Date of last update: September 14, 2022

Authenticate and authorize JSON-RPC

Authentication identifies a user, and authorization verifies user access to requested JSON-RPC methods. Hyperledger Besu verifies users using JSON Web Tokens (JWT). JWT is also used in multi-tenancy to verify tenant data access.

Besu supports two mutually exclusive authentication methods:

Username and password
JWT public key.

Besu creates JWT internally with username and password authentication, and externally with JWT public key authentication.

Note

Using JSON-RPC authentication and authorization with MetaMask is not supported.

Important

To prevent interception of authentication credentials and authenticated tokens, make authenticated requests over HTTPS. We recommend running production deployments behind a network layer that provides SSL termination. Besu does not provide a HTTPS connection natively.

Username and password authentication

Enable authentication from the command line. Supply the credentials file and send a request to the /login endpoint using the username and password. The /login endpoint creates a JWT for making permitted JSON-RPC requests.

Using public key authentication disables the /login endpoint.

1. Create the credentials file

The toml credentials file defines user details and the JSON-RPC methods they can access.

Sample auth.toml credentials file

[Users.username1]
password = "$2a$10$l3GA7K8g6rJ/Yv.YFSygCuI9byngpEzxgWS9qEg5emYDZomQW7fGC"
permissions=["net:*","eth:blockNumber"]
privacyPublicKey="U7ANiOOd5L9Z/dMxRFjdbhA1Qragw6fLuYgmgCvLoX4="

[Users.username2]
password = "$2b$10$6sHt1J0MVUGIoNKvJiK33uaZzUwNmMmJlaVLkIwinkPiS1UBnAnF2"
permissions=["net:version","admin:*"]
privacyPublicKey="quhb1pQPGN1w8ZSZSyiIfncEAlVY/M/rauSyQ5wVMRE="

Each user requiring JSON-RPC access the configuration file lists the:

Username. Users. is mandatory and followed by the username. That is, replace <username> in [Users.<username>] with the username.
Hash of the user password. Use the password hash subcommand to generate the hash.
JSON-RPC permissions.
Optional. The tenant’s Tessera public key using privacyPublicKey. Only used for multi-tenancy.

Password hash subcommand

CommandHash output

besu password hash --password=MyPassword

$2a$10$L3Xb5G/AJOsEK5SuOn9uzOhpCCfuVWTajc5hwWerY6N5xBM/xlrMK

2. Enable authentication

To require authentication for the JSON-RPC API, use the --rpc-http-authentication-enabled or --rpc-ws-authentication-enabled options.

To specify the credentials file, use the --rpc-http-authentication-credentials-file and --rpc-ws-authentication-credentials-file options.

3. Generate an authentication token

To generate an authentication token, make a request to the /login endpoint with your username and password. Specify the HTTP port or the WS port to generate a token to authenticate over HTTP or WS respectively. HTTP and WS requires a different token.

Example

Generate a token for HTTPExample for HTTPGenerate a token for WSExample for WSJSON result

curl -X POST --data '{"username":"username1","password":"MyPassword"}' <JSON-RPC-http-hostname:http-port>/login

curl -X POST --data '{"username":"username1","password":"MyPassword"}' http://localhost:8545/login

curl -X POST --data '{"username":"username1","password":"MyPassword"}' <JSON-RPC-ws-hostname:ws-port>/login

curl -X POST --data '{"username":"username1","password":"MyPassword"}' http://localhost:8546/login

{"token":"eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJwZXJtaXNzaW9ucyI6WyIqOioiXSwidXNlcm5hbWUiOiJ1c2VyMiIsImlhdCI6MTU1MDQ2MDYwNCwiZXhwIjoxNTUwNDYwOTA0fQ.l2Ycqzl_AyvReXBeUSayOlOMS_E8-DCuz3q0Db0DKD7mqyl6q-giWoEtfdWzUEvZbRRi2_ecKO3N6JkXq7zMKQAJbVAEzobfbaaXWcQEpHOjtnK4_Yz-UPyKiXtu7HGdcdl5Tfx3dKoksbqkBl3U3vFWxzmFnuu3dAISfVJYUNA"}

Authentication tokens expire five minutes after generation. If you require access after the token expires, you need to generate a new token.

JWT public key authentication

Enable authentication from the command line and supply the external JWT provider’s public key.

Important

JWT public authentication disables the Besu /login endpoint, meaning username and password authentication will not work.

1. Generate a private and public key pair

The private and accompanying public key files must be in .pem format.

The key algorithm can be:

RSA with private key length of at least 2048 bits using algorithm RS256, RS384 or RS512.
ECDSA private key, using ES256 (secp256r1 or secp256k1), ES384 or ES512.

Besu default is RS256.

Example of key generation using OpenSSL

RS256 RSA KeysES256 secp256r1 ECDSA Keys

Generate the private key:

openssl genrsa -out privateRSAKey.pem 2048

Generate the public key:

openssl rsa -pubout -in privateRSAKey.pem -pubout -out publicRSAKey.pem

Generate the private key:

openssl ecparam -name secp256r1 -genkey -out privateECDSAKey.pem

Generate the public key:

openssl ec -in privateECDSAKey.pem -pubout -out publicECDSAKey.pem

Private key security

The private key must be kept secret. Never share private keys publicly or on a Web site, even if advertised as secure.

Always keep your private keys safe – ideally using harware or vault – and define a strong security policy and best practices.

Compromised keys can provide attackers access to you nodes RPC-API.

2. Create the JWT

Create the JWT using a trusted authentication provider¹ or library in your own code.

See Java code sample to generate JWT using Vertx for an example implementation.

Important

The JWT must use one of the RS256, RS384, RS512, ES256, ES384, or ES512 algorithms.

Each payload for the JWT must contain:

JSON-RPC permissions
exp (Expiration Time) claim
Optionally, the tenant’s Tessera public key using privacyPublicKey. Only used for multi-tenancy.

JWT generation example

Example JSON PayloadExample JWT result

{
  "permissions": ["*:*"],
  "privacyPublicKey": "2UKH3VJThkOoKskrLFpwoxCnnRARyobV1bEdgseFHTs=",
  "exp": 1600899999002
}

3. Enable authentication

To require authentication for the JSON-RPC API, use the --rpc-http-authentication-enabled or --rpc-ws-authentication-enabled options.

To specify the JWT provider’s public key file to use with the externally created JWT, use the --rpc-http-authentication-jwt-public-key-file or --rpc-ws-authentication-jwt-public-key-file options.

JSON-RPC permissions

Each user has a list of permissions strings defining the methods they can access. To give access to:

All API methods, specify ["*:*"].
All API methods in an API group, specify ["<api_group>:*"]. For example, ["eth:*"].
Specific API methods, specify ["<api_group>:<method_name>"]. For example, ["admin:peers"].

With authentication enabled, to explicitly specify a user cannot access any methods, include the user with an empty permissions list ([]). Users with an empty permissions list and users not included in the credentials file cannot access any JSON-RPC methods.

Use an authentication token to make requests

Specify the authentication token as a Bearer token in the JSON-RPC request header.

Postman

In the Authorization tab in the TYPE drop-down list, select Bearer Token and specify the token (generated either externally or by the login request).

cURL

Specify the Bearer in the header.

Example

cURL Request with authentication placeholderscURL Request with authentication

curl -X POST -H 'Authorization: Bearer <JWT_TOKEN>' -d '{"jsonrpc":"2.0","method":"<API_METHOD>","params":[],"id":1}' <JSON-RPC-http-hostname:port>

curl -X POST -H 'Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJwZXJtaXNzaW9ucyI6WyIqOioiXSwidXNlcm5hbWUiOiJ1c2VyMiIsImlhdCI6MTU1MDQ2MTQxNiwiZXhwIjoxNTUwNDYxNzE2fQ.WQ1mqpqzRLHaoL8gOSEZPvnRs_qf6j__7A3Sg8vf9RKvWdNTww_vRJF1gjcVy-FFh96AchVnQyXVx0aNUz9O0txt8VN3jqABVWbGMfSk2T_CFdSw5aDjuriCsves9BQpP70Vhj-tseaudg-XU5hCokX0tChbAqd9fB2138zYm5M' -d '{"jsonrpc":"2.0","method":"net_listening","params":[],"id":1}' http://localhost:8545

for example Auth0 or Keycloak ↩