verify_gem (Gem::Validator)

    # File lib/rubygems/validator.rb, line 23
        def verify_gem(gem_data)
          raise VerificationError, 'empty gem file' if gem_data.size == 0

          unless gem_data =~ /MD5SUM/ then
            return # Don't worry about it...this sucks.  Need to fix MD5 stuff for
                   # new format
                   # FIXME
          end

          sum_data = gem_data.gsub(/MD5SUM = "([a-z0-9]+)"/,
                                   "MD5SUM = \"#{"F" * 32}\"")

          unless Gem::MD5.hexdigest(sum_data) == $1.to_s then
            raise VerificationError, 'invalid checksum for gem file'
          end
        end