Phone Chat Records: Encrypted SQLite and What Survives Deletion
Chat history is a database problem inside a phone-encryption problem. Both have to be solved to read anything.
Storage
Messages live in an app-private SQLite database, encrypted with a key derived from account and device data (SQLCipher on Android; Data Protection classes on iOS). You need the device unlocked and the app data accessible.
After deletion
Deleted rows free pages that may still contain old content; a VACUUM or heavy reuse clears them. Server-side deletions are out of scope — only local residue and backups can help.
FAQ
Is a copied database file readable?
Rarely: it is encrypted. Decryption requires the device context.
What is the fastest path?
Desktop app backups and migration records usually beat lab extraction.