A first set of device usage characteristics of a first user interaction with a user communication device are received. For example, a device usage characteristic may be an average key pressure, a used WiFi access point, an install date of an application, an angle of a user communication device, etc. The first set of device usage characteristics of the first user interaction are compared to a second set of device usage characteristics of a second user interaction with the user communication device that is stored in a blockchain. One or more reason codes that identifies why the first and second compared sets of device usage characteristics do not match is generated in response to the first and second compared sets of device usage characteristics not matching. The one or more reason codes are used for identifying a level of trust of a user in a communication session.