SIP Softphone App for Android and Iphone

We have our own telephony infrastructure and we now require a SIP softphone App to connect to our platform for our team to use. I need a sip softphone application for Android and IOS, with support for TLS,SRTP,ZRTP and XMMP(encrypted). Features required. * Full support for TLS,SRTP,ZRTP and XMMP(encrypted). * Full Source Code to make mods after project completion. * Support G729, G723, Codecs * Application should work all Networks 3G/Wi-Fi/2G or GPRS. * Phone full contact book sync * Real time Balance Display * Loudspeaker * Account to Account Balance transfer * Call Duration * Call Log * Redial/Call from Call logs * Simple to use User Friendly Interface. I need only expert and very experienced in SIP Phones to integrate with our existent FreeSwitch+A2Billing and Asterisk+A2Billing servers. I'll hire best bidder with best experience and will hire on permanent basis for Technical Support as well. Full understanding of all Codecs.