ballot voting systems allow only a recount of the "stored votes". These "stored votes" might not represent the correct voter intent if the machine has been corrupted or suffered malfunction. A fundamental hurdle in the implementation of paper audit trails is the performance and authority of the audit. Paper audit systems increase the cost of electronic voting systems, can be difficult to implement, often require specialized external hardware, and can be difficult to use. In the United States, 27 states require a paper audit trail by statute or regulation for all direct recording electronic voting machines used in public elections. Another 18 states do not require them but use them either statewide or in local jurisdictions. Five US states basically have no paper trail. In India, the voter-verifiable paper audit trail (VVPAT) system was introduced in 8 of 543 parliamentary constituencies as a pilot project in 2014 Indian general election. VVPAT was implemented in Lucknow, Gandhinagar, Bangalore South, Chennai Central, Jadavpur, Raipur, Patna Sahib and Mizoram constituencies. Voter-verifiable paper audit trail was first used in an election in India in September 2013 in Noksen (Assembly Constituency) in Nagaland. VVPAT along with EVMs was used on a large-scale for the first time in India, in 10 assembly seats out of 40 in 2013 Mizoram Legislative Assembly election. VVPAT -fitted EVMs was used in entire Goa state in the 2017 assembly elections, which was the first time that an entire state in India saw the implementation of VVPAT. voter-verified paper audit trail (VVPAT) system which enables electronic voting machines to record each vote cast by generating the EVM slip, was introduced in all 543 Lok sabha constituencies in 2019 Indian general election. History When a voter casts a vote on a direct-recording voting machine, the voter "has no knowledge through his senses that he has accomplished a result. The most that can be said, is, if the machine worked as intended, then he ... has voted." This observation was made by Horatio Rogers in 1897, and it remains as true with DRE voting machines as it was with the early mechanical voting machines that Rogers spoke about. In 1899, Joseph Gray addressed this problem with a mechanical voting machine that simultaneously recorded votes in its mechanism and punched those votes on a paper ballot that the voter could inspect before dropping it in a ballot box. Gray explained that "in this manner,