# decoding

1. ### Decoding Matrix

Hi, I am stuck on reducing the following matrix. It is supposed to be in H = CI format where C = Coding matrix and I = Identity matrix 1 1 1 1 1 1 2 3 4 0 and its a mod 5 matrix I am wondering if anyone could help me reduce the above matrix to following format using row operations * * * 1 0...
2. ### Decoding

Hi all, I hope my post is in the right section. I need some help with decoding a Playfair code. I only have the ciphertext which is 22 lines long. What's the best way to do this? I red that I have to do some frequency analysis of the English bigrams which I did. There's one combination which...

Recently I've got a homework of Decoding Theory. But I can barely understand what my professor means about this assignment. Is it something about finite fields? Can somebody explain it for me? And how do I write a program on GAP? (I have never used it before.) :Write a GAP program and compute...

Recently I've got a homework of Decoding Theory. But I can barely understand what my professor means about this assignment. Is it something about finite fields? Can somebody explain what it means for me? :Write a GAP program and compute the following: Take p = 2, 3, 5 Take a primitive element...
5. ### matrix message decoding

How do I set this up and how do I do the calculations? The message: 39 57 7 10 11 11 36 44 5 5 33 48 14 19 19 19 was encoded with matrix A. A =| 1 2 | .....| 1 3 | | 1 2 | 39 57 7 10 11 11 36 44 | 1 3 | 5 5 33 14 19 19 19 19 or | 1 2 | 39 7 11 36 5 33 14 19 | 1 3 | 57 10 11...
6. ### Pseudo random counter decoding

Hello, I have a pseudo random counter that looks like below. Briefly what it does is to generate a "random" number every time the system is clocked. I say "random" and not random because the register values in the counter follows the same pattern every time, if you start from 0. If the...
7. ### Coset Decoding

I know that to find cosets I have to add something to the word Y but not sure what or how to decode. I think You add vectors with all 0 entries and one entry of 1? How do you know which one is the coset leader? thanks in advance.
8. ### Decoding a message

I could use all of the help I can get with this...it did not make any sense to me when my teacher explained it. Ok so here's the problem Let p=13 and q=23. Let e=5. Decode the message: When I think about my professor, I think about 69,214,69. 1. First find d with de congruent to 1...
9. ### Decoding letters

Can anybody shed some light on this as how to solve it with equations: T W O X T W O ------------- T H R E E
10. ### needs help in decoding this ideal 4PAM TxRx code in Matlab

I am new in Matlab and following a book to develop a software radio. i can't understand why i am not getting the right decoding -answer. i just added code for block code to the already given code. I will appreciate your help thanks in advance.
11. ### Logical problem about encoding and decoding letters with numbers.......

First let me say Thanks for viewing....... This is type of question which will have some logic, using which any word can be coded......I tried a lot but couldnt crack it...... CAn anyone pls help me out...... If CANE is coded as 1345 and MEAN is coded as 8453, what is TOKENS coded as? (A)...
12. ### Theoretical Neuroscience - Neural Decoding

Hi All, I was wondering if anyone on this forum knows anything about Neural Decoding. I am having a little trouble with this section of my course. Basically I have a set of Poisson spike trains with 5 different stimuli and different average firing rates. I need to calculate numerous...
13. ### encoding and decoding help

I have the following.... p=311 q=173 m= 53803 Euler Totient = 53320 k=3 message is the string of digits 232 524 141 135 192 911 331 529 252 315 a1= 232 a2= 524........a10=315 In the form a^k = = b (mod 53803) I don't know how to find b....I have been going in circles for the past 4 hours and...
14. ### decoding

In a cryptosystem we use the ordinary alphabet numbered 0 to 25. We number digraphs using enumeration to base 26. We encode digraphs using the affine transformation f(x) = 213x + 111(mod 676) What is the decoding transformation? Let y = 213x + 111(mod 676) Then y = 213x = y - 111(mod...
15. ### Decoding bits set

I'm looking for a fast routine for decoding bits set in a UInt64 (C#) The one I'm using now is (I have an array called BitMasks[65] with BitMasks[0] = 0) static ushort DecodeBits(UInt64 BitMask, ushort[] arrValues) { ushort Index = 0; ushort...