Single step transaction authentication using proximity and biometric input

A system comprising:

• a computing device and a memory including instructions that, when executed by the computing device, cause the system to perform operations including:
• automatically acquiring, by a portable user device, a facial image of a user and computing a hash of the facial image using a one-way hash function;
• comparing, by the portable user device, the hash of the facial image of the user and a biometric profile stored in the portable user device, the biometric profile comprising biometric information transformed by the one-way hash function and a use of the biometric profile for user authentication associated with it a spending limit on a purchase amount of a transaction;
• responsive to the comparing, determining that the hash of the facial image of the user matches the biometric profile;
• responsive to determining that the hash of the facial image of the user matches the biometric profile, detecting that the portable user device is within a proximity zone of a reader device, establishing a wireless communication channel between the portable user device and the reader device, receiving a profile history including an identification of a first trusted system that administered an acquisition and storage of the biometric profile and a transaction history including one or more transactions completed using the portable user device from the portable user device via the wireless communication channel, determining that the portable user device is valid based on authenticating the profile history and the transaction history, and determining that the biometric profile associated with a valid user for the portable user device;
• and
• responsive to determining that the portable user device is valid, that the biometric profile is associated with the valid user for the portable user device, and that the purchase amount of the transaction is within the spending limit associated with the use of the biometric profile for user authentication, transmitting transaction information for the transaction from the portable user device to the reader device via the wireless communication channel and initiating, at the reader device, the transaction, the reader device requesting a validation of the transaction information from a second trusted system and performing the transaction using the transaction information responsive to receiving the validation of the transaction information from the second trusted system.