What is a "token" in the context of Vault?

In the context of HashiCorp Vault, a "token" serves as a credential that is used to authenticate and authorize requests made to the Vault API. This means that when a user or application wants to interact with Vault, they present a token that signifies their identity and associated permissions. Tokens are issued by Vault and can be configured with policies that determine the scope of actions a user or service can perform, such as reading or writing secrets.

The functionality of tokens is crucial to maintaining security and managing access control within Vault, as they provide a way to validate the identity of the requester and enforce the appropriate level of access. By using tokens, Vault ensures that sensitive operations are performed only by authorized entities, thereby safeguarding the secrets stored within the system.

Other options, while relevant in potential contexts, do not accurately represent the specific role of tokens in Vault. For instance, a unique identifier for services refers more to service registration and discovery, a physical access key pertains to tangible security measures like doors, and a method for data encryption relates to protecting data in transit or at rest—not to the mechanism of authentication and authorization provided by tokens.