Circles - Encrypted E2E VOIP + app for iPhone and iPad

Circles is a FREE App and cares about your Privacy !
This App provides best in class end-to-end security and encryption on Voice and Video Calls, and for your Messages, Classifieds, Events and Location points.

Claiming security compliance for Voice and Video VOIP with NIST SP800-56 rev3 C(2e,2s) and HKDF (RFC5869) standards and using AES128, HMAC256, ECDH128, ECDSA256.

This App allows you to add contacts through the sharing of a so called public key over the internet and bluetooth.

This App allows you to cryptographically verify (out of band) that members are granted access to the same Circles than you. In addition, each Circle owner can distribute cryptographic Vouchers to their Members.

Circles properties:
When creating a Circle, you can select whether you are the only one allowed to add members to this Circle or if any other Circle member can add members to this Circle.
In addition, you can select whether you are the only one allowed to send message, image and classifieds to the Circles, or if every member of the Circle is allowed to do so.

Badging functionality:
Each Circle can be used to allow people entering events, accessing services with voucher, attest of privileges of being in a Circle

Voucher functionality:
Circles owners can distribute cryptographic vouchers.

Cloud:
Circles is automatically synchronised on all your devices running under the same icloud account using iCloud keychain and iCloud drive.
You can start a discussion on your iPhone, then continue it on your iPad, seamlessly.
Thanks to End-to-End security, all messages, images, classifieds and GPS points can be securely stored outside of your devices, in Servers.
This greatly minimise the storage consumption on your device while providing easy access to any of your device.