By Seo Jeong Yun WIRED Korea

When the law enforcement agencies launched an investigation into the distribution of explicit and degrading pornography on Telegram last month, not many would have expected they would make a breakthrough anytime soon.

The reason was that all messages were encrypted on the instant messenger app before being stored on its offshore cloud server and, if needed, deleted without leaving any trace. Moreover, the criminal suspects conducted transactions with the use of secure cryptocurrencies.

But it did not take long before they identified one of the masterminds of the digital sex crime, who operated “nth rooms,” or serialized chatrooms, on Telegram for the distribution of dehumanizing photos and videos, by checking on their promotion on other social networking sites.

On March 16, police arrested Cho Ju-bin, 24, on charges of operating the “Baksa” serial chatrooms with paid membership, where digital images, videos and other files of pornography were distributed.

He allegedly blackmailed women, young girls and even minors to carve their names on the skin or engage in other explicit, gruesome acts and, in the meantime, videotape themselves. The content was distributed in the three Baksa chatrooms, whose membership reportedly ranged from 250,000 won to 1.5 million won.

The police investigation found Cho used cryptocurrencies -- Bitcoin, Ethereum and Monero -- to shield their transactions from snooping outsiders. The privacy provided by these cryptocurrencies apparently attracted Cho and other people wishing to evade law enforcement.

But Cho was negligent when he failed to learn about the “know your customer” guidelines, also known as the KYC guidelines, which require financial service providers, including cryptocurrency exchanges, to make efforts to identify those using their services for transactions and, by doing so, assist in the fight against digital crime.

Under the guidelines, cryptocurrency exchanges operating in Korea offered to assist the law enforcement agencies in their investigations into the sex crime scandal involving Cho, Godgod (a transliteration from Korean, which could be spelled Gatgat as well) and other criminal suspects.

The police are tracking down the person using Godgod as his username, who operated another group of serialized chatrooms on Telegram, the “nth rooms.” He went into hiding after handing the operation of the chatrooms over to Watchman.

The man using Watchman as his username and identified by his family name, Cheon, was arrested last November for operating a pornographic site. With the operation of nth chatrooms added to his earlier charges in February, Cheon is now awaiting sentencing in a trial court.

The law enforcement agencies are stepping up their investigation under pressure from tens of thousands of petitioning citizens who demand all culprits be brought to justice. Apparently in response, President Moon Jae-in demands an investigation on those who paid for access to pornographic content as well as the chatroom operators.

Now help is coming from cryptocurrency exchanges. Huobi Korea, the Korea subsidiary of a Singapore-based cryptocurrency exchange, while condemning the operators of the nth and Baksa chatrooms for their unethical behavior, promises to assist in the criminal investigation into the digital sex crime when requested. Similar help has been offered by Coinone, a Seoul-based cryptocurrency exchange.

Those and other exchanges are obligated to help identify those who have conducted cryptocurrency transactions on their sites under not only the international KYC guidelines but the 2013 Korean Act on Reporting and Using Specific Financial Transaction Information. The law has recently been amended to include clauses preventing cryptocurrencies from being used in money laundering and other crimes.

Another encouraging development is reportedly assistance in the investigation by Mega Limited, a New Zealand-based company, which provides cloud storage and file hosting services.

Stephen Hall, chief executive offer of Mega Limited, who doubles as its chief compliance officer, has told the Maeil Business Newspaper that his company is cooperating with the Korean police. He is quoted as saying that his company has no toleration of sexual harassment against children.

The business daily says Mega is expected to provide the police with information on the criminal suspects, ranging from logins to uploads and folder creations.

Those who use Mega’s cloud service to share or trade illegal sexual content will be driven into panic, the business daily says, adding that many Koreans use the service for illegal purposes as they believe few other cloud services are as secure as Mega or Google Drive.

As the dragnet is tightening, some of those suspected of digital sex crime and visitors to pornographic chatrooms are reportedly seeking legal counsel, surrendering themselves to the police or taking their lives in extreme cases.