I wanted to have a play with Scala, so I installed the version that comes with Debian - 2.9.2.
However, this version doesn't work with Java 8 - apparently 2.12 is the version that will work with Java 8.
So I remove the Debian version, and head over to scala-lang.org.

http://www.scala-lang.org/download/ has the downloads, but:

a: No HTTPS
b: No checksums
c: No GPG key

(It is possible to change the default HTTP download from http://downloads.typesafe.com/ to https.)

In 2016, downloads should be signed.

For what it's worth, here are the checksums for the file I downloaded.

MD5 dc95937bb2768caf5397195282e497e1  scala-2.12.0-M5.deb
SHA1 9bce1ad9fba780ef4da92496bcd06cdd799d616e  scala-2.12.0-M5.deb