Re: FileVault on other than home directories on MacOS?
Ivan Krsti wrote: TrueCrypt is a fine solution and indeed very helpful if you need cross-platform encrypted volumes; it lets you trivially make an encrypted USB key you can use on Linux, Windows and OS X. If you're *just* talking about OS X, I don't believe TrueCrypt offers any advantages over encrypted disk images unless you're big on conspiracy theories. Note my information may be out of date. I believe that MacOS native encrypted disk images (and thus FileVault) uses AES in CBC mode without any integrity protection, the Wikipedia article seems to confirm that is (or at least was) the case http://en.wikipedia.org/wiki/FileVault There is also a sleep mode issue identified by the NSA: http://crypto.nsa.org/vilefault/23C3-VileFault.pdf TrueCrypt on the other hand uses AES in XTS mode so you get confidentiality and integrity. -- Darren J Moffat - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to majord...@metzdowd.com
Re: FileVault on other than home directories on MacOS?
In Disk Utility - New Image, select size, properties and encryption type (AES 128 or 256) and Create. Then mount and use your encrypted disks as needed. Just as an aside: on 10.5 and upwards I have taken to using encrypted sparse bundles rather than simple images; the advantage of doing this is that if you are creating a encrypted filesystem on (say) a 16Gb FAT-32 USB stick, then: a) you are not constrained to a 4Gb encrypted image (otherwise to FAT32) b) when using the sparse image, your files can be 4Gb c) you do not eat the entire stick all at once d) there can be (is?) a degree of garbage collection e) the stick is still usable as FAT32 - alec -- alec.muff...@gmail.com http://www.crypticide.com/dropsafe/ - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to majord...@metzdowd.com
Re: FileVault on other than home directories on MacOS?
On Sep 21, 2009, at 3:57 PM, Steven Bellovin wrote: Is there any way to use FileVault on MacOS except on home directories? I don't much want to use it on my home directory; it doesn't play well with Time Machine (remember that availability is also a security property); besides, different directories of mine have different sensitivity levels. According to an Apple security person who spoke here about a year ago, you can use the underlying CLI to do everything FileVault does, but at some other point(s) in the directory tree than home directories. - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to majord...@metzdowd.com
QNAP backdoor
http://www.securityfocus.com/archive/1/506607 Overview: The premium and new line of QNAP network storage solutions allow for full hard disk encryption. When rebooting, the user has to unlock the hard disk by supplying the encryption passphrase via the web GUI. However, when the hard disk is encrypted, a secondary key is created, added to the keyring, and stored in the flash with minor obfuscation. Additional Weaknesses: The backdoor key is generated by rand() calls. As the rand() function produces random numbers unsuitable for cryptographic keys. The cryptographic strength of this generated key is approx 2^32, hence feasible for breaking. This would make access to the flash unnecessary. Original Vendor FUD: The functionality for encryption the hard disk does not include a crypto backdoor. (in response to a user question why two keyslots are allocated, and if this is because of a backdoor) -- Regards, ASK - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to majord...@metzdowd.com
Re: FileVault on other than home directories on MacOS?
On 22/09/2009 14:57, Darren J Moffat wrote: There is also a sleep mode issue identified by the NSA: An extremely minor point, that looks like Jacob and Ralf-Philipp perhaps aka nsa.org, rather than the NSA.gov. Still useful. iang - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to majord...@metzdowd.com
Re: FileVault on other than home directories on MacOS?
On Sep 22, 2009, at 5:57 AM, Darren J Moffat wrote: There is also a sleep mode issue identified by the NSA Unlike FileVault whose keys (have to) persist in memory for the duration of the login session, individual encrypted disk images are mounted on demand and their keys destroyed from memory on unmount. TrueCrypt on the other hand uses AES in XTS mode so you get confidentiality and integrity. XTS certainly doesn't provide cryptographic integrity. It provides different ciphertext malleability characteristics than CBC, in that you can only randomize an arbitrary 16-byte block of plaintext instead of being able to flip an arbitrary bit (and screw up the previous block). However, this comes with other costs inherent to seekable narrow-block encryption, so I think it's hard to argue XTS provides more integrity than CBC. Or were you referring to something else? -- Ivan Krstić krs...@solarsail.hcs.harvard.edu | http://radian.org - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to majord...@metzdowd.com
