What does STIR/SHAKEN stand for?

Secure Telephone Identity Revisited and Signature-based Handling of Asserted Information Using toKENs

STIR/SHAKEN, is a suite of protocols and procedures intended to combat caller ID spoofing on public telephone networks. STIR and SHAKEN uses digital certificates, based on common public key cryptography techniques, to ensure the calling number of a telephone call is secure. In simple terms, each telephone service provider obtains their digital certificate from a certificate authority who is trusted by other telephone service providers.