Quote from: ivakar on October 16, 2019, 08:53:23 AM

strange, but yobit, for example, is not working with any authenticator. but google

Have you tried using a different authenticator? Many websites, including some that I use with andOTP, say the user needs to use Google Authenticator, but work just fine with other authenticators.

Quote from: ivakar on October 16, 2019, 08:53:23 AM

i thought that every Authenticator should have own algo inside it

The algorithm is the same. The website provides a shared secret key, which you scan in the form of a QR code when you set it up for the first time. The authenticator uses that key, along with the current time, to generate a code. The website does the same thing to see if the code matches.

Quote from: ivakar on October 16, 2019, 08:53:23 AM

but it is possible to copy the code, modify it, then create fishing site and distribute some bad app, right?

So don't download from unofficial sources. Problem solved.

Quote from: ivakar on October 16, 2019, 08:53:23 AM

I agree that we do not know what's inside google auth, but it is used very wide,so if there was a security breach I think it would be known already.

This is a flawed argument I'm afraid. Windows is far more widely used than Google Authenticator. So is iOS. So is Android. So is Chrome, and Firefox, and Edge, etc, etc. All of these have been subjected to very bad security breaches and exploits. Widely used does not automatically mean safe.