RSA Authentication

[rctl]

Enhances security by enabling RSA authentication for numbers, old numbers that previously used authentication keys will be automatically upgraded to RSA authentication and the authentication key will be disabled. This makes it harder to gain control of a number as the effective key length is drastically increased and the server-side stored number files no longer contain any sensitive data at all. The private key is only stored on the device that first claimed the number, when that devices storage is cleared there is no way to ever re-use the numbers without wiping the server storage to forget the directory of used numbers. This also opens the ability for the server to request clients to sign additional data associated with a number.

Planned for next update: Have devices store a numbers public key on first contact with that number and reject any other attempts to initialize calls with that number in the future if the public key has been altered. Also allow for two devices to exchange voice encryption keys using these certificates and do visual comparison of the certificates fingerprints.

This version also enhances user experience by adding vibration on incoming calls and dial tones on outgoing calls.