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# Questions tagged [transposition-cipher]

A classical cipher in which the ciphertext is obtained by scrambling the letters of the plaintext.

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1 vote
72 views

### Is this transposition cipher unbreakable?

Given a password as a seed for a Psuedo Random number generator and Fisher Yates Algorithm to shuffle bytes of a string to random places like Hello World to ...
• 19
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### What is the post-quantum security of encryptions schemes based on transpositions?

I know that if using Grover's algorithm to break a cipher, one would need to perform (2^[key space])^0.5 queries (the square root of the number of all possible keys). A simple transposition cipher ...
• 393
639 views

### What is a block transposition cipher?

I was looking at the archives for the British national cipher challenge, and a modified version of an ADFGVX cipher came up twice (2003 2011), with block transposition instead of columnar ...
609 views

### What's the difference between permutation and transposition?

I am trying to understand the difference between permutation and transposition. I have seen a similar question in the forum but I would like to ask you for proper definitions and examples of each. I'm ...
1 vote
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### How can I determine the number of times I have to reapply the Scytale until the original plaintext comes back?

Given "①②③④⑤⑥⑦⑧⑨⑩⑪⑫" as plain text and a 4 rows Scytale inscription with 3 as the length of the longest row, the original plaintext is back after 5 runs: ①④⑦⑩②⑤⑧⑪③⑥⑨⑫ ①⑩⑧⑥④②⑪⑨⑦⑤③⑫ ①⑥⑪⑤⑩④⑨③⑧②⑦...
2k views

### How to determine which type of transposition cipher I have?

I have some ciphertext that I have determined using frequency analysis to be most likely encrypted using a transposition cipher, as the letter frequencies are similar to plain English language text. I ...
113 views

### Tranposition Ciphers

I am studying classical ciphers and have the following doubts: Is the row and columnar transposition cipher the same? It is similar since the process of encryption and decryption is the same for ...
1 vote
81 views

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### Transposition cipher - brute-force-attack - expected value

how do I calculate the expected value of a brute-force-attack on a transposition cipher? For example, for the text "HELLO", there are 5! = 120 possibilities. Is the expected value to break the ...
86 views

### How to evaluate the security of transposition ciphers?

how to evaluate the security of transposition ciphers? I am specifically interested in the security of turning grilles and how to (mathematically) evaluate their security. I would appreciate any help....
656 views

### How to break an unknown ciphertext - transposition of some kind [closed]

I've been challenged to crack a code. All I know about it is that is was hand-enciphered, and that it is a transposition cipher of some kind. When I was given it, I started plugging it into my ...
• 474
2k views

### How to distinguish a transposition cipher from a simple substitution cipher only given a ciphertext?

I am working on one interesting question. There is a ciphertext that has 10,000 letters. We need to distingish whether this ciphertext was encrypted by a transposition cipher or a simple subsitution ...
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### Can a message be encrypted with BOTH mono-alpha and poly-alpha ciphers?

For my class assignment, I was given this text; Qpuvu vo vv stazpuykzh Hhycmlmv asb. Ad dhyaqva wh uyo uzb jpwww Avlw. Tkpjllfdmbp zoatz vzjavfvna ZLHqh. Amva luy yyvlz yu bhk zua zlhvvalaz yow ...
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### Are some combinations of Substitution + Transposition more vulnerable than others?

Iterating multiple substitution ciphers is not mathematically different from using a single substitution cipher (3 Vigenere iterations with a 31-, a 32-, and a 33-letter key would essentially be a ...
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1 vote
738 views

### what method of transposition does AES 256 encryption use

I'm interested in learning how to use AES-256 encryption in C/C++. I'm still a beginner in Cryptography but I'm confident in my abilities to program. There is still a lot for me to learn about this ...
227 views

### can a key be applied to half the cipher text

id like to ask if we encrypt the word "hello" as "olleh" but then we apply the key to only "oll" will it be converted into its orginal form i.e "llo". this was just for example. another thing id like ...
26k views

### How to solve Columnar Transposition Cipher without a key

I have been given a 77 character message for decryption, but no matter where I look all the Columnar Transposition scripts out there are all requiring of a key. I believe the number of columns to be 7,...
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1 vote
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### Acceptable condition for dictionary search

I am trying to write a program to break transposition cipher using dictionary search. But I cannot understand the finishing condition of the search. Is there any theory that the maximum number of ...
280 views

### How to glean info from a message that simply has the letters shuffled?

Suppose someone had published a several hundred page (sensitive) book, but had randomized all of the letters in an order known only to them (e.g. with a vector of random numbers of the same length as ...
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1 vote
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### How to calculate how many trials I need to guess the plain text if a simple P-Box is used to make the cipher text

If I have 64 bit as input for a straight box that use a transposition process to encipher the plain text and the given 64 bits contains 60 bits as (1s), then how many trial I should do?
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### Are transposition ciphers insecure?

Given plaintext: P[i], i = 1..N Given stream of cryptographic numbers S[i, j], i = 1..N, S[i, j] in [1, j] generated by RC5 for example We encrypt using Fisher-Yates shuffle algorithm: ...
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1 vote
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### How to encrypt and decrypt a transposition cipher?

I encrypted the text hello there with a 3x4 table with the key 2 1 3. I fill in the text into the table row by row and got the ...
1 vote
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### Getting inverse of a transposition key

I'm new to security stuff and I have some questions about the keys of transposition cryptography. If I'm given the encoding key to a transposition cipher, how do I get the decoding key for it? I ...
5k views

### How to break a columnar transposition cipher?

I'm currently studying for a cryptography exam. I've been given ciphertext that has been encrypted by a columnar transposition cipher. I've been given no shift key length or key word, the only thing I ...
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### Improve security of transposition ciphers

As we know, breaking a Transposition Cipher is quite trivial and can be easily done by either exploiting single letter frequencies (not $d$-gram frequencies though, given that $2 < d < L$), or ...
1k views

### Recovering key length from transposition block cipher ciphertext

First of all I would like to say hello to all StackExchange users. So far I've been stalking the forum for some time, now it's time to leave the shadows. In my master thesis I'm writing about ...
214 views

### Is this transposition cipher information-theoretically secure for 1 message?

Given: $m = \{0,1\}^{n}$; a plaintext message of length $n$ encoded in binary $k = randomshuffle([0, 1, ..., 2n-1])$; A secret key consisting out of unique numbers between 0 and $2n-1$ in a true ...
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### How secure is bit level permutation?

Could anyone explain how secure is bit level permutation? What is the most serious threat against the security of this kind of cipher?
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### Shannon confusion and diffusion concept

I read the document(not the whole document) from Shannon where he speaks about the concepts of confusion and diffusion. I read in many places(not in the document but around the internet) that ...
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### How to solve cipher encrypted with Vigenère + Columnar Transposition?

Vigenère's weakness is Kasiski's test and index of coincidence. However, if you put columnar transposition on top of Vigenère, that weakness is gone. The text is now shuffled and you can't search for ...
7k views

### Frequency analysis of transposition ciphers

Can we do frequency analysis of transposition ciphers? If yes, please tell me the procedure and I would be happy if you provide me with some links related to it. I heard that it can be done using bi-...
1 vote
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### What are requirements for this grille?

I'm trying to program a Cardan grille, but I can't find requirements for grille. In my case, grille is square matrix A with $N$ x $N$ size, and elements are $0$ or $1$ (where $1$ means that it is hole)...
1k views

### What is total key space in transposition algorithms

How we can measure key space in transposition algorithms? Should we specify the method, like rail fence?
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