Introduction

If you haven´t read the original paper about Chaffing and Winnowing yet, I suggest that you do it now.

In this paper, I define a package as the triple consisting of the Serial number, the Message and the MAC.

Let´s design a implementation of the Chaffing and Winnowing system. We assume to use it as a realtime communication link between two hosts over the Internet. For example, Alice wants to transmit the data from the original paper to Bob:

Hi Bob Meet me at 7PM Love-Alice

I added the last package to have more packages with the same serial number:

Package	Grain	Serial	Message	MAC
1		1	Hi Larry	523105
2	*	1	Hi Bob	465231
3	*	2	Meet me at	782290
4		2	I'll call you at	793122
5		3	6PM	891231
6	*	3	7PM	344287
7		4	Yours-Susan	553419
8	*	4	Love-Alice	312265
9		4	Love-Philipp	823949

This would lead to the idea to implement the decoding for the receiver the following way:

1. Read an incoming package .
2. Calculate the MAC, if it is ok, then add the message to the plaintext.
3. Do the upper loop with the next package, until all packages were processed.