Recommendation 13 (Electronic Voting) Netherlands 2006
http://aceproject.org/ero-en/regions/europe/NL/netherlands-elections-assessment-mission-report/at_download/file
Voting system standards should not permit the use of systems which depend for their
security on the secrecy of any part of their technical specifications. Reliance on
proprietary systems should be reduced, where neither citizens, nor electoral officials,
nor observers can determine how they operate.