1. A computer-implemented method, comprising: in response to an attempt by a user to perform a transaction using a computing device, accessing a communication device connected to the computing device; detecting, through use of the communication device connected to the computing device, a presence of a current set of nearby devices, wherein each of the current set of nearby devices is located geographically nearby the computing device when the transaction is attempted; applying, to the current set of nearby devices located geographically nearby the computing device when the transaction is attempted, a dynamic mapping of devices to trust levels; wherein, in the dynamic mapping, each potential set of nearby devices maps to a trust level of two or more trust levels, wherein the dynamic mapping is based on a record of past transactions, and wherein the record of past transactions indicates which devices were geographically nearby during the past transactions; determining an assigned trust level for the transaction based on the applying, to the current set of nearby devices located geographically nearby the computing device when the transaction is attempted, the dynamic mapping of devices to trust levels; identifying a second computing device as being part of the current set of nearby devices located geographically nearby the computing device when the transaction is attempted; and modifying the dynamic mapping of devices to trust levels based on the current set of nearby devices located geographically nearby the computing device when the transaction is attempted; wherein modifying the dynamic mapping results in an increased trust level when the second computing device is geographically nearby the computing device for the future transactions, responsive to the second computing device being geographically nearby the first computing device when the transaction is attempted; and wherein the modified dynamic mapping is used for future transactions.