Abstract: Disclosed are various embodiments for determining authentication assurance from a combination of historical and runtime-provided inputs. An authentication request associated with an account is received. A composite measure of authentication assurance is determined from a combination of a historical measure of authentication assurance and a runtime measure of authentication assurance. A response to the authentication request is generated based at least in part on the composite measure of authentication assurance.

Abstract: Disclosed are various embodiments for determining authentication assurance using algorithmic decay. In an embodiment, an authentication request associated with an account is received. At least one historical authentication event associated with the account is determined. A measure of authentication assurance is determined based at least in part on applying an exponential time decay to at least one authentication assurance value individually corresponding to the historical authentication event(s). A response to the authentication request is generated based at least in part on the measure of authentication assurance.

Abstract: Disclosed are various embodiments for determining authentication assurance based on both user-level and account-level indicators. An authentication request associated with an account is received responsive to an input from a user via a user interface. A user-level measure of authentication assurance corresponding to the user is determined. An account-level measure of authentication assurance corresponding to the account is determined. A composite measure of authentication assurance is then determined from a combination of the user-level measure of authentication assurance and the account-level measure of authentication assurance. A response to the authentication request is generated based at least in part on comparing the composite measure of authentication assurance to a threshold.