The law that requires Internet users to use their real names when submitting posts online during election campaigns is appropriate, the Constitutional Court ruled Thursday.
A clause in the Election Law forces people to submit their real names when expressing opinions in support of or in opposition to political parties or candidates on websites of media companies or bulletin boards of portals during campaign periods.
Website operators violating this are subject to fines of up to 10 million won.
In a five to four decision, the justices said the measure is needed to help guarantee fair elections and prevent false and unverified information from spreading rapidly without countermeasures to control it.
"It is highly likely that people may believe information shared on media websites and bulletin boards of portals is credible. Election results might be greatly affected by those who maliciously spread false information with the intention of manipulating the public," the court said.
"Lifting the measure might result in smear campaigns, which would hurt society," it added.
The court added that the law does not infringe on freedom of speech or privacy because no personal information other than names is revealed.
The ruling follows a petition in 2013 by Daum Kakao, formerly known as Daum Communications, which refused to pay a 10 million won fine imposed by the National Election Commission (NEC) for failing to prevent people from posting comments about an election under their real names.
However, there is controversy over how the law is enforced inconsistently, because using real names online is not required from citizens outside of election campaign periods.
In a separate ruling in 2012, the court ruled that a law obliging real names for all postings at all times was unconstitutional, saying it infringes on citizens' privacy and freedom of speech.
After that ruling, Internet users have been allowed to post their opinions using multiple online ids outside of election campaign periods.