Sharing Delta Chat contact using voice or pen and paper

[ian]

TL;DR Print the invite QR and minimized i.delta.chat link on your business card or on a regular sheet of paper cut up to small slices. The recipient of such a card can either scan or type it in at home. No theoretical decentralized alternative could provide you a way to remember it and spell it out over the phone, because any such scheme would preferably require sharing at least 256 bits of entropy (43 random characters in base64 or 52 in more “easily” remembered base32). Even a toy scheme would require 128 bits that is already out of reach.

See also problems with centralized alternatives and other issues this is a duplicate of:

Invite URL questions [delete name, shorten, nick-based discovery, business card]

Yes, you can cut off the name, but your peer will see your name again after joining. So, you should preferably pick a name that is not compromising for you in the first place when creating a throw away profile for invitations. Shortening the invite link would defeat the whole purpose of providing cryptographic material out of band. Centralized usernames would defeat the purpose of the decentralized nature of DC, open up a centralized actor to metadata collection and could MITM and deny people …

Discover mutuals

In that case, this is a duplicate of the following:

Contacts only option for who can message you, prevent block evasion from groups

@jase Your phrasing seems overly verbose and vague, but let me see whether I understand what you want: I have joined a public group of untrustworthy strangers. Then one of the participants started harassing and stalking me. What should I do? You should delete the profile, create a new one and join the group with that (or just join other groups instead). In general, you should only participate in untrustworthy groups and contact untrustworthy individuals with a throw-away profile. The threat…