Important: Use custom search function to get better results from our thousands of pages

Use " " for compulsory search eg:"electronics seminar" , use -" " for filter something eg: "electronics seminar" -"/tag/" (used for exclude results from tag pages)

Thread Rating:
  • 0 Votes - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Using Diffie-Hellman, Ciphers, and Hashes
Post: #1

Using Diffie-Hellman, Ciphers, and Hashes

.pdf  Using Diffie-Hellman.pdf (Size: 561.17 KB / Downloads: 11)

Introduction: Sending Files Securely

A common issue when sending files over email is security. Say you want to email a sensitive file to somebody
else, but you don’t have any previously shared secret or code which will enable you to send it securely. The
tool you will develop for this assignment addresses this issue, allowing you to securely encrypt and send a
file to the other person without having any previously secure communication mechanism.
The fundamental steps in establishing a shared AES key and Initialization Vector (IV) is shown in
Figure 1.

What to do

Your job is to develop an application which will enable Alice and Bart to perform the above steps. To help
you get started, an empty version of the GUI shown below is provided on Moodle.
Let’s consider a sample run of the algorithm where p = 64601, g = 3, Alice chooses her password “Castor”
and Bart chooses his password as “Pollux”.

Testing Your Application

Your tool should be able to encrypt and decrypt both text and binary files. Managing binary files will require
you to use the BinaryWriter and BinaryReader stream management classes in C#. You can read more
about them in the online documentation.
To help you test your application, there are two encrypted files on the course web page. One is a text
file and one is a PDF (binary) file. They have been encrypted with the same keys that Alice and Bart used
in the above example (p = 64601, g = 3, Alice’s secret “Castor”, Bob’s secret “Pollux”). You may use them
to test your decryption routines.
Be sure to test your application with other example primes and primitive roots. Some useful links:
• Lists of prime numbers:
• A list of the first 10,000 prime numbers at:
• A helpful web site with a Java application to derive primitive roots of prime number is found at:

A Note on Modular Exponentiation

You will find that the standard data types in C# are not sufficient to calculate large modular exponents the
simple way (calculating g a and then calculating the modulus with p). You will end up with an overflow in
many cases. A more efficient, bit oriented algorithm exists (you can read about it online), but since we are
dealing with relatively small exponents (16 bits long) we can calculate modular exponents in a reasonable
amount of time recursively. A prepared function in C# to calculate recursive modular exponentiation is
given on the course web page. You may copy it into your application code and use

Quick Reply
Type your reply to this message here.

Image Verification
Image Verification
(case insensitive)
Please enter the text within the image on the left in to the text box below. This process is used to prevent automated posts.

Possibly Related Threads...
Thread: Author Replies: Views: Last Post
  generating electricity using rotating door in ppt Guest 1 262 18-11-2017 11:02 AM
Last Post: jaseela123
Sad hide image inside another image using java source code Guest 1 208 18-11-2017 10:10 AM
Last Post: jaseela123
  interfacing lcd with 8255 using 8086 Guest 1 0 17-11-2017 01:07 PM
Last Post: jaseela123
  washing machine control using microprocessor 8086 Guest 1 0 07-11-2017 09:42 AM
Last Post: jaseela123
  PRE-PAID POWER CONSUPTION USING COIN BOX REPORT seminar flower 1 899 27-10-2017 01:01 PM
Last Post: nagaland 8pm today
  Electronics Letter Box Using IC 555 seminar tips 2 2,823 26-10-2017 02:37 PM
Last Post: jaseela123
  Industrial Conveyor System Using Magnetic Levitation system seminar code 2 251 25-10-2017 12:03 PM
Last Post: jaseela123
  detection of glaucoma using image processing techniques Guest 1 0 25-10-2017 11:53 AM
Last Post: jaseela123
Shocked ambulance rescue system using gps and gsm Guest 1 255 14-10-2017 03:25 PM
Last Post: jaseela123
  case study of bata shoes company using mis Guest 1 265 14-10-2017 01:03 PM
Last Post: jaseela123
This Page May Contain What is Using Diffie-Hellman, Ciphers, and Hashes And Latest Information/News About Using Diffie-Hellman, Ciphers, and Hashes,If Not ...Use Search to get more info about Using Diffie-Hellman, Ciphers, and Hashes Or Ask Here