Android Data Call

I am looking to develop a secure voice communication software for Android that works of over CSD data call or UMTS, with following features ## Deliverables I am looking to develop a secure voice communication software for Android that works of over CSD data call or UMTS, with following features: a) AES-256 bit voice data encryption b) possiblity to configure and compile for one of the following? i) ? Diffie-Hellman 1024/2048 Bit ii) Elliptic Curve Diffie-Helman 521 Bit new keys shall be created for every phone call. and c) Authentication using, compile time possibility to use one of following i) SHA -1 ii) ? SHA -256 iii) SHA -512 Diffie Hellmen key exchange and encryption of voice data using 256-bit AES. If you have some suggestions for improvement or simiplicity they are welcome.