Access to some Node API calls is restricted, and the client should authenticate to use them. To authenticate, the client should provide a corresponding authentication token or sign the request body with the home node’s private signing key.

Read also the overview of the authentication architecture in Moera.

Types of tokens

There are several types of tokens that may be used for authentication.

Root secret

Root secret is set in the server configuration and is used to authenticate as a topmost administrator (root admin) of the server.

Admin token

Admin token is used to authenticate as administrator on the home node. The client should get login and password from the user and then call Node API to generate the token.


Carte (from carte-de-visite) is a cryptographic token that allows the client to authenticate on any node besides the home node.

Nodes in Moera use public key cryptography to authenticate one another. Since the client does not have access to the private signing key (giving such access would weaken the security), it would need to ask the home node to sign every request that needs authentication or to perform authentication on every node individually. Carte is a compromise between security and performance, it gives acceptable user experience, while minimizing damage if some cartes are leaked.

After authentication on the home node, the client requests a set of cartes. Each carte is a BASE64-encoded array of bytes that is a concatenation of CarteFingerprint and its signature.

carte = fingerprint + signature

The fingerprint contains the name of the home node, the IP address of the client, optional name of the target node, beginning and end timestamps of the carte’s life and a random salt. Binding to time, IP address and target node minimizes the ability of an attacker to use a carte that was intercepted somehow. For the same reason, it is recommended to use cartes with a short lifetime (several minutes). If the client needs to work longer, it can request several cartes in a single request that correspond to successive periods of time. When one carte expires, the client throws it off and uses the next one in the sequence.


If the client wants to post a content (comment, reaction etc.) to a node, carte authentication is not enough because the content needs its own signature. To provide better user experience, the client may use carte to post a temporary content without a signature and then ask the home node to post its signed version. If during a short period of time the signed content does not arrive, the node erases the temporary version.

Passing the token

The recommended way to pass the token with a request is to set Authorization HTTP header with Bearer authentication scheme. The token should be prefixed with its type. For example:

Authorization: bearer secret:<root secret>
Authorization: bearer <admin token>
Authorization: bearer token:<admin token>
Authorization: bearer carte:<carte>

In situations, when the client cannot change request headers, it can use auth= parameter in the URL of the request to pass the token. This method is not recommended because request URLs usually appear in server and proxy logs.

For example:<request URL>?auth=secret:<root secret><request URL>?auth=<admin token><request URL>?auth=token:<admin token><request URL>?auth=carte:<carte>

To authenticate the event stream the client should pass the token in the token: header of CONNECTED STOMP frame. For example:

token:secret:<root secret>
token:<admin token>
token:token:<admin token>