Doxing is the process of publishing private or identifying information, such as the name, residential address and contact details, of an individual, for the purpose of permitting or facilitating harassment, intimidation and acts of violence towards this person & their family. Make this illegal.
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Doxing someone, exposes the individual and their family to and facilitates, mob justice / "vigilante action" This behaviour is unacceptable in a free society, as it discourages the rule of law and encourages anarchy.
GDPR provides some protection but does not address deliberate and malicious acts of leaking personally identifiable information. This should be a specific crime where the perpetrators upon guilty verdict receive a mandatory 10-year custodial sentence.