Good point, sorry for not being precise. By secure, I mean the Confidentiality aspect of the CIA-triplet (Confidentiality, Integrity, Availability) here: that

Good point, sorry for not being precise. By secure, I mean the Confidentiality aspect of the CIA-triplet (Confidentiality, Integrity, Availability) here: that only those person can read the data stored in the encrypted DMG, who has the correct passphrase (which is long and complex enough, and contains sufficient entropy, of course). So any implementation weaknesses (incorrect IV initialisation of the AES-XTS, or anything like that) or other security vulnerabilities which would harm the confidentiality of the container would be interesting to me.