Cross-Platform Encryption?

Dr. Sp0ng asks: "I'm sure a lot of Slashdot readers carry around USB keychain drives or other portable media. What cross-platform encryption solutions have you found for these? The ideal solution would be something which can create a true encrypted disk image in a file, along with Windows and OS X (and perhaps even Linux) standalone executables which can mount these without requiring you to install anything. Obviously something like GnuPG could be used, but it won't let you create an actual mountable filesystem. There are plenty of Windows solutions, and Mac OS X users can simply create an encrypted DMG, but are there any cross-platform solutions out there?"

Comments

A simple solution

[waynegoode]

This is not exactly what you are looking for, but how about ...

A big ZIP file on the drive.

+ It is encrypted.
+ It is cross platform if the underlying File System is.
- The computer needs a ZIP file decrypter and a encrypter if you want read/write.
- It acts like a file system, but really isn't.
- Not the best encryption.

Re:A simple solution

[jasonwea]

And the worst negative of all for me:

Typically one would have to decrypt the files to a local fixed disk where they live unencrypted while you work on them.

Options such as RAM disks exist but how readily available are these? (Think of machines where you do not have root).

Re:A simple solution

[Skuggamara]

I believe ZIP is encryptable with AES-256 now. Wouldn't this be considered "good" encryption?

Re:A simple solution

[Trepalium]

Depends on your ZIP utilty. Winzip's AES encryption != pkzip's AES encryption, and I don't think Linux unzip supports either one yet.

Re:A simple solution

[Trepalium]

Even if you didn't have to decrypt the files to open them, there's a good chance a directly opened file from a compressed volume might make it to the pagefile unencrypted (or to temporary files in %TEMP%). Depends on what risks you're willing to take. If you're just transporting files between trusted machines through untrusted areas, this may be perfectly fine (e.g. USB flash drive on a keychain). If you expect your files to be secure just because they're in an encrypted state on the disk, you might be disappointed.

Re:Truecrypt

[avalys]

Ditto. Truecrypt is great, and free.

They are also coming out with a Linux version in the future, but I don't know of the timeframe.

Unfortunately, an OS X port is not planned.

Encrypted DMG on OS X only supports AES-128

[zhenga]

Altho Disk Utility on OS X can create encrypted disk images, it only has one encryption method which is AES-128.
(prove me wrong here, but i've search many times on google to see if other encryption methods were available)

I once created a 4 GB encrypted sparse disk image, but copying large files to it will always result in an inresponsive OS on my 867MHz G4.

Maybe a fixed sized image will work better, but what I really want is support for other encryption algorythms so the user can make the trade-off between speed and security/paranoid level. I for one would not mind encrypting a disk with Blowfish only.

On Windows I use TrueCrypt, I can't wait to see an OS X port of that (and other platforms ofcourse ;)

Re:It's so obvious!

[thegrassyknowl]

Well, you could XOR your data, or have the disk in EXT2 format (with a small FAT32 partition at the start with EXT2 drivers for various sysems.

As for encryption, I presume you're interested in keeping the average user from sector L out of your files, should your key be "misplaced".

I'd look at GPG; it's roughly PGP compatible. There are the pay for versions of PGP for Windows that can create a big encrypted file and give it a drive letter. Maybe there exists some GPG code that can mount those files?

QEMU?

[kisielk]

I've been thinking about doing a QEMU setup on a flash drive with an encrypted file system, and including QEMU executables for various OSs. You coul d then boot up the QEMU image, which could have networking support with Samba or something, and then access the files over the network.

I haven't actually tried this yet, and I'm not entirely convinced it's a good idea, but it's one suggestion. Has anyone else tried this? Any comments or suggestions?

Previously on Ask Slashdot...

[Bogtha]

A pretty much identical Ask Slashdot from two years ago: Multi-Platform Encrypted Disk Image Formats?

Re:Previously on Ask Slashdot...

[aCC]

A pretty much identical Ask Slashdot from two years ago

Exactly. 2 years is definitely too old.

FreeOFTE for Win/Lin or ccrypt for Mac/Win/Lin

[Trepalium]

FreeOTFE runs in Windows and is compatible with Linux losetup/dm-crypt volumes. The only Win/Mac cross encryption program I've found is ccrypt which is unfortunately just a simple file encryption program.

Embedded Damn Small Linux

[forsetti]

You *have to* check out "Embedded" Damn Small Linux. ~50MB download, extract to your USB key, and run a full blown Linux distro in QEMU (Linux and Windows QEMU included).