Techniques described herein may be used to encrypt a telephone call between users. User devices (e.g., smart phones) may be connected to encryption relay devices that operate as relays between headsets worn by the user and the user devices. As information passes from the headset toward a corresponding user device, an encryption relay device may encrypt the information before the information reaches the user device so that the user device transmits encrypted call information to the other user participating in the call. When encrypted information is received, and travels from the user device to the headset, the encryption relay device may decrypt the information before it reaches the headset. Thus, the techniques described herein provide an end-to-end encryption solution to telephone calls.