Add test harness for RustCrypto rsa crate

[ueno]

No description provided.

[tomato42]

@ueno why delete?

[tomato42]

merged as 752907f, thanks!

[haraldh]

@ueno @tomato42 I somehow miss std::hint::black_box here for:

        let _ = privkey.decrypt(Pkcs1v15Encrypt, &buffer);

[tomato42]

@haraldh Sorry, I'm not a rust developer, so could you explain it like I'm 5?

[haraldh]

The compiler knows, that privkey was not modified in that function call and neither buffer.. and since you throw away the return value, in theory the compiler could just optimize away the whole line. This can be prevented by wrapping it with std::hint::black_box()

[tomato42]

@haraldh wouldn't that require the compiler to know that the decrypt() has no side-effects? I'd be surprised if that was the default for library APIs...

[haraldh]

Well, do you know, if the function has no inline=always? If the rust compiler does not do incremental compilation it might have knowledge of no side effects. Rust libs are not like C libs. Better use the black box hint every time for such cases. It does not hurt and saves you from surprises. These hints exist for other languages also.

[tomato42]

@haraldh is this sufficient?: a26abdb

[haraldh]

@haraldh is this sufficient?: a26abdb

perfect!