I’ve released gem for making MD5/SHA1 hashes in RubyMotion. It’s handled by small ObjC code in vendor directory. You can get this gem from my github.

Add gem ‘rm-digest’  into your Gemfile , run bundle install  and you can generate MD5/SHA1 in your application.

digestSHA1String = RmDigest::SHA1.hexdigest('some string')

digestMD5String = RmDigest::MD5.hexdigest('some string')