It seems that it is not possible to create SHA hashes on Android.
When the attached application is run on Windows (simulator) or iOS, the output is:
[:Instance, :Class, :Base, :MD5, :SHA1, :SHA256, :SHA384, :SHA512]
(iOS could miss the :MD5, don't know for sure, SHA is at least included)

But on Android I just get:
[:Class, :Instance]

So a statement like:
Digest::SHA1.hexencode( "hash this" )
Will fail on Android.

I'm I missing something or is Ruby's Digest::SHA1 just not available on Android?