Signature-based Handling of Asserted information using toKENs (SHAKEN) is an industry framework for managing the deployment of Secure Telephone Identity (STI) technologies with the purpose of providing end-to-end cryptographic authentication and verification of the Telephone Identity and other information in an Internet Protocol (IP)-based service provider voice network. This specification defines the framework for telephone service providers to create signatures in Session Initiation Protocol (SIP) and validate initiators of signatures. It defines the various classes of signers and how the verification of a signature can be used towards the mitigation and identification of illegitimate use of national telecommunications infrastructure.