TOTP secrets engine

The TOTP secrets engine generates time-based credentials according to the TOTP standard. The secrets engine can also be used to generate a new key and validate passwords generated by that key.

The TOTP secrets engine can act as both a generator (like Google Authenticator) and a provider (like the Google.com sign in service).

As a generator

The TOTP secrets engine can act as a TOTP code generator. In this mode, it can replace traditional TOTP generators like Google Authenticator. It provides an added layer of security since the ability to generate codes is guarded by policies and the entire process is audited.

Setup

Most secrets engines must be configured in advance before they can perform their functions. These steps are usually completed by an operator or configuration management tool.

Enable the TOTP secrets engine:
```
$ vault secrets enable totp
Success! Enabled the totp secrets engine at: totp/
```
By default, the secrets engine will mount at the name of the engine. To enable the secrets engine at a different path, use the -path argument.
Configure a named key. The name of this key will be a human identifier as to its purpose.
```
$ vault write totp/keys/my-key \
    url="otpauth://totp/Vault:test@test.com?secret=Y64VEVMBTSXCYIWRSHRNDZW62MPGVU2G&issuer=Vault"
Success! Data written to: totp/keys/my-key
```
The url corresponds to the secret key or value from the barcode provided by the third-party service.

Usage

After the secrets engine is configured and a user/machine has a Vault token with the proper permission, it can generate credentials.

Generate a new time-based OTP by reading from the /code endpoint with the name of the key:
```
$ vault read totp/code/my-key
Key     Value
---     -----
code    260610
```
Using ACLs, it is possible to restrict using the TOTP secrets engine such that trusted operators can manage the key definitions, and both users and applications are restricted in the credentials they are allowed to read.

As a provider

The TOTP secrets engine can also act as a TOTP provider. In this mode, it can be used to generate new keys and validate passwords generated using those keys.

Setup

Most secrets engines must be configured in advance before they can perform their functions. These steps are usually completed by an operator or configuration management tool.

Enable the TOTP secrets engine:
```
$ vault secrets enable totp
Success! Enabled the totp secrets engine at: totp/
```
By default, the secrets engine will mount at the name of the engine. To enable the secrets engine at a different path, use the -path argument.

Create a named key, using the generate option. This tells Vault to be the provider:

$ vault write totp/keys/my-user \
    generate=true \
    issuer=Vault \
    account_name=user@test.com

Key        Value
---        -----
barcode    iVBORw0KGgoAAAANSUhEUgAAAMgAAADIEAAAAADYoy0BA...
url        otpauth://totp/Vault:user@test.com?algorithm=SHA1&digits=6&issuer=Vault&period=30&secret=V7MBSK324I7KF6KVW34NDFH2GYHIF6JY

The response includes a base64-encoded barcode and OTP url. Both are equivalent. Give these to the user who is authenticating with TOTP.

Usage

As a user, validate a TOTP code generated by a third-party app:

$ vault write totp/code/my-user code=886531
Key      Value
---      -----
valid    true

API

The TOTP secrets engine has a full HTTP API. Please see the TOTP secrets engine API for more details.