Unwanted and fraudulent calls are a nuisance and have created a massive problem for communications service providers and subscribers alike. Importantly they have contributed a loss of trust in the public telephone network.
The Federal Communications Commission (FCC) tells us that US consumers are deluged with unwanted calls, receiving over 100,000 of them every minute, and that 47% of those calls are illegal scams. Therefore the FCC and CRTC have mandated that carriers must implement the STIR/SHAKEN framework by Sep 2020 in Canada and Jun 2021 in the USA.
STIR/SHAKEN is an implementation of the idea of marking known trusted calls, allowing service providers to digitally sign calls from known trusted sources in a way that cannot be tampered with through the network.
With STIR/SHAKEN deployed, the impenetrable wall surrounding the public telephone network is re-asserted for known, trusted callers, and a network-wide subset of trust can be rebuilt around call signing.