Authentication is a prime challenge for banks today as end users’ digital identities are being compromised through increasingly sophisticated means. This chapter provides a timely review of the authentication concept and key authentication technologies, namely password tokens, biometrics, smart cards, smart tokens, and out-of-band authentication. An integrative model is proposed, which frames three key considerations in choosing an authentication solution—cyber threat types, regulatory requirements, and business considerations. Each of the implications is considered in turn. Finally, to guide future deployments of authentication solutions, the chapter concludes with pragmatic suggestions by proposing a set of evaluation criteria for choosing authentication solutions and key legal considerations.