Mobile phone call encryption

Encrypting (GSM) mobile phone calls over VPN with an Asterisk PBX

Paul Wouters and Leigh Honeywell

Playlists: '23c3' videos starting here / audio / related events

To encrypt all your mobile phones to protect it from overzealous eavesdroppers, you are currently limited to using special hardware such as the Cryptophone. The disadvantage of cryptophone is that it only works with other cryptophones. To work around this, we turn mobile phones from "voice" phones into VOIP phones. Using the SIP protocol for VOIP and IPsec/L2TP or Openvpn as our VPN, Leigh Honeywell and Paul Wouters connect their mobile phones fully encrypted to an Asterisk PBX server.