Neither is necessary. Vexl doesn’t see your contacts or your phone number.

You also don’t need a random SIM as it completely breaks the reputation model. It makes it a lot harder for you to succeed and find good trades that are actually based on trust. 

Vexl is social graph so trading with friends and friends and friends only. 

It’s also really important to note that Vexl doesn’t have a wallet it doesn’t touch bitcoin or doesn’t touch Fiat. No trading happens on the Vexl app.  It simply connects you with the people in your social graph your real world, web of trust.

It is fully open source. Nonprofit.

I recommend checking out this blog  https://vexl.it/post/understanding-vexl-security-privacy-and-building-a-web-of-trust 

 Thank you for sharing.