Audio encryption using FROG cipher in CBC mode + Schnorr signature + ECDH key exchange + Captcha & OTP security
Credits:
https://github.com/DimonK95/schnorr-signature
https://www.schneier.com/books/applied-cryptography-source/
https://github.com/abdamah/simpleCaptchaApp
https://neilmadden.blog/2016/05/20/ephemeral-elliptic-curve-diffie-hellman-key-agreement-in-java/