Android calling App for voice, video calls and text using AES-256 Cryptography Algorithm -- 2

My team and I are looking for an experienced Freelancer to help us create an Android calling app that utilizes voice, video calls, and text messaging. This app should feature a vibrant, colorful UI, and employ standard encryption using the AES-256 Cryptography Algorithm. We would also love the app to be able to work offline, with optional VoIP calls in case of network interruptions. It is essential for the app to ensure that calls are secure, so rigorous testing must be done. We look forward to working with you to develop this project - please let us know if you have any further questions.