Police in the Netherlands and Belgium have shut down an encrypted messaging app and arrested criminals after successfully cracking the encryption used by the app.

The app in question goes by the name of Sky ECC made by Sky Global Inc. and is claimed to have become popular with criminals since it launched two years ago. The website for the app is still up, with claims that it’s “the most secure messaging platform money can buy” and “some call it unhackable.”

Those behind the app were so confident of its encryption that they offered a $5 million reward to anyone who can defeat it.

Prior to being shut down, Sky ECC is said to have more than 70,000 customers who could install the app on Android, BlackBerry and iPhone devices and also included a “panic button” to erase all of its content in case of emergency or arrest.

Sky ECC’s encryption is reported by De Standaard to have been successfully cracked by investigators at the end of last year, allowing them to sort through thousands of messages criminals were sending to each other. The information gained was then used to make arrests on Tuesday, March 9. Some 48 criminals were arrested by about 1,500 police in coordinated raids in Belgium, and 30 arrests made in raids on 75 homes in the Netherlands. The Record reported that there are more arrests to come.

Along with the arrests, police in both countries uncovered a network of laboratories where crystal methamphetamine and other drugs were being produced. An additional 8,000 kilograms of cocaine with an estimated value of €20 million ($23.76 million) was also seized.

The information gained from the investigation will also be shared with other countries since the app is also used in other parts of Europe and the U.S.

It’s not clear from reports what if any arrests were made when it comes to the operators of Sky ECC, although servers were seized. Encrypted apps are not illegal in the European Union, but unlike in the U.S., there are no strong liability protections when services are used for illegal purposes such as with Section 230 of the Communications Decency Act.

If U.S. messaging and social media companies were held liable for illegal use, Twitter Inc. in particular would be in major trouble given that it’s a hub for the distribution of child pornography.

Image: Sky ECC