TweetFollow Us on Twitter

Safeguarding "sensitive data" using encrypted disk images

Volume Number: 22 (2006)
Issue Number: 4
Column Tag: Programming

Safeguarding "sensitive data" using encrypted disk images

by Aaron Adams

With Tiger's release, it's now easier than ever to keep your (imagine me making big finger quotes here) "sensitive data" secure. You know the "sensitive data" I'm talking about. The kind that's not intended for casual viewing. There's also the real sensitive data. Payroll records, bonus charts, proprietary data, your secret plan for world peace. It's only a matter of time until someone using a shared Mac performs an innocuous Spotlight search that suddenly turns up a cornucopia of sensitive data associated with you. Depending on who finds it, you could lose your job, lose business, lose your significant other, or just have more headaches than you really need. An ounce of prevention is worth a ton of cure.

Hiding such things from Spotlight is a good idea. To do that, you can create an encrypted disk image that is password protected to keep nosy users out. The contents of the image won't appear in Spotlight unless the image is mounted.

To begin, go to the /Applications/Utilities folder (press command-shift-u in the Finder) and start up Disk Utility. Click File, New, and Disk Image from Folder. This will create something called a sparse image. Sparse images are initially only as big as the data they contain, but have the advantage of expandability later.

Select the folder where your sensitive data is located and press the Image button. Name the image. Select read/write from the Image Format drop-down. Click the Encryption drop-down and choose AES-128 (recommended). Select a save location and press Save.

You will then be prompted for a password. This is the password Disk Utility will use to encrypt the data and that you will have to enter it each time the image is mounted. Do yourself a favor and make the password hard to guess. Do yourself another favor and uncheck the box marked Remember password (add to Keychain). It defeats the purpose of encrypting and password protecting an image if you're going to automate its access with Keychain. Click OK after entering your new password. [Ed Note: Do yourself a final favor - make this password something different than your login password.]

A new disk image containing your data in encrypted form will be created. When you double-click the image to mount it, you will be prompted for the password. Drag and drop new sensitive data onto the image as desired for permanent safekeeping.

Over time, your collection will probably continue to grow and will become larger than the sparse image you just created. As I said before, sparse images can be expanded to any size you need, but the drawback is that you have to do it through the command line.

Open Terminal and enter this command:

hdiutil resize -size xxx /path/to/image.dmg

where xxx is the size you want to the image to be in megabytes or gigabytes. For example, 500mb or 4.7gb.

Now your sensitive data, or "sensitive data", is protected from prying eyes and accidental finds. Backups are a simple one-file copy operation. You stay out of trouble, off the unemployment lines, and in the closet. I love it when technology helps people.


Aaron Adams is a Mac consultant and network whipping boy located in Dayton, Ohio. You may also remember him from Apple's "Switch" campaign a few years ago. You can e-mail him at aaron@aaronadams.net.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Latest Forum Discussions

See All

Combo Quest (Games)
Combo Quest 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: Combo Quest is an epic, time tap role-playing adventure. In this unique masterpiece, you are a knight on a heroic quest to retrieve... | Read more »
Hero Emblems (Games)
Hero Emblems 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: ** 25% OFF for a limited time to celebrate the release ** ** Note for iPhone 6 user: If it doesn't run fullscreen on your device... | Read more »
Puzzle Blitz (Games)
Puzzle Blitz 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Puzzle Blitz is a frantic puzzle solving race against the clock! Solve as many puzzles as you can, before time runs out! You have... | Read more »
Sky Patrol (Games)
Sky Patrol 1.0.1 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0.1 (iTunes) Description: 'Strategic Twist On The Classic Shooter Genre' - Indie Game Mag... | Read more »
The Princess Bride - The Official Game...
The Princess Bride - The Official Game 1.1 Device: iOS Universal Category: Games Price: $3.99, Version: 1.1 (iTunes) Description: An epic game based on the beloved classic movie? Inconceivable! Play the world of The Princess Bride... | Read more »
Frozen Synapse (Games)
Frozen Synapse 1.0 Device: iOS iPhone Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Frozen Synapse is a multi-award-winning tactical game. (Full cross-play with desktop and tablet versions) 9/10 Edge 9/10 Eurogamer... | Read more »
Space Marshals (Games)
Space Marshals 1.0.1 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.1 (iTunes) Description: ### IMPORTANT ### Please note that iPhone 4 is not supported. Space Marshals is a Sci-fi Wild West adventure taking place... | Read more »
Battle Slimes (Games)
Battle Slimes 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: BATTLE SLIMES is a fun local multiplayer game. Control speedy & bouncy slime blobs as you compete with friends and family.... | Read more »
Spectrum - 3D Avenue (Games)
Spectrum - 3D Avenue 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: "Spectrum is a pretty cool take on twitchy/reaction-based gameplay with enough complexity and style to stand out from the... | Read more »
Drop Wizard (Games)
Drop Wizard 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Bring back the joy of arcade games! Drop Wizard is an action arcade game where you play as Teo, a wizard on a quest to save his... | Read more »

Price Scanner via MacPrices.net

13-inch M4 MacBook Airs on sale for $150 off...
Amazon has new 13″ M4 MacBook Airs on sale for $150 off MSRP right now, starting at $849. Sale prices apply to most colors and configurations. Be sure to select Amazon as the seller, rather than a... Read more
15-inch M4 MacBook Airs on sale for $150 off...
Amazon has new 15″ M4 MacBook Airs on sale for $150 off Apple’s MSRP, starting at $1049. Be sure to select Amazon as the seller, rather than a third-party: – 15″ M4 MacBook Air (16GB/256GB): $1049, $... Read more
Amazon is offering a $50 discount on Apple’s...
Amazon has Apple’s 11th-generation A16 iPads in stock on sale for $50 (or a little more) off MSRP this week. Shipping is free: – 11″ 11th-generation 128GB WiFi iPads: $299 $50 off MSRP – 11″ 11th-... Read more
Clearance 13-inch M1 MacBook Airs available f...
Walmart has clearance, but new, Apple 13″ M1 MacBook Airs (8GB RAM, 256GB SSD) available online for $649, $360 off original MSRP, in Space Gray, Silver, and Gold colors. These are new MacBooks for... Read more
iPad minis on sale for $100 off Apple’s MSRP...
Amazon is offering $100 discounts (up to 20% off) on Apple’s newest 2024 WiFi iPad minis, each with free shipping. These are the lowest prices available for new minis among the Apple retailers we... Read more
AirPods Max headphones on sale for $479, $70...
Amazon has AirPods Max with USB-C on sale for $479.99 in all colors. Shipping is free. Their price is $70 off Apple’s MSRP, and it’s the lowest price available today for AirPods Max. Keep an eye on... Read more
14-inch M4 Pro/M4 Max MacBook Pros on sale th...
Don’t pay full price! Get a new 14″ MacBook Pro with an M4 Pro or M4 Max CPU for up to $320 off Apple’s MSRP this weekend at these retailers…they are the lowest prices available for these MacBook... Read more
Get a 15-inch M4 MacBook Air for $150 off App...
A couple of Apple retailers are offering $150 discounts on new 15″ M4 MacBook Airs this weekend. Prices at these retailers start at $1049: (1): Amazon has new 15″ M4 MacBook Airs on sale for $150 off... Read more
Unreal Mobile is offering a $100 discount on...
Unreal Mobile, an MVNO using AT&T and T-Mobile’s networks, is offering a $100 discount on any new iPhone with service. This includes new iPhone 16 models as well as iPhone 15, 13, and SE phones... Read more
16-inch M4 Pro MacBook Pros on sale for $250-...
Don’t pay full price! Amazon has 16-inch M4 Pro MacBook Pros (Silver or Black colors) on sale right now for up to $300 off Apple’s MSRP. Shipping is free. These are the lowest prices currently... Read more

Jobs Board

All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.