The 3-D Secure protocols used to authenticate cardholders in online transactions has grown steadily since the introduction of the 2.0 version in 2019. Growth was spurred by consumer protection regulations in Europe and elsewhere as well as the steady increase in the number of online transactions initiated by smartphones capable of authenticating their users with fingerprint or facial biometrics. American Express, which ranks second largest among credit card issuers in the US, has become the first card issuer in the world to supplement 3-D Secure protocols with facial and fingerprint biometr...