LTO API client libraries

It's recommended to use one of the LTO API client libraries if available. These libraries are configured to correctly sign requests.

Client libraries

HTTP Signature

All requests need to be signed following the HTTP Signatures specification using your ED25519 key set. Each request must have Date header. Request with a body like POST and PUT requests, must have a Content-Type and Digest header. The (request-uri) must also be part of the signature.

The KeyId must be the base58 encoded public ED25519 key. The algorithm may be either ed25519 or ed25519-sha256. If you use the the SHA-256 version, the signature string needs to be hashed. The signature must be base64 encoded as required by the http signatures specifications.


The HTTP signature string is only constructed from the HTTP headers, not the body. To make sure the body hasn't been manipulated, requests are required to have a Digest header as described in RFC 3230. The digest needs to be a SHA-256 hash.

Note that the Digest header, is a different specification than HTTP Digest Authentication.


In a process actors need to have an identity, before they can perform any action. Each identity has a signature and encryption key pair.

An identity can be give one of three authorization levels

  • A participant is only able to participate in existing processes.

  • A user is allowed to create new processes and participate in them.

  • An admin can manage all users, scenarios and processes.

    "id": "1d25b6e0-e9d8-11e9-a36f-ff0ea1118e81",
    "signkey": "5LucyTBFqSeg8qg4e33uuLY93RZqSQZjmrtsUydUNYgg",
    "encryptkey": "CLpT61PqmYNpPH5CpJQnYKLpq4kaegjPSG4vY9rGtfm3",
    "authz": "participant"

It's recommended to create key pairs using the LTO API library and only send the public keys to the service.

Multiple sign keys

You may specify additional sign keys for an identity. The identity may use any of the sign keys to sign a request. This is typically only necessary for distributed workflows.

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