Facebook CEO Mark Zuckerberg uses Signal App, reveals security expert Dave Walker
Zuckerberg’s phone number was among the leaked data of 533 Mn Facebook users
Besides contact number, data like his name, marriage details, DOB, location and Fb ID were also leaked
Dave says Zuckerberg uses Signal with this number
The news comes at a time when Fb-owned WhatsApp faces backlash over its privacy policy
The Signal app recently overtook WhatsApp in terms of downloads and user base
