vault/website/source/docs/enterprise/identity/index.html.md

---
layout: "docs"
page_title: "Vault Enterprise Identity"
sidebar_current: "docs-vault-enterprise-identity"
description: |-
  Vault Enterprise has the foundations of the identity management system.
---

# Vault Enterprise Identity

In version 0.8, Vault introduced the foundations of identity management system.
The goal of identity in Vault is to associate a notion of caller identity to
the tokens used in Vault.

## Concepts

### Entities and Aliases

Each user will have multiple accounts with various identity providers. Users
can now be mapped as `Entities` and their corresponding accounts with
authentication providers can be mapped as `Aliases`. In essence, each entity is
made up of zero or more aliases.

### Entity Management

Entities in Vault **do not** automatically pull identity information from
anywhere. It needs to be explicitly managed by operators. This way, it is
flexible in terms of administratively controlling the number of entities to be
synced against Vault. In some sense, Vault will serve as a _cache_ of
identities and not as a _source_ of identities.

### Entity Policies

Vault policies can be assigned to entities which will grant _additional_
permissions to the token on top of the existing policies on the token. If the
token presented on the API request contains an identifier for the entity and if
that entity has a set of policies on it, then the token will be capable of
performing actions allowed by the policies on the entity as well.

This is a paradigm shift in terms of _when_ the policies of the token get
evaluated. Before identity, the policy names on the token were immutable (not
the contents of those policies though). But with entity policies, along with
the immutable set of policy names on the token, the evaluation of policies
applicable to the token through its identity will happen at request time. This
also adds enormous flexibility to control the behavior of already issued
tokens.

Its important to note that the policies on the entity are only a means to grant
_additional_ capabilities and not a replacement for the policies on the token.
To know the full set of capabilities of the token with an associated entity
identifier, the policies on the token should be taken into account.

### Mount Bound Aliases

Vault supports multiple authentication backends and also allows enabling the
same type of authentication backend on different mount paths. The alias name of
the user will be unique within the backend's mount. But identity store needs to
uniquely distinguish between conflicting alias names across different mounts of
these identity providers. Hence, the alias name in combination with the
authentication backend mount's accessor, serve as the unique identifier of an
alias.

### Implicit Entities

Operators can create entities for all the users of an auth mount beforehand and
assign policies to them, so that when users login, the desired capabilities to
the tokens via entities are already assigned. But if that's not done, upon a
successful user login from any of the authentication backends, Vault will
create a new entity and assign an alias against the login that was successful.

Note that the tokens created using the token authentication backend will not
have an associated identity information. Logging in using the authentication
backends is the only way to create tokens that have a valid entity identifiers.

### Identity Auditing

If the token used to make API calls have an associated entity identifier, it
will be audit logged as well. This leaves a trail of actions performed by
specific users.

### Identity Groups

In version 0.9, Vault identity has support for groups. A group can contain
multiple entities as its members. A group can also have subgroups. Policies set
on the group is granted to all members of the group. During request time, when
the token's entity ID is being evaluated for the policies that it has access
to; along with the policies on the entity itself, policies that are inherited
due to group memberships are be granted.

### Group Hierarchical Permissions

Entities can be direct members of groups, in which case they inherit the
policies of the groups they belong to. Entities can also be indirect members of
groups. For example, if a GroupA has GroupB as subgroup, then members of GroupB
are indirect members of GroupA. Hence, the members of GroupB will have access
to policies on both GroupA and GroupB.

### External vs Internal Groups

By default, the groups created in identity store are called the internal
groups. The membership management of these groups should be carried out
manually. A group can also be created as an external group. In this case, the
entity membership in the group is managed semi-automatically. External group
serves as a mapping to a group that is outside of the identity store. External
groups can have one (and only one) alias. This alias should map to a notion of
group that is outside of the identity store. For example, groups in LDAP, and
teams in GitHub. A username in LDAP, belonging to a group in LDAP, can get its
entity ID added as a member of a group in Vault automatically during *logins*
and *token renewals*. This works only if the group in Vault is an external
group and has an alias that maps to the group in LDAP. If the user is removed
from the group in LDAP, that change gets reflected in Vault only upon the
subsequent login or renewal operation.

### API

Vault identity can be managed entirely over the HTTP API. Please see [Identity
API](/api/secret/identity/index.html) for more details.