The arrests came amid ongoing efforts by the U.S. and its allies to limit the use of technology manufactured by firms with ties to Beijing over espionage concerns.

Jan Schürlein, a 19-year-old IT developer, says he is being treated as a "witness" in the investigation into the breach, which exposed information about hundreds of Germany's politicians.

European electronics and telecom retailer Dixons Carphone said a breach of its systems last year could have resulted in attackers accessing roughly 10 million records, including customers’ personal data.

On June 20, German police raided homes and offices for the group Zwiebelfreunde (translated as Onion Friends), an organization affiliated with the Torservers.net group, which runs servers for the Tor anonymity network.

The European Central Bank (ECB) wants to make penetration testing a regular practice.

Some privacy provisions in GDPR could have a negative effect on security researchers' work.