Keep in mind when a certificate is created, an addressable key and secret are also created with the same name. For more information, see About certificates.
  • Azure Storage account keys: Can manage keys of an Azure Storage account for you. Internally, Key Vault can list (sync) keys with an Azure Storage Account, and regenerate (rotate) the keys periodically. For more information, see Manage storage account keys with Key Vault.

For more general information about Key Vault, see About Azure Key Vault. For more information about Managed HSM pools, see What is Azure Key Vault Managed HSM?

Data types

Refer to the JOSE specifications for relevant data types for keys, encryption, and signing.

  • algorithm - a supported algorithm for a key operation, for example, RSA1_5
  • ciphertext-value - cipher text octets, encoded using Base64URL
  • digest-value - the output of a hash algorithm, encoded using Base64URL
  • key-type - one of the supported key types, for example RSA (Rivest-Shamir-Adleman).
  • plaintext-value - plaintext octets, encoded using Base64URL
  • signature-value - output of a signature algorithm, encoded using Base64URL
  • base64URL - a Base64URL [RFC4648] encoded binary value
  • boolean - either true or false
  • Identity - an identity from Azure Active Directory (AAD).
  • IntDate - a JSON decimal value representing the number of seconds from 1970-01-01T0:0:0Z UTC until the specified UTC date/time. See RFC3339 for details regarding date/times, in general and UTC in particular.

Objects, identifiers, and versioning

Objects stored in Key Vault are versioned whenever a new instance of an object is created. Each version is assigned a unique identifier and URL. When an object is first created, it's given a unique version identifier and marked as the current version of the object. Creation of a new instance with the same object name gives the new object a unique version identifier, causing it to become the current version.

Objects in Key Vault can be addressed by specifying a version or by omitting version for operations on current version of the object. For example, given a Key with the name MasterKey, performing operations without specifying a version causes the system to use the latest available version. Performing operations with the version-specific identifier causes the system to use that specific version of the object.

Vault-name and Object-name

Objects are uniquely identified within Key Vault using a URL. No two objects in the system have the same URL, regardless of geo-location. The complete URL to an object is called the Object Identifier. The URL consists of a prefix that identifies the Key Vault, object type, user provided Object Name, and an Object Version. The Object Name is case-insensitive and immutable. Identifiers that don't include the Object Version are referred to as Base Identifiers.

For more information, see Authentication, requests, and responses

An object identifier has the following general format (depending on container type):

  • For Vaults: https://{vault-name}{object-type}/{object-name}/{object-version}

  • For Managed HSM pools: https://{hsm-name}{object-type}/{object-name}/{object-version}


See Object type support for types of objects supported by each container type.


Element Description
vault-name or hsm-name The name for a vault or an Managed HSM pool in the Microsoft Azure Key Vault service.

Vault names and Managed HSM pool names are selected by the user and are globally unique.

Vault name and Managed HSM pool name must be a 3-24 character string, containing only 0-9, a-z, A-Z, and -.
object-type The type of the object, "keys", "secrets", or 'certificates'.
object-name An object-name is a user provided name for and must be unique within a Key Vault. The name must be a 1-127 character string, starting with a letter and containing only 0-9, a-z, A-Z, and -.
object-version An object-version is a system-generated, 32 character string identifier that is optionally used to address a unique version of an object.

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