2CHK is a secure app linked to a secure data communication channel. It is used for security and authentication purposes. For end users whose financial services firms subscribe to the 2CHK service, it offers a secure second communication channel over which the institution can query the user, and the user can verify and authorize activities and transactions affecting their financial accounts. The service is intended to defeat man-in-the-middle, man-in-the-browser and other financial account takeover and hijacking exploits. 2CHK also has applications in enterprise security schemas for providing strong, two-factor authentication via an out-of-band connection to the end users smart phone. Additionally, 2CHK can be used in situations when a sensitive message must be delivered, but email or SMS text do not offer an appropriate level of security for HIPPA compliance or other legal requirements.