Actually this is reality of cryptography. Is AES secure? Well lot of people tried to break it and failed. Which does not answer the question because we don't have any mathematical tools to say yes this cryptography algorithm is formally verified to be secure and unbreakable. It can turn out that tomorrow we will find a flaw in AES which will make it leak key after capturing few blocks.
Only thing which we know is unbreakable is OTP and that's because it is easy to prove it.
Only thing which we know is unbreakable is OTP and that's because it is easy to prove it.