How does WhatsApp store phone numbers in its databases?

[muskanhossain]

Based on the information available, here's how WhatsApp stores phone numbers in its databases:

WhatsApp stores phone numbers for various purposes, including:

Contact Discovery: When a user grants permission, WhatsApp accesses their device's address book to identify which contacts are also WhatsApp users. For contacts not yet on WhatsApp, their phone numbers are cryptographically hashed and then deleted. These hashes are linked to WhatsApp users who synced the numbers, allowing for efficient connection when those contacts join later. WhatsApp also creates a separate cryptographic hash representation of all phone numbers in the address uae whatsapp number data book to detect and combat misuse of contact syncing.

Saving Contacts to WhatsApp Account: Users can choose to save the names and phone numbers of their WhatsApp contacts to their WhatsApp account. This allows for restoration and management of contacts across devices. Importantly, the phone numbers of contacts who do not use WhatsApp are not included in this saved list.
Account Identification: The phone number is a fundamental identifier for a WhatsApp account. When a user registers, their phone number is associated with their WhatsApp profile.
Facilitating Communication: Phone numbers are essential for connecting users with each other on the platform.
Database Structure (Android Forensics):

Forensic analysis of WhatsApp on Android devices reveals that phone numbers are stored in specific databases:

wa.db: This database contains a full list of the WhatsApp user's contacts, including phone numbers, display names, timestamps, and other registration information. The wa_contacts table within this database holds details like contact ID, status, display name, and timestamps.

msgstore.db: This database stores information about sent messages, including the contact number associated with the message. The messages table contains details like the contact number, message body, status, and timestamps.

Other files like registration.RegisterPhone.xml also contain information about the phone number associated with the WhatsApp account.
Security Measures:

WhatsApp implements several security measures to protect phone numbers:

Cryptographic Hashing: As mentioned, non-WhatsApp contact numbers from synced address books are hashed to prevent identification.
Encryption: While the content of messages is end-to-end encrypted, the databases storing phone numbers on devices are also subject to encryption. WhatsApp also offers end-to-end encrypted backups for chat history on Google Drive and iCloud.
Privacy Settings: Users have control over who can see their profile photo and "About" info, which are linked to their phone number.
Two-Step Verification: This feature adds an extra layer of security to a WhatsApp account by requiring a six-digit PIN when registering the number on a new device, in addition to the SMS code.
It's important to note that while WhatsApp encrypts message content, metadata, which includes the phone numbers of communicating parties, is generally not encrypted in the same way.c