I am looking for VoIP software that is compatible with smartphones.

Ideally I would like to have the following features:

  1. Ability to set a different phone number from my regular phone number that other people can use to contact me.

  2. Ability to make and receive calls and texts inside the US.

  3. Strong encryption to protect phone calls from more sophisticated illegal/unlawful eavesdroppers such as hackers. Not concerned with NSA or other authorities.

Any suggestions?

  • 1
    please clarify if you want just any voip-service or a sip-service, sip-server or sip-client! -- "VOIP software" ... "smartphones" sounds like a client-recommendation for any voip-service; "different phone number" sounds like you are asking for a sip-service/-gateway...! Oct 1, 2016 at 7:58

1 Answer 1


Signal from open whisper systems would be a good bet as it is open source and is recommended by the EFF and many security experts. It meets most of your needs as it is end to end encrypted, supports voice calls and text messaging.

One thing I am not sure is practical is how would you use a different phone number than the one you have? Signal needs a phone number to send a text message with a verification code.

You could sign up for a google voice phone number (which is a virtual number) and then use that to activate Signal. But this phone number would need to be the one that other Signal users have so they can message you.

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