<p>As Google strongly restricts the use of SMS permissions for applications in the Play-Store, S2MSP provides an API for third party applications to send and receive SMS to specific phone numbers via a secure SMS proxy.</p><p>S2MSP acts like a local firewall for SMS communication.</p><p>Each application that wants to send/receive SMS to a phone number can register itself on S2MSP. S2MSP asks the user for permission, whether the requesting application is allowed to send/receive SMS from and to the requested phone numbers or not.</p><p>All SMS exchanged with third party applications are strongly encrypted.</p><p>S2SMP itself requires SMS permissions (<code>SEND_SMS</code> and <code>RECEIVE_SMS</code>) from the Android system and will request these permissions upon startup. S2MSP does not need any other permissions. This ensures the integrity and security of S2MSP.</p><p>The API to integrate a third party application with S2MSP is available in Maven-Central.</p>