not if it's backdoored. end-to-end doesn't mean it's actually secure. there's 0% chance that there isn't some apple-owned backdoor, key escrow system, or other scheme. "end-to-end" means nobody has the keys and nobody can read the data except for the end user. And of course apple (via super-duper security backup key, non acknowledged). And the 5 eye's TLAs. And so on.

I wouldn't trust any of these guys for a millisecond.