Systems and methods for authenticating a request between a client computer and a transaction server are provided. An application request, comprising an identity of a user originating the request, is received at an application server from the client. The application server constructs a signing key based on (i) the identity of the user making the request, (ii) a time based salt value, (iii) a secret shared between the application and transaction servers and, optionally, (iv) an identifier of the distributor or developer of the application. The signing key is embedded in an unbranded version of the application thereby branding the application. The branded application can sign a request with the signing key and submit the signed request to the transaction server with the identity of the user and the identifier of the distributor or developer of the application.