# Questions tagged [hill-cipher]

The Hill cipher is a historic polygraphic substitution cipher invented by Lester S. Hill in 1929.

45 questions
Filter by
Sorted by
Tagged with
29 views

### Help With Weird Hill Cipher On Phone After Network Intrusion [closed]

Hackers Left a Hill Cipher on My Phone. I found the cipher below after experiencing a network intrusion. Decode.fr identifies it as a hill cipher. It was typed out on my phone when I was not looking. ...
1 vote
42 views

### How to uncover keys from using double encryption schemes such as Hill and Vernam Cipher

I have a quick question. How would you decrypt an encryption scheme, involving both Hill and Vernam Cipher. The order of encryption is Hill Cipher then Vernam Cipher. Problem is that only final cipher ...
1 vote
408 views

### Calculate the key of a Hill-cipher using known plain- and ciphertext

I know I should calculate the multiple inverse of plaintext with ciphertext $\pmod {26}$. However, the problem I have is that the plaintext is a $3 \times 4$ matrix which is not square, so how would I ...
1 vote
97 views

### Z superscript confusion

I was practicing some questions on cryptography (newbie) and came across this question: I know that Z26 means modulo-n arithmetic is used, but what does the superscript (3) denote? My guess is that ...
• 13
30 views

### What are some statisitcal characteristics of a hill cipher?

Given a ciphertext, after performing a frequency analysis on it, how would you identify it as a hill cipher? What should i expect to see in the statistics?
1 vote
998 views

### Hill cipher concepts

I have some questions about the Hill cipher. There is a rule for key K: Determinant of matrix and number of characters of the alphabet must be coprime. What does ...
• 111
1k views

### Impossible hill cipher question

I've been trying to solve this question from Forouzan's book ("Cryptography And Network Security") and haven't been able to wrap my head around how to solve it. The plaintext “letusmeetnow” ...
67 views

### Where can I find standardized implementations of lightweight cryptographic ciphers?

I am working on a project that requires encrypting messages with different ciphers. I am looking for the following ciphers: PRESENT, CLEFIA, LEA, Hill cipher, Affine cipher, Elliptic Curve ...
663 views

### Are there ready-to-use software that can try many decryption techniques on a ciphertext, with no information?

Let's say I receive a 1 MB encrypted file, but I get no information about the encryption method, and no password. The only thing I can guess is that the person probably used a weak encryption method ...
• 543
875 views

### Block cipher linearity (in relation to hill ciphers)

So while I knew hill ciphers were a form of block cipher (I'm assuming all the ones I have solved to date were ECB or something similar), so that got me thinking. Is it possible to use hill ciphers in ...
• 65
1 vote
537 views

### Hill Cipher Plaintext Attack: Dealing with Non-uniqueness of Matrix Inverses?

I'm following along with my book. Here is an example of a plaintext attack from it: It is known that: plaintext = 'friday' ciphertext= 'pqcfku' $m$ = 2 We will use this to form the following matrix ...
• 135
316 views

### Hill Cipher how to encrypt and decrypt when both "I" and "J" are in plaintext

In Hill Cipher, let's assume the key is "KEYWORD" and I want to encrypt "JUICE", so after encryption, I get "GXLBWU", and when decrypt ciphertext I get back "IUICEX" not "JUICE". So my questions are: ...
1 vote
763 views

### Hill Cipher with unequal matrix

How can we encrypt a text in Hill Cipher with a key matrix that is 3x3 when the plaintext is even like "ATTACKS"? Do we need to add padding like "x" or "z" to make the matrix equal? Thanks.
4k views

### Hill cipher: How to find an unknown key of unknown size

How would you tackle the problem of finding the key (you don't know the length) to a Hill cipher when knowing only one 12-letter word of plaintext and its corresponding ciphertext? CONVERSATION has ...
1k views

### Hill cipher -- obtain matrix key [closed]

I have to solve Hill's cipher. I have only cipher text: CGQIYN and key: CFDG. I don't know how to decrypt it, because in all ...
987 views

### Hill Cipher if the length of the string is not divisible by the Key Dimensions

For a project, I want to encode the word "MEMBRANOPHONES" with the key "MULTITONE". I try spliting "MEMBRANOPHONES" into groups of 3, but then I get "MEM", "BRA", "NOP", "HON", leaving me with a 2 ...
• 101
618 views

### How can I determine the Hill cipher key in this case?

I have been struggling with a Hill cipher problem for many days, without any luck. I have the following ciphertext, which I know is an encrypted excerpt from an Edgar Allan Poe story: ...
• 121
838 views

682 views

### Can Hill Cipher be considered as Asymmetric?

I know hill cipher is a block chipher ,We produce decryption key by inverse of key matirx but we still use different key for decryption. Therefore Can we say that Hill cipher is asymmetric chipher?
• 85
1 vote
162 views

1 vote
608 views

### Hill Cipher the point of a known plaintext attack question

Is the point of a known plaintext attack on a Hill Cipher to get the matrix key?
• 23
1 vote
2k views

### How to encrypt letters less than block n using Hill Cipher

I am learning about Hill Cipher and know that it is a block cipher where each block of n letters (considered as an $n$-component vector) is multiplied by an invertible $n \times n$ matrix, again ...
• 179
1 vote
4k views

### how to find key matrix in hill cipher

I want to solve this problem but there are 3 known plaintext-ciphertext pairs. The key of Hill cipher is a 3*3 matrix as k=[k1,k2,3; k4,k5,k6; k7,k8,k9] where the unknown ki={0,1,...25}={A,B,......
• 111
553 views

### Hill Cipher question

Recently, I was given three ciphers to crack for my cryptography class. At this point, I have guessed that one of them is likely a Hill cipher (probably 3x3, as that is the most complex we have done ...
976 views

### Security of the iterated Hill Cipher

I can understand that the basic Hill Cipher is susceptible to known plaintext attacks, but suppose the Hill Cipher is modified into the Iterated Hill Cipher. For a plaintext $x_0=m_0$ and an ...
1 vote
1k views

### How can I decode a Hill Cipher without a key? [duplicate]

On my exam, we had to solve this problem: message matrix is: [20, 19, 14; 17, 0 10] and the ciphertext matrix is: ...
1 vote
6k views

### Hill cipher key space

Key space is the set of all possible keys that can be used to generate a key. We using the number of valid key to describe it. I've given a hill cipher of block size $k$ over alphabet of size $p$, ...
• 157
8k views

### Hill cipher cryptanalysis - known plaintext known key size

Hello I want to know how to go about this problem I know the plaintext "abcdef" and the ciphertext. The key size is 2. I really can't figure out how to find the key for decrypting and encrypting.
2k views

• 33