Authentication procedures with randomization of private input interface

An apparatus, comprising:

• one or more processing elements configured to:
• receive configuration information for user input of a passcode to another device, wherein the configuration information specifies a pseudo-random relationship of input values to input actions recognized by the other device;
• and
• display, based on the configuration information, a private interface that is visible to a user of the apparatus and not to other users, wherein the private interface indicates the relationship of the input values to the input actions.

A non-transitory computer-readable medium having instructions stored thereon that are executable by a computing device to perform operations comprising:

• determining to perform an authentication procedure for a user;
• pseudo-randomly determining relationships between input values for the authentication procedure and input actions performed by a user to signal respective different inputs to the computing device;
• wirelessly transmitting configuration information that specifies the determined relationships to a mobile device associated with the user;
• and
• determining whether user input matches an expected passcode, wherein the user input is received based on display, by the mobile device, of a private interface that is visible to a user of the computing device and not to other users, wherein the private interface indicates the relationship of the input values to the input actions.