Security and Cryptography
 
Forums: » Register « |  User CP |  Games |  Calendar |  Members |  FAQs |  Sitemap |  Support | 
User Name:
Password:
Remember me

The Shed is going Social! Join us on FaceBook and Twitter and chime in on the conversation.

Go Back   Dev Shed ForumsSystem AdministrationSecurity and Cryptography

Reply
Add This Thread To:
  Del.icio.us   Digg   Google   Spurl   Blink   Furl   Simpy   Y! MyWeb 
Thread Tools Search this Thread Rate Thread Display Modes
 
Unread Dev Shed Forums Sponsor:
  #1  
Old July 23rd, 2012, 06:27 AM
ctopmep ctopmep is offline
Registered User
Dev Shed Newbie (0 - 499 posts)
 
Join Date: Jul 2012
Posts: 3 ctopmep User rank is Just a Lowly Private (1 - 20 Reputation Level) 
Time spent in forums: 48 m 4 sec
Reputation Power: 0
Crypto Protocol Question - Determine encryption protocol

Is it possible to determine encryption protocol in use having result of the encryption?
I am evaluating an application and I am not very satisfied how it handles confidential data. It is using another program for encrypting, which takes string as input and it's output is encrypted file. I tried to find encrypted text on the web that looks similar to it's output, but without success. Below is hexdump output of encrypted sting "123"

0000000 c476 d382 0ddf a246 71af 7055 ba5a dfb4
0000010

Reply With Quote
  #2  
Old July 23rd, 2012, 06:52 PM
requinix's Avatar
requinix requinix is online now
Still alive
Click here for more information.
 
Join Date: Mar 2007
Location: Washington, USA
Posts: 12,717 requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)requinix User rank is General 120th Grade (Above 100000 Reputation Level)  Folding Points: 417516 Folding Title: Super Ultimate Folder - Level 1Folding Points: 417516 Folding Title: Super Ultimate Folder - Level 1Folding Points: 417516 Folding Title: Super Ultimate Folder - Level 1Folding Points: 417516 Folding Title: Super Ultimate Folder - Level 1Folding Points: 417516 Folding Title: Super Ultimate Folder - Level 1Folding Points: 417516 Folding Title: Super Ultimate Folder - Level 1
Time spent in forums: 5 Months 1 Week 4 Days 7 h 29 m 55 sec
Reputation Power: 8969
Send a message via AIM to requinix Send a message via MSN to requinix Send a message via Yahoo to requinix Send a message via Google Talk to requinix
So a block size of 128 bits, okay, and it's not a (unsalted) MD5 hash of "123"...

What application? Is the output always 128 bits long?

Reply With Quote
  #3  
Old July 24th, 2012, 01:42 AM
ctopmep ctopmep is offline
Registered User
Dev Shed Newbie (0 - 499 posts)
 
Join Date: Jul 2012
Posts: 3 ctopmep User rank is Just a Lowly Private (1 - 20 Reputation Level) 
Time spent in forums: 48 m 4 sec
Reputation Power: 0
The application is using external program for encrypting database connection string.
The program that is used for encryption takes two strings. First one is connection string and second is encryption key. Output of this program are two encrypted files. I guess that first one contains encrypted connection string, and second one contains encrypted encryption key. Any copy of the application can decrypt this files. I guess that decryption key for this files is hard-coded in the application.
I am concerned about security of this approach because if I am right, both encrypted data and encryption key are available to the potential attacker and they are encrypted with hard-coded key.
The data in the application is not very confidential, but I am willing to refuse it if I find it insecure to save me from future headaches.
Below are hexdumps for both encrypted data string and encrypted encryption key.

Source for both of them is "qwertyuiop1234567890"

Data:

0000000 a19c 5555 de82 c198 a682 1501 93c5 9ed8
0000010 eeda 1709 a7f6 aced
0000018

Key:

0000000 854e 90a8 0a26 d2ce 3eaf f0d6 1ac1 80f1
0000010

Reply With Quote
  #4  
Old July 26th, 2012, 08:14 AM
OmegaZero OmegaZero is offline
Contributing User
Dev Shed Novice (500 - 999 posts)
 
Join Date: May 2007
Posts: 737 OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level)OmegaZero User rank is General (90000 - 100000 Reputation Level) 
Time spent in forums: 3 Weeks 5 Days 1 m 12 sec
Reputation Power: 928
If you need to evaluate the security of someone's application, they should at least provide you with a specification if not access to the source code itself. Just by looking at the output you can at best guess at the underlying algorithm (e.g. 8N data lengths point toward an 8-byte block cipher like DES), but you can't tell if the algorithm is being used properly (e.g. what mode is the cipher used in? Is a secure padding method used? What is the source of the IV and key material?)
__________________
sub{*{$::{$_}}{CODE}==$_[0]&& print for(%:: )}->(\&Meh);

Reply With Quote
  #5  
Old July 30th, 2012, 01:45 AM
ctopmep ctopmep is offline
Registered User
Dev Shed Newbie (0 - 499 posts)
 
Join Date: Jul 2012
Posts: 3 ctopmep User rank is Just a Lowly Private (1 - 20 Reputation Level) 
Time spent in forums: 48 m 4 sec
Reputation Power: 0
I don't have access to the source code.
Since the encryption key is hard-coded in the application, I thought I can try to encode some string and try brute force on it to test if it is easily breakable.
The problem is that I don't know which algorithm is used for encryption, so I can't choose tool for testing it.
I guess that if the algorithm is not easily recognizable, the application is not that much insecure as I thought.

Reply With Quote
Reply

Viewing: Dev Shed ForumsSystem AdministrationSecurity and Cryptography > Crypto Protocol Question - Determine encryption protocol

Developer Shed Advertisers and Affiliates



Thread Tools  Search this Thread 
Search this Thread:

Advanced Search
Display Modes  Rate This Thread 
Rate This Thread:


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
View Your Warnings | New Posts | Latest News | Latest Threads | Shoutbox
Forum Jump

Forums: » Register « |  User CP |  Games |  Calendar |  Members |  FAQs |  Sitemap |  Support | 
  
 


Powered by: vBulletin Version 3.0.5
Copyright ©2000 - 2013, Jelsoft Enterprises Ltd.

© 2003-2013 by Developer Shed. All rights reserved. DS Cluster - Follow our Sitemap