Christopher Käck

less info
73 reputation
19
bio website blog.kejsarmakten.se
location Malmö, Sweden
age 25
visits member for 2 years, 4 months
seen Feb 13 at 8:57

Newly graduated MSc in Computer Science from the University of Lund. Currently working on my own startup and with a machine learning project for FEO Media (Quizkampen).

Feel free to send me an email!


Jan
10
awarded  Notable Question
Nov
9
awarded  Commentator
Nov
9
comment Is it reasonably safe to use PIN code for encryption?
@LieRyan They still share password undependant of the encryption scheme used for the disc encryption. The problem is that users will not choose a long passphrase if they also need to use the same long passphrase to simply unlock the screen. Which I am -very- convinced is unsafe. So what can the reason be that the user is forced to use the same passcode for both features? Some limitation in the OS?
Nov
8
comment Is it reasonably safe to use PIN code for encryption?
I will follow that request. Thanks!
Nov
8
comment Is it reasonably safe to use PIN code for encryption?
@lie_ryan Well, the question I was looking for was rather a android-y/software-dev reason why they would share password for the different tasks. I know that it is unsafe to use 4 digits as a disc encryption password.
Aug
11
awarded  Popular Question
Jun
27
awarded  Autobiographer
Jun
13
awarded  Supporter
Jun
13
awarded  Scholar
Jun
13
accepted Is it reasonably safe to use PIN code for encryption?
Jun
13
awarded  Nice Question
Apr
25
awarded  Announcer
Feb
24
comment Is it reasonably safe to use PIN code for encryption?
But I wouldn't even need to construct a rainbowtable since storing (or calculating) 10,000 hashes is not that hard on my memory (processor).
Feb
24
comment Is it reasonably safe to use PIN code for encryption?
A rainbow is a smart way of storing encrypted passwords yes. And if a salt is used it would probably need to be specially constructed just for cracking passwords with that salt. This is not a very hard operation when there are only 10,000 passwords to choose from. Note that the Salt is always considered known to the attacker (since it seems to be read from /dev/urandom in the docs this is most likley stored either in clear text or encrypted with the user password). Either way the the user password is the weak link.
Feb
21
awarded  Editor
Feb
21
revised Is it reasonably safe to use PIN code for encryption?
Many answers missed the point of my question, so edited for clarity.
Feb
21
comment Is it reasonably safe to use PIN code for encryption?
Yes, but I feel like it would be a simple solution to the problem to have different passwords for unlocking screen and for decrypting the device (as I mentioned here android.stackexchange.com/questions/17086/…) since they are used in different senarios and need to have different attributes.
Feb
21
comment Is it reasonably safe to use PIN code for encryption?
Thank you for this nice comment! One thing though; am I not looking for the user password (which most probably will be a 4 digit pin, because you are forced to share key with screen unlock and anything else will be a hassle to type in to make a phone call) to decrypt the 128 bit AES key? (instead of searching for the key directly). If I hash all 10000 pins with the PBKDF2 function + salt, isn't there just 10000 decryption attempts for me to try then?
Feb
19
comment Is it reasonably safe to use PIN code for encryption?
Yes, against login attempt on the unlock screen, but not against decrypting the harddrive. That is what I am trying to say, the screen unlock doesn't need to be as long as the harddrive encryption (which needs to be much longer than 4 numbers) and thus one shouldn't be forced to use the same for both.
Dec
18
comment Is it reasonably safe to use PIN code for encryption?
Well, I am looking for an answer to whether there is some reasoning behind this. If anyone one knows a way around this. If not, where is a good place to turn to drop a feature request. The google android team or Samsung (running clean install of Android 4.0.1)?