Encrypted database file created and used by WhatsApp Messenger, a messaging application for Android devices. It contains an encrypted database of chat history messages. CRYPT9 files are located on the SD card of Android devices.

The "crypt9" extension is one of many "crypt" extensions such as "crypt6", "crypt7", and "crypt8". The extension is often appended to a .DB file to create the db.crypt9 file, which is used by WhatsApp to secure a user's message database on his or her Android device. For each new installment, the application uses a different algorithm to encrypt the DB files. The extension appended to the DB file, such as .CRYPT7 or .CRYPT8, signifies the algorithm. CRYPT9 database files are located in the following directory: /sdcard/WhatsApp/Databases