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Contacts

Contacts are people you can message directly. This guide covers understanding your identity, sharing it with others, and managing your contact list.

Your Identity

What Identifies You

In Mycel, you're identified by a cryptographic key pair, not a phone number or email:

Component Description Shareable?
Public Key Your identity that others see Yes
Private Key Secret key for signing/decrypting Never
Device UID Short ID derived from public key Yes
MycTag Human-readable fingerprint Yes

Finding Your Identity

  1. Open Mycel
  2. Go to Settings
  3. Tap Profile or your avatar
  4. View your:
  5. QR code (for easy sharing)
  6. Device UID (short and full hex)
  7. Public key fingerprint
  8. Display name

Understanding UIDs

Your Device UID is a unique identifier:

  • Short form: 10-12 characters, easier to share verbally
  • Full hex: Complete identifier for technical use

Example: LH6nQx... (short) or 4c48366e51782e... (full)

Sharing Your Identity

Via QR Code

The easiest way to share:

  1. Go to Settings > Profile
  2. Your QR code is displayed
  3. Have the other person scan it with Mycel

The QR code contains:

  • Your public key
  • Your display name
  • Optional: location hint

Via Copy/Paste

  1. Go to Settings > Profile
  2. Tap Copy next to your UID
  3. Send via any messaging app
  4. Recipient enters the UID manually in Mycel

Via System Share

  1. Go to Settings > Profile
  2. Tap Share
  3. Choose any app (text, email, etc.)
  4. Your contact info is shared as text

Adding Contacts

Scanning a QR Code

  1. Open Mycel
  2. Go to Contacts tab
  3. Tap the QR scanner icon
  4. Point your camera at their QR code
  5. Contact is added automatically

After scanning:

  • Their info appears in your contacts
  • You can immediately start a conversation

Manual Entry

If you received a UID via text:

  1. Go to Contacts tab
  2. Tap Add Contact or +
  3. Enter their Device UID
  4. Optionally add a nickname
  5. Tap Save

Verify the UID

Make sure you've entered the UID correctly. A typo means messages go nowhere.

Contact Discovery

Automatic Discovery

When you're near other Mycel users:

  1. Devices detect each other via Bluetooth/Wi-Fi
  2. Public profiles are exchanged
  3. New contacts appear in your list with a badge

You don't need to explicitly add nearby users - they're discovered automatically.

Discovery vs Contacts

Discovered Peers Saved Contacts
Added automatically Yes No
Persist after leaving range Temporarily Yes
Can message Yes Yes
Shows in Contacts Yes (as neighbors) Yes

New Contact Badge

When new contacts are discovered:

  • A badge appears on the Contacts tab
  • New contacts are highlighted in the list
  • Badge clears when you view the contacts

Managing Contacts

Viewing Contact Profiles

  1. Go to Contacts
  2. Tap a contact's name or avatar
  3. View their profile:
  4. Display name
  5. Device UID
  6. Public key fingerprint
  7. Last seen time
  8. Online status

Renaming Contacts

You can set a local nickname that only you see:

  1. Open the contact's profile
  2. Tap Rename or the edit icon
  3. Enter your preferred name
  4. Save

The nickname:

  • Only appears on your device
  • Doesn't change their actual name
  • Helps you identify contacts

Contact Status

Status Meaning
Online Connected within last 15 seconds
Offline Not currently connected
Last seen Time of last connection

Searching Contacts

In the Contacts tab:

  1. Use the search bar at the top
  2. Search by:
  3. Name/nickname
  4. Device UID
  5. Fingerprint

Starting Conversations

From Contacts

  1. Go to Contacts
  2. Tap a contact
  3. Tap Message or the chat icon
  4. Start typing

From Contact Profile

  1. Open the contact's profile
  2. Tap Start Chat or Message

Quick Actions

  • Long-press a contact for quick actions
  • Swipe for common operations (varies by device)

Contact Sync

How It Works

Contact information syncs through the mesh:

  1. When you meet someone, profiles are exchanged
  2. Profile updates (name changes) propagate
  3. Deleted contacts stay deleted locally

What Syncs

  • Display names
  • Public keys
  • Optional location hints
  • Profile sequence numbers

What Doesn't Sync

  • Your local nicknames
  • Message history
  • Contact groupings/organization

Privacy

What Contacts See About You

When you're nearby, others can see:

  • Your display name
  • Your Device UID
  • Your public key
  • That you're running Mycel
  • Approximate location (you're "nearby")

What You Control

  • Display name - Set whatever you're comfortable sharing
  • Full name - Optional, can leave blank
  • Location sharing - Opt-in for geo-routing (city-level, not precise)

Recommendations

  1. Use a nickname - Don't use your real name if privacy-conscious
  2. Review settings - Check what you're sharing in Profile settings
  3. Be aware - Nearby discovery means strangers know you're there

Troubleshooting

"Contact not found"

  • Check the UID - Make sure you entered it correctly
  • Check connectivity - You may need to be in range first
  • Try scanning QR - More reliable than manual entry

"Can't scan QR code"

  • Check camera permission - Mycel needs camera access
  • Improve lighting - QR codes need good visibility
  • Hold steady - Keep the phone still while scanning
  • Check distance - Not too close, not too far

"Contact shows offline"

  • They may not be nearby - Offline is normal when not in range
  • Check your connectivity - Go to Mesh Lab > Nearby
  • Be patient - Status updates when you reconnect

"I accidentally added wrong contact"

  • You can remove contacts from your list
  • Find them in Contacts, open profile, look for Remove/Delete option
  • Message history remains but is archived

"Duplicate contacts"

Can happen if someone:

  • Reinstalled the app (new identity)
  • Has multiple devices

Each device generates a unique identity, so the same person on two devices = two contacts.

Contact List Organization

Pinning Conversations

Important contacts can be pinned:

  1. Go to Chats > Direct Messages
  2. Swipe right on a conversation
  3. Tap Pin

Pinned conversations stay at the top.

Archiving Conversations

To hide inactive conversations:

  1. Swipe left on a conversation
  2. Tap Archive

Archived conversations move to the Archive tab.

Finding Archived Contacts

  1. Go to Chats
  2. Tap Archived tab
  3. View and restore as needed

Technical Details

Key Types

Key Algorithm Purpose
Identity Ed25519 Signing, authentication
Encryption X25519 Key agreement for DMs

Profile Data

Each contact profile includes:

  • Public key (Ed25519)
  • Display name
  • Full name (optional)
  • Device label
  • Location hint (H3 cell, optional)
  • Profile sequence number
  • Last updated timestamp

Deep Dive: Keys & Cryptography

Next: Messaging | Settings | Groups