Let's cut to the chase right now:
Cracking encrypted disk image, AKA DMG is feasible, but, and there are many buts, is extremely, extremely time consuming.
If you do not remember at all the password, or if you attempt to crack in 'blind mode', you will probably need to teach your kids how to do it: By the time you'll have a fighting chance, you'll be long dead.
Step 1: Write down everything you can remember about the forgotten password, i.e what you could have used, and what you are sure not to have used, i.e. never used a space or a '@' sign.
Step 1a: If you remember enough of your password, or if you are just missing trailing numbers i.e Mypassword???? >> MyPassword1234 and do not remember if it's 1234 or 4321, or 9999, Just use CrowbarDMG and a Wordlist.
For good Wordlists, go here!
If you need to create a specific wordlist (because you remember what you may have used and, most importantly, what you may have not used, go here and look for Wordlists On Demand)
Warning!: CrowbarDMG is slow!
CrowbarDMG is basically a GUI for the hdiutil command
ETA for trying 9999 passwords: About 3 hrs
99,999 passwords: About 30 hrs
999,999 passwords: About 300 hrs Or 12 days ....
Step 2: Do you know how to compile and use John The Ripper? I mean 'use it! including editing Rules, etc?
--> No? Proceed here. Read carefully. Pause. Repeat.
--> Yes! Ok, Sure?
1) Download JTR, version Bleeding Jumbo by Magnum
As of Aug 2013, it's here otherwise here
2) Compile. Don't forget to edit the Makefile and John.conf. Check for CUDA and OMP/MPI RUN. Creating a new Charset? that could be wise...
3) Run dmg2John.py to extract the hash
python [path to file ]dmg2john.py [path to file] myfile.dmg > dmg.txt
4) Edit/Create your rules as needed
5) ./ John etc (Run Baby, run ....)
6) There is always Hashcat (Win/Lin)
7) Because most you have seen, in movies, Hackers cracking an AES within minutes, you'll try without thinking too much about it.
It's going to leave you with a lot of time to read ....
Enjoy ...
8) Without going into too much details, the use of GPU assisted is highly recommended. If you have one of those ones, you'll most likely increase your speed by a factor of 1000, sometimes 10,000 times faster.
How To Crack An Encrypted Dmg Password
☞ Password Cracking AES-256 DMGs and Epic Self-Pwnage
(The Keyword here is: 25 GPU)
☞ 'If you have thought about a new cracking method, It's probably already in JtR'
(Matt Weir) (Quoted liberally)
☞ 'I don't care if the NSA teams up with the KGB, a full random 15Ch long AES is practically unbreakable in a lifetime.
(Matt Weir, Quoted Very Liberally, From circa 2009)
EPAG: Empirical Poke-Around Graph
Markov Probabilities
Jan 12, 2016 Linux:./vfdecrypt -idmg location -k -o.dmg Windows: vfdecrypt -idmg location -k -o.dmg How to decrypt and mount an iOS firmware. Download an iPhone or iPad firmware that matches your simulator version and make sure that there is a VFDecrypt Key by checking the corresponding Build column. TransMac Crack is the best application to open Mac APFS, HFS format disk drives and dmg files from Windows. It also helps you to open flash drives. It also helps you to open flash drives. Further, it also used for CD/DVD/Blu-ray media, HD floppies, dmg part, sparse bundle, and sparse image files.
How To Crack An Encrypted Dmg Download
Simple to set up, seamless to use, fast, safe, secure and maintenance free. It will encrypt data on the fly written to it, decrypt data read from it. HSENCFS uses only storage space for actual data stored, no pre-allocation needed. It is fast enough for real time Video Encryption. HSENCFS is classified as a variable key length encryption. According to the website HFSExplorer can open and read encrypted dmg images. HFSExplorer is an application that can read Mac-formatted hard disks and disk images. It can read the file systems HFS (Mac OS Standard), HFS+ (Mac OS Extended) and HFSX (Mac OS Extended with case sensitive file names). On your desktop you'll see your encrypted DMG file and also the mounted volume that you named above. You can drag the files you want encrypted into this volume, then unmount it. Essential Mac Tips: Protect Files with Encrypted DMG Samuel After learning how to hide the file on the Mac, now there is another trick on how to encrypt files in Mac OS X and set the DMG password.