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ECOM 6031 – Project Part 1
Lab demonstration
I. Mobile‐Aided Encrypted Web File System
. e usage o ruecryp
Junbin Fang
(CYC321, 28578440, [email protected]
)
1
I. Mobile‐Aided Encr ted Web File
System
Encrypte i es are store on We
Keys stored in server, sent via SMS
When PC is connected to a Mobile
from Web after getting a key from
If PC is disconnected from the Mobile
Files cannot be decrypted on Client‐Side
Demo is available
2
Architecture
Ke distribution server
erver s e 1
Check key request in an
Verify the phone number
in the SMS
Send an encrypted key
back through SMS
3
Architecture
File server
erver s e
Authenticate any login
.
Retrieve the key sent to
user from key distribution
server.
Encrypt files with the key
us ng , etc.
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Architecture
User’s mobile phone
ent s e 1
Run an app to send a key
Parse the response SMS
from key distribution
server
Decrypt the key encrypted
y ey server w t ts
private key such as IMEI
5
Architecture
User’s PC
ent s e
Communicate with his
secret key for decryption
Decrypt the files
encrypted by file server.
Display
the
content
in
a
ava app et rame
6
ey s r u on
Key management and preparation
1 ,
2 , …
File encryption keys: K AES1 , K AES2 , … (related to F 1 , F 2 , …)
Encr ted files: C = Enc F K C = Enc F K …
One‐time key (session key): K OT (it is generated and
used for each session)
Encrypted keys: CK 1=Enc(K OT ,K AES1 ), CK 2=Enc(K OT ,K AES2 ),…
IMEI‐dependent number: K OT XOR IMEI = NIMEI (which
w e ransm e v a an . or s mp c y,
computation is used here.
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ser exper ence
Step 1:
User “Paul” logins to the File Server by using username and
,
.
Cisc.txt and hku.txt.
Since the files are encrypted, after login, a Java Applet will
be run to check the presence of K OT (UI as window W1).
If K OT is given, the applet can go on to do the decryption. If
not, a warning message wi e s own.
F1 ‐ Cisc.txt W1
Error during key retrieving
2 ‐ u. x
8Get secret key K OT ?
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ser exper ence
tep :
If K OT is not given, the applet can not decrypt the file
w c e user wan o open.
Then the user need to run an App in the client‐side
receive N IMEI from Key Distribution Server via an SMS.
Actuall user need to re uest N before he want to
read some files.
9
ser exper ence
tep :
If N IMEI is received successfully, the App will parse it , . , , .,
extract the session key K OT.
If the applet can get a correct K from mobile
phone, the user can click on any file listed to see the
content. (eg., K OT is used to compute K AES2, K AES2 is
.
F1
‐ Cisc.txt W1F2 ‐ Hku.txt
Key retrieved successfully:
****************
2 ‐ u. x e n vers y o ongKong is the territory'soldest university …
10Get secret key K OT ? W2
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sage o ruecryp
About Truecrypt
‐
Creates a virtual encrypted disk within a file and
moun s as a rea s .
Encrypts an entire partition or storage device
Preparation
Download www.truecr t.or downloads Tutorial www.truecrypt.org/docs/?s=tutorial
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sage o ruecryp con
Our demo’s operations Create a secure virtual
volume
Set password and keyfile
Mount dismount a
secure file as a disk’s
artition *store encrypted
*store keyfile in an
volume in
Harddisk
um
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rea e a secure v r ua vo ume
First, create a “truecrypt” file in an
ex erna : c
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e passwor an ey e
Previous keyfile – “02.jpg”
Now – “tc110208 kf” _
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oun a secure vo ume
Password is
required
Keyfile is also
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uccess u y moun ng
An 1 Gb volume
has been
successfully
mounted
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Before mounting
After mountin
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O en file in the encr ted
volume
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ey es
Keyfile
is
a
file
whose
content
is
combined
with
a
password
with password.
Until the correct ke file is rovided, no volume that uses
the keyfile can be mounted.
Any kind of file (for example, .txt, .exe, mp3**, .avi) can be
used as a TrueCrypt keyfile (however, we recommend that
you prefer compressed files, such as .mp3, .jpg, .zip, etc).
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an om ey e genera or
22
Q A
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