Cho Ju-bin, the South Korean mastermind of an online sex blackmail ring, had his sentence of 42 years in prison affirmed Thursday.

The Supreme Court on Thursday confirmed the Seoul High Court’s ruling in June on Cho, 25, who was indicted early last year on 14 charges, including operating a criminal organization, violating laws made to protect minors from sexual abuse, blackmail and committing fraud.

Cho will be banned from employment at institutions or firms that serve children, adolescents and disabled people for 10 years after finishing his prison term, while his personal information will be public for the same period.

He will also be required to wear an electronic bracelet for 30 years and pay a forfeiture of 100 million won ($84,400).

The sex blackmail ring mastermind was accused of working with 38 accomplices from May 2019 to February 2020 to blackmail 74 women and girls, 16 of whom were underage, into filming sexually abusive content. The videos were then sold to members of “Baksabang,” a chat room on messaging app Telegram.

The prosecution has argued that the group Cho ran was not a simple gathering made to share sexual content, as he and his accomplices divided jobs for the purpose of committing crimes and observed self-made internal rules.

The Seoul Central District Court sentenced Cho to 40 years in prison in November 2020 for his crimes and added five more years to his prison term in February for concealing profits in cryptocurrency equivalent to 108 million won.

Prosecutors initially demanded the Seoul Central District Court sentence Cho to life imprisonment, considering the unprecedented graveness of his crimes. Lawyers for the victims told reporters that Cho was not initially apologetic when he was undergoing investigation.

“Thank you for putting a brake on the life of a devil that could not be stopped,” Cho said in front of the press in March last year after being questioned by the police. He was criticized at the time for sounding unapologetic and detached while he spoke.

Yet his 45-year prison term was cut by three years in the appeals court in consideration of Cho coming to a compromise with some of the victims in the case. That Cho did not have a criminal record beforehand was also considered.

In Thursday’s ruling, the Supreme Court also confirmed a 13-year prison term for four of Cho’s accomplices, including a former civil servant. The court approved prison terms of up to eight years for two members of Baksabang.

Chances remain for Cho’s prison term to be extended, as he was separately indicted in April for working with another accomplice to blackmail 18 other female victims, seven of them underage, into producing sexual content for distribution and sale through Baksabang.

Cho’s case came as a huge shock to South Korean society when it was uncovered last year, prompting authorities to discuss levying heavier penalties for digital sex crimes. It was the largest digital sex exploitation case to be revealed in the country by far.

It prompted officials to prepare tougher measures against such crimes and those involved, ranging from producers and distributors to even buyers, advertisers and those in possession of the content shared in the group.

A legislative revision took effect in September to allow police investigators to go undercover when investigating online sex crimes against minors if backed by a court warrant. The National Police Agency chose 40 investigators to carry out the secretive duty, with more later to be dispatched.

The bill was introduced in light of Cho’s case, as it was found that most of Cho and his accomplices’ criminal activities were done secretively through encrypted messaging applications.