Original sentence: A fundamental hurdle in the implementation of paper audit trails is the performance and authority of the audit.Nonetheless, many districts require a paper audit trail by statute for all electronic direct record voting machines used in public elections.Paper audit systems increase the cost of electronic voting systems, can be difficult to implement, and often require specialized external hardware which some contend is difficult to use
Edited sentence: A fundamental challenge with paper audit trails is the performance and authority of the audit.However, despite the challenges, many states are requiring a paper audit trail by statute for all electronic direct record voting machines used in public elections.In addition, paper audit systems are expensive, difficult to implement, and often require specialized external hardware not easily usable by voters and election judges