The mounting passwords are only stored in encrypted form (on all platforms)!
Windows: the stored password is encrypted using the Data Protection API (DPAPI). Decryption is only possible if logged in with your Windows account. The encrypted password (and other settings) are stored in the AppData folder within your Windows account.
On Windows 7: C:\Users\<YourName>\AppData\Local\Acomba_UG_(haftungsbeschr\BoxCryptor.exe_Url_.....\user.config
Android: the stored password is encrypted using AES-256 with a randomly generated key.
iOS: The password is stored in the (encrypted) Keychain of the device.
Hope I could help you!