Linked Questions

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1answer
775 views

many time pad attack [duplicate]

I am a beginner in cryptography. I studied many time pad attack and now I want to solve a popular exercise, It consists 11 ciphertexts (s1,s2,...,s11), that encrypted by a same key and I want to find ...
1
vote
1answer
498 views

One-time pad encryption of ASCII characters [duplicate]

I can't understand a question I came across in a course. You observe three ciphertexts all resulting from encryption of ASCII plaintexts containing English letters and spaces only, using the ...
70
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3answers
68k views

How does one attack a two-time pad (i.e. one time pad with key reuse)?

My question might appear the same as the question Taking advantage of one-time pad key reuse?, but actually I did read all the answers and none of them helped me with the details I need. I am new to ...
1
vote
1answer
11k views

Many time pad attack (XOR) [duplicate]

The question is quite similar to Many time pad attack and I was trying to rely on the top answer, but still am a bit confused, so any explanation and help will be much appreciated. Assume I have a ...
0
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3answers
4k views

Security of very simple XOR with random? [duplicate]

I am currently trying to implement a very fast and simple encryption algorithm in Lua for the purpose of using it with ComputerCraft. The main problem is that bitwise operations in Lua (5.2 at least) ...
3
votes
1answer
6k views

Cryptanalysis of XOR cipher with repeated key phrase

My assignment is to cryptanalyze cipher text that we know was encrypted with a stream cipher (bitwise XOR of plain text and key stream), and decrypt to plain text. We know the key stream is a repeated ...
1
vote
1answer
4k views

decryption many time pad [duplicate]

I have eleven ciphertexts that were encrypted with the same key (which I don't know). I want to decrypt the last ciphertext. I read similar question like Many time pad attack but I can't solve my ...
1
vote
1answer
727 views

What does it mean when two encrypted files, encrypted with the same method but with different keys, when xor'd together, produce a repeating pattern?

Let's say I have fileA and fileB, both encrypted somehow, but in the same method with different keys. If I xor them together, they will make a repeating pattern of 32 bytes length. What does that say ...
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3answers
296 views

What are the vulnerabilities of this OTP-like system?

I've read that a OTP is only perfectly secure if the key is perfectly random, and the pad is never reused. If you encrypt documents using two keys, where one is random but stays constant for some ...
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2answers
506 views

Little problem with Vernam Cipher

We have got a task with the following content: Given is a language with 3 letters: A, B, C. The binary expression is: A = 000, B = 1111 and C = 0011 Two ...
2
votes
1answer
444 views

Is it easier to crack the Vernam Cipher with more than two ciphertexts

I have just started looking into the cracking of the Vernam cipher with two ciphertexts encrypted with the same key by XORing them and then crib dragging and I was wondering if it is made easier if ...
1
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1answer
403 views

Analyzing/Breaking a strange One-Time-Pad

In my assignment there is a bonus question: It asks me to decrypt a file which has been encrypted using an One-Time-Pad. But the ciphertext seems to contain english word fragments and other parts ...
2
votes
1answer
90 views

Attacks on one-time pad, given a property of keys

An adversary $A$, eavesdrops $n$ cipher-texts, $c_{1}, c_{2} ..., c{_n}$. It also knows a value $v$ and a function $f$ such that $$f(k_{1}, k_{2}, ..., k_{n}) = v$$ where, $k_{i}$ is used to encrypt $...