Feature Request: implementation of crypto

Hi Dart team,

Is there any plan for packages like [crypto](https://golang.org/src/crypto/) and [encoding](https://golang.org/src/encoding/) being implemented as part of the standard libs? As Dart will be running from "Server" side, so I guess packages like that will be very useful.

I'm trying to port the Golang implementation of those packages to Dart, but it's quite a huge amount of coding. So it will be awesome to hear that Dart will have packages like that as a part of stdlibs.