The next iteration in that protection is iMessage Contact Key Verification. With this feature, not only are messages end-to-end encrypted, but users can also choose to further confirm their messaging with their intended recipients.
Secure messaging app Signal does something similar already. Users of that platform can generate unique codes to compare with each other, just to make sure an account hasn’t been compromised somehow.
When iMessage Contact Key Verification comes available, this same level of protection will be incorporated into the iPhone’s stock messaging app.
Read more at MacObserver.com