System and Method for Authenticating Payment Transactions

A method for authorizing a payment transaction initiated on a mobile client device connected to a cellular communication network, the method comprising:

• at a system having one or more processors and memory storing one or more programs for execution by the one or more processors to perform the method:
• receiving a request to authorize a payment transaction initiated on a portable client device connected to a cellular communications network, the request comprising first client device data including an IP address and a unique identifier both associated with the client device;
• querying an authentication system using a subset of the first client device data;
• receiving a response from the authentication system, wherein the response includes second client device data distinct from the subset of the first client device data;
• and
• at least partially authorizing the payment transaction when at least some of the second client device data received from the authentication system matches at least some of the second client device data received from the client device.

An authentication system, comprising:

• one or more processors;
• memory;
• and
• one or more programs stored in the memory, the one or more programs comprising instructions for:
• receiving from a mobile client device connected to a cellular communications network a request to authorize a payment transaction initiated on the client device, where the request comprises an IP address associated with a client device and a cellular phone number associated with the client device;
• querying a carrier system associated with the cellular communications network using the cellular phone number associated with the client device;
• receiving a response from the carrier system, wherein the response includes an IP address associated with the client device;
• and
• at least partially authorizing the payment transaction when the IP address received from the carrier system matches the IP address received from the client device.

A non-transitory computer readable storage medium storing one or more programs configured for execution by one or more processors of an authentication system, the one or more programs comprising instructions for:

• receiving from a mobile client device connected to a cellular communications network a request to authorize a payment transaction initiated on the client device, where the request comprises an IP address associated with a client device and a cellular phone number associated with the client device;
• querying a carrier system associated with the cellular communications network using the cellular phone number associated with the client device;
• receiving a response from the carrier system, wherein the response includes an IP address associated with the client device;
• and
• at least partially authorizing the payment transaction when the IP address received from the carrier system matches the IP address received from the client device.