In this paper we propose a new authorization and authentication framework for the IoT that combines the security model of OAuth 1.0a with the lightweight building blocks of ACE. By designing self-securing tokens the security of the framework no longer depends on the security of the network stack. We use basic PKI functionalities to bootstrap a chain-of-trust between the devices which simplifies future token exchanges. Finally, we propose an alternate key establishment scheme for use cases where devices cannot directly communicate. We test our proposal by implementing the critical aspects on a STM32L4 microcontroller. The results indicate that our framework guarantees a strong level of security for IoT devices with basic asymmetric cryptography capabilities.