1987 Constitution of the Philippines
Section 2. The Congress shall provide a system for securing the secrecy and sanctity of the ballot as well as a system for absentee voting by qualified Filipinos abroad.
The Congress shall also design a procedure for the disabled and the illiterates to vote without the assistance of other persons. Until then, they shall be allowed to vote under existing laws and such rules as the Commission on Elections may promulgate to protect the secrecy of the ballot.