Partitions.xml

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Contents 1 Sample file 2 Schema 3 Notes 4 Audit Steps

Sample file

<electionSpecification version="0.1">
	<electionInfo id="PunchScanCounty">
		<sections>
			<section id="0">
				<questions>
				<question id="0" partitionNo="0"/>
				<question id="1" partitionNo="1"/>
				<question id="2" partitionNo="2"/>
				<question id="3" partitionNo="3"/>
				</questions>
			</section>
		</sections>
	</electionInfo>
</electionSpecification>

Schema

• element question

This element has been previously defined however this file adds a new attribute, partition, to the element. A partition is a set of questions to be tallied independent of the other questions. By default, each question should be given its own partition. Questions in the same partition may be necessitated in unusual circumstances (instant run-off, for example) but should be justified by the election authority.

Notes

Partitions prevent voter selections on one question from being correlated to their selections on a different question in the published data. This can help combat attacks where voters encode a unique pattern into their ballots to identify them (an Italian attack). While partitions do not necessarily prevent pattern-based attacks, they ensure the patterns must be encoded within the questions in a single partition. If each question is given its own partition and is scored using plurality, these attacks are eliminated.

Audit Steps

Assuming this file has just become available, what audits are now possible using this file and previous files?

• Audit should check if multiple questions are in the same partition. A warning, not an error, should be output if the check is positive.

• Audit should check if the number of questions are the same as the number of questions defined in ElectionSpec.xml. An error should be output if the check is negative.