Search Results We have found 10 items matching your search query. Close Secure Voice VOIP Mobile voice app. Uses the ZRTP protocol. Changes encryption key after each call. Android only. More Details CSipSimple VOIP SIP app for Android. Secure calls with TLS transport for SIP and SRTP or ZRTP for media. More Details Phoner VOIP SIP app for Windows. Secure calls use SRTP or ZRTP. More Details PrivateWave VOIP Voice apps for mobile devices. Features security compliance with FIPS, NIST and NSA. More Details Twinkle VOIP Voice app for Linux. Features standard ZRTP and SRTP encryption protocols . More Details Kryptotel VOIP Voice app for mobile. Features texting and video. More Details Zfone Developer Tools Plugin to make VOIP apps secure using the ZRTP protocol. SDK available for developers. More Details Silent Phone Telephone Mobile VOIP software and hardware. Features messaging and file transfer. Silent Phone was sold to Office Tone in August 2018. More Details Acrobits Telephone Provider of branded VOIP/SIP software to corporations and telecom companies that operates independently or with a PBX. Software supports ZRTP and SRTP. More Details Linphone VOIP SIP app for mobile and desktop. Supports SRTP and ZRTP. Free. More Details 1 Page 1 of 1