---
layout: "docs"
page_title: "Secret Backend: Transit"
sidebar_current: "docs-secrets-transit"
description: |-
  The transit secret backend for Vault encrypts/decrypts data in-transit. It doesn't store any secrets.
---

# Transit Secret Backend

Name: `transit`

The transit secret backend is used to encrypt/data in-transit. Vault doesn't
store the data sent to the backend. It can also be viewed as "encryption as
a service."

The primary use case for the transit backend is to encrypt data from
applications while still storing that encrypted data in some primary data
store. This relieves the burden of proper encryption/decryption from
application developers and pushes the burden onto the operators of Vault.
Operators of Vault generally include the security team at an organization,
which means they can ensure that data is encrypted/decrypted properly.

Additionally, since encrypt/decrypt operations must enter the audit log,
any decryption event is recorded.

This page will show a quick start for this backend. For detailed documentation
on every path, use `vault help` after mounting the backend.

## Quick Start

The first step to using the transit backend is to mount it. Unlike the `generic`
backend, the `transit` backend is not mounted by default.

```
$ vault mount transit
Successfully mounted 'transit' at 'transit'!
```

The next step is to create a named encryption key. A named key is used so that
many different applications can use the transit backend with independent keys.
This is done by doing a write against the backend:

```
$ vault write transit/keys/foo test=1
Success! Data written to: transit/keys/foo
```

This will create the "foo" named key in the transit backend. We can inspect
the settings of the "foo" key by reading it:

```
$ vault read transit/keys/foo
Key        	Value
name       	foo
cipher_mode	aes-gcm
key        	PhKFTALCmhAhVQfMBAH4+UwJ6J2gybapUH9BsrtIgR8=
````

Here we can see that the randomly generated encryption key being used, as
well as the AES-GCM cipher mode. We don't need to know any of this to use
the key however.

Now, if we wanted to encrypt a piece of plain text, we use the encrypt
endpoint using our named key:

```
$ echo "the quick brown fox" | base64 | vault write transit/encrypt/foo plaintext=-
Key       	Value
ciphertext	vault:v0:czEwyKqGZY/limnuzDCUUe5AK0tbBObWqeZgFqxCuIqq7A84SeiOq3sKD0Y/KUvv
```

The encryption endpoint expects the plaintext to be provided as a base64 encoded
strings, so we must first convert it. Vault does not store the plaintext or the
ciphertext, but only handles it _in transit_ for processing. The application
is free to store the ciphertext in a database or file at rest.

To decrypt, we simply use the decrypt endpoint using the same named key:

```
$ vault write transit/decrypt/foo ciphertext=vault:v0:czEwyKqGZY/limnuzDCUUe5AK0tbBObWqeZgFqxCuIqq7A84SeiOq3sKD0Y/KUvv
Key      	Value
plaintext	dGhlIHF1aWNrIGJyb3duIGZveAo=

$ echo "dGhlIHF1aWNrIGJyb3duIGZveAo=" | base64 -D
the quick brown fox
```

Using ACLs, it is possible to restrict using the transit backend such
that trusted operators can manage the named keys, and applications can
only encrypt or decrypt using the named keys they need access to.

## API

### /transit/keys/
#### POST

<dl class="api">
  <dt>Description</dt>
  <dd>
    Creates a new named encryption key. This is a root protected endpoint.
  </dd>

  <dt>Method</dt>
  <dd>POST</dd>

  <dt>URL</dt>
  <dd>`/transit/keys/<name>`</dd>

  <dt>Parameters</dt>
  <dd>
    None
  </dd>

  <dt>Returns</dt>
  <dd>

    ```javascript
    {
      "data": {
          "name":        "foo",
          "cipher_mode": "aes-gcm",
          "key":         "PhKFTALCmhAhVQfMBAH4+UwJ6J2gybapUH9BsrtIgR8="
      }
    }
    ```

  </dd>
</dl>

#### GET

<dl class="api">
  <dt>Description</dt>
  <dd>
    Returns information about a named encryption key.
    This is a root protected endpoint.
  </dd>

  <dt>Method</dt>
  <dd>GET</dd>

  <dt>URL</dt>
  <dd>`/transit/keys/<name>`</dd>

  <dt>Parameters</dt>
  <dd>
    None
  </dd>

  <dt>Returns</dt>
  <dd>

    ```javascript
    {
      "data": {
          "name":        "foo",
          "cipher_mode": "aes-gcm",
          "key":         "PhKFTALCmhAhVQfMBAH4+UwJ6J2gybapUH9BsrtIgR8="
      }
    }
    ```

  </dd>
</dl>

#### DELETE

<dl class="api">
  <dt>Description</dt>
  <dd>
    Deletes a named encryption key. This is a root protected endpoint.
    All data encrypted with the named key will no longer be decryptable.
  </dd>

  <dt>Method</dt>
  <dd>DELETE</dd>

  <dt>URL</dt>
  <dd>`/transit/keys/<name>`</dd>

  <dt>Parameters</dt>
  <dd>
    None
  </dd>

  <dt>Returns</dt>
  <dd>
    A `204` response code.
  </dd>
</dl>

### /transit/encrypt/
#### POST

<dl class="api">
  <dt>Description</dt>
  <dd>
    Encrypts the provided plaintext using the named key.
  </dd>

  <dt>Method</dt>
  <dd>POST</dd>

  <dt>URL</dt>
  <dd>`/transit/encrypt/<name>`</dd>

  <dt>Parameters</dt>
  <dd>
    <ul>
      <li>
        <span class="param">plaintext</span>
        <span class="param-flags">required</span>
        The plaintext to encrypt, provided as base64 encoded.
      </li>
    </ul>
  </dd>

  <dt>Returns</dt>
  <dd>

    ```javascript
    {
        "data": {
            "ciphertext": "vault:v0:abcdefgh"
        }
    }
    ```

  </dd>
</dl>

### /transit/decrypt/
#### POST

<dl class="api">
  <dt>Description</dt>
  <dd>
    Decrypts the provided ciphertext using the named key.
  </dd>

  <dt>Method</dt>
  <dd>POST</dd>

  <dt>URL</dt>
  <dd>`/transit/decrypt/<name>`</dd>

  <dt>Parameters</dt>
  <dd>
    <ul>
      <li>
        <span class="param">ciphertext</span>
        <span class="param-flags">required</span>
        The ciphertext to decrypt, provided as returned by encrypt.
      </li>
    </ul>
  </dd>

  <dt>Returns</dt>
  <dd>

    ```javascript
    {
        "data": {
            "plaintext": "dGhlIHF1aWNrIGJyb3duIGZveAo="
        }
    }
    ```

  </dd>
</dl>