Just because the OP didn't use unsafe {} anywhere in their code doesn't mean it's not used in any dependencies. Just glancing at some of the deps I can already see there is a lot of unsafe usage deep down that are "wrapped" in safe interfaces. Rust is not some kind of silver bullet for safety. It just makes it more explicit.

Also, I'm less concerned about the memory safety than the _complete reimplementation of SSH_ from scratch. So give me OpenSSH any day for things that are actually important.