Is the key of this encryption (transposition cipher) correct?

  • Context: Comp Sci 
  • Thread starter Thread starter shivajikobardan
  • Start date Start date
  • Tags Tags
    Encryption
Click For Summary

Discussion Overview

The discussion revolves around the correctness of a transposition cipher key and its application in encoding plaintext. Participants are examining the columnar arrangement of the ciphertext and the corresponding key digits, with a focus on identifying potential mistakes in the column numbering.

Discussion Character

  • Debate/contested

Main Points Raised

  • Some participants assert that "RSES" is correctly identified as column number 3, not 6, suggesting a mistake in the original claim.
  • Others propose that if the ciphertext is arranged according to the columns in increasing key-digit order, then the encoding appears correct, though they express confusion about the mistake being referenced.
  • One participant provides a detailed column numbering system, indicating their interpretation of the order based on a key of 5263174, which leads to a specific arrangement of the ciphertext.
  • A later reply challenges the encoding procedure based on the textbook's illustration, suggesting that the method of writing out the plaintext and the use of padding may be incorrect.

Areas of Agreement / Disagreement

Participants express differing views on the correctness of the column numbering and the encoding process, indicating that multiple competing perspectives remain unresolved.

Contextual Notes

Limitations include potential misunderstandings of the encoding procedure, the use of padding with 'X', and the dependence on the specific interpretations of the textbook's figure.

shivajikobardan
Messages
637
Reaction score
54
Homework Statement
Transposition Cipher
Relevant Equations
no conversion of Plain Text to cipher, just change the position of plaintext.
1660980188248.png

I don't have much to add in this post as it's apparent from the figure itself.
DAEX
UVFU
RSES is column number 3 not 6. So, I think that's a mistake.

I'm following this book for this sub topic only.

CRYPTOGRAPHY AND NETWORK SECURITY By PRAKASH C. GUPTA
 
Physics news on Phys.org
shivajikobardan said:
Homework Statement:: Transposition Cipher
Relevant Equations:: no conversion of Plain Text to cipher, just change the position of plaintext.

RSES is column number 3 not 6. So, I think that's a mistake.
If the ciphertext is the columns written out in increasing key-digit order then it appears correct to me. Not sure what you mean the mistake should be.
 
Filip Larsen said:
If the ciphertext is the columns written out in increasing key-digit order then it appears correct to me. Not sure what you mean the mistake should be.
uuh it's confusing as there're multiple perspectives.

I first gave columns numbering as it should be, so according to my numbering:
1-GAIO
2-UVFU
3-AETR
4-RSES
5-DAEX
6-LTNX
7-EFHX

And the key here's 5263174
so this'd be the order:
DAEX,UVFU,LTNX,AETR,GAIO,EFHX,RSES
 
Based on the picture from your textbook alone it seems you are doing it wrong. I understand the encoding procedure to be
  1. Write out the clear text one row at a time over 7 columns, padding with X (which seems like a bad idea, but never mind that now).
  2. Write the key so one digit is above each column.
  3. Write out the ciphertext as the full column marked 1, then 2, and so on up to 7.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 13 ·
Replies
13
Views
4K
  • · Replies 3 ·
Replies
3
Views
9K
  • · Replies 1 ·
Replies
1
Views
12K
  • · Replies 17 ·
Replies
17
Views
4K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 2 ·
Replies
2
Views
4K