# Questions tagged [cryptanalysis]

Analysis of individual security aspects of a cipher or algorithm, not the security of a cipher or algorithm in general (which would lean towards “algorithm-design”).

1,496 questions
Filter by
Sorted by
Tagged with
53 views

• 35
154 views

### How much information do I leak if I upload multiple ciphertexts with cleartext overlaps?

Suppose that $t_1, t_2, \ldots, t_n$ are my clear texts. Suppose that for any $(i,j) \in \{1,2,\ldots,n\}^2$, $t_i$ and $t_j$ only differ in, say, the 1st $m$-many characters. Finally, suppose that I ...
• 553
335 views

### are outputs of sha256 independent when padded with different seed each time, in other words, when inputs can be somewhat related

So I was wondering about what will be the dependence of the outputs when I padded one input with two different strings two times for technically generating two different strings, say the input string ...
1 vote
180 views

### Examples of multi output bit balanced Boolean functions

I am trying to find out and learn more about Balanced boolean functions. Wikipedia states that " a balanced boolean function is a boolean function whose output yields as many 0s as 1s over its ...
• 111
161 views

### Is the one-time pad secure if the key is computed so the ciphertext will consist only of "A"?

I recently learned about the one-time pad method, which has perfect security if the following conditions are met : The key must be truly random. The key must be at least as long as the plaintext. The ...
• 176
233 views

### Understanding Linear Cryptanalysis

I'm reading about the linear cryptanalysis of an SPN and I have some questions about the practicality of this. The example I'm looking at is from 3.3.3 of Stinson's Book and I believe the same example ...
• 141
51 views

### RSA PADDING WITH e=3 [duplicate]

I have a ciphertext which has been padded with spaces from left the message is 31 bytes long and e = 3 how can I recover the message with python code .
1 vote
1k views

### Frequency Analysis on DES, AES, 3DES using Cryptool2

I am trying to analyze symmetric block ciphers like DES, 3DES and AES, using Cryptool 2. I want to do a frequency analysis on each of these ciphers, in order to comment whether this is an effective ...
• 113
554 views

### Is AES without T-Tables nor S-Box resistant to side-channel?

T-Tables and S-Boxes are prone to side-channel attacks, is an implementation without any lookup tables resistant to side-channel ? In this answer, https://crypto.stackexchange.com/a/63520/80926, the ...
110 views

### Are there issues in how cryptography is used in this short code sample?

I want to encrypt some small text files so I can put them online, in non-restricted access (not the best idea, but it's cheap and simple). I know I should use something like Truecrypt instead of this, ...
• 703
1 vote
464 views

### Is AES S-Box resistant to side-channel attacks?

I know that implemntations with T-tables such as Golang's are prone to side-channel attacks, but is AES's S-Box wihtout any additional table also insecure ?
1 vote
127 views

### Can someone help me understand this?

In the book Serious Cryptography It says for a cipher's permutation to be secure "Different keys should result in different permutations. Otherwise it becomes easier to decrypt without the key: ...
34 views

• 31
120 views

### Anonymous key exchange protocol not secure vs. computationally unbounded adversary

Explain why an anonymous key exchange protocol cannot be secure against a computationally unbounded adversary.
145 views

### What is the difference between different corona tracing protocols?

At https://corona-tracing.org/ and https://www.cryptool.org/en/cto-highlights/corona-tracing an easy to understand way was presented how such contact tracing apps work from a cryptographical point ...
• 51
181 views

### Cryptosystems defined over the real numbers

In a computational setting it is clear that we cannot do computation over the real numbers, as we couldn't generate, much less store them, so we have to instead deal with numbers that approximate them....
• 514
281 views

### Attacks on LCG with "self-XOR" output function?

Consider an ordinary LCG modulo $2^n$ with an internal state of $n$ bits and an output of $n/2$ bits, with the twist that instead of simply truncating the state to produce an output, we take the upper ...
• 7,418
80 views

### would this be classed as a cipher text attack?

Say i'm given a cipher text to decrypt, however i also have access to a server that performed the encryption; where i could enter any plaintext and observe the result of encryption. would it be ...
219 views

### Hash function without avalanche effect but with few collisions

I am searching for a hash function which has these attributes: low Avalanche Effect, similiar files should get similiar outputs low number of collisions (if I have 0*10000 in one file, and 0*99999 + ...
• 103
1 vote