# All Questions

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### In RFC 2313 (PKCS1/RSA) said you could recreate the Private key from 'n' and 'd', which later versions removed. Why?

RFC 2313 has this specific callout: ...
• 101
34 views

### Impossibility of uniform generation in random world

I was reading Limits on the provable consequences of one way permutations by Impagliazzo and Rudich when I got stuck on a sentence. First of all, they define a polynomial relation that is any relation ...
• 38
28 views

### How to prove that signature hash is wrong without reveal message

Let's say we have Bob, Alice and third party. Bob make message signature hash and upload to third party, then encrypt message with Alice pub key and send it to Alice Alice receive message and decrypt ...
20 views

### How to anonymously poll for information in a small group of people?

A company wants to poll employees about their view of the company (by using a web system, say). They would like to do it anonymously, but they don't want people filling out forms more than once. An ...
• 133
48 views

### Probability when representing message as a point on elliptic curve

There is a very popular method to represent a message m (number) as a point on elliptic curve over a finite field: Set $i = 0$ Check whether $m'=m\cdot K+i$ is on elliptic curve. If not, try again ...
30 views

### How do bad actors manipulate game results in real time within 'provably fair' gaming systems?

Ive been assigned research involving online gaming companies and their use of cryptographic algorithms to produce 'provably fair' results. The largest player in the industry uses a method involving a ...
1 vote
54 views

### Recursive NTT for Kyber

since the NTT is a variant of the DFT respectively FFT, it seems possible to implement a recursive algorithm for the NTT of Kyber with a divide-and-conquer concept. This is the reason for my question ...
1 vote
65 views

### Point doubling for a point on Elliptic Curve (15,13) + (15,13) = (2,)

Consider the elliptic curve E1:y2=x3+7 over F17 with the base point G=(15,13) I am trying to compute point double of (15,13) i.e (15,13)+ (15,13) Expected point is (2,10) , however I am not able to ...
93 views

### Possible to encrypt message without knowing recipient public key?

Assume Bob is sender and Alice is future recipient. In ideal situation Bob know Alice public key, and encrypt message with it. But what if Bob don't know Alice public key (he only will know Alice ...
64 views

### Factoring RSA $N = pq$ knowing that $(p+q) >> 200$ [closed]

We have $N = pq$, with $p$ and $q$ are prime numbers, and $hint = (p + q) >> 200$. How to find $p$ and $q$?
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### Kerberos authentication only works with aes256-cts-hmac-sha1-96 for Windows 10 [closed]

I have a Windows 10 server joined to a RedHat IDM realm using Kerberos. When a user tries to authenticate on a Windows 10 server, the following error is shown On the IDM, looking at the ...
• 101
1 vote
45 views

### Input/Output size of compression functions

I know that DES has 56 independent key bits, and that 3DES has 168 independent key bits by using 3 seperate 56-bit DES keys. 3DES also has a block size of 64 bits. If I use 3DES as the underlying ...
• 11
59 views

### Cryptanalytic attacks ASCON MAC

I am researching ASCON. I can find cryptanalytic attacks ASCON authenticated encryption and ASCON HASH, But I am not finding anything ASCON MAC. Anyone knows of any attacks, any research on this?
36 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
38 views

### hybird proof on q-query pke classic scheme

I am reading the proof of the advantage of q-query kem attack should not be much greater than 1-query kem attack without loss of generality(for example, one time pad is secure but two time pad is ...
1 vote
58 views

### Extended-Chacha20

Research paper: "Extended-Chacha20 Stream Cipher With Enhanced Quarter Round Function" The initial matrix is 6x6, but what are the exact inputs for each index, in other words, how will you ...
• 21
1 vote
22 views

### Argon2 confusion when computing J_1 and J_2

I'm implementing Argon2id from the RFC 9106 and I'm at the part where each thread computes J_1 and J_2 in order to generate indices [l] and [z]. I'm confused as to which TYPE (y = 0, 1 or 2) of Argon2 ...
1 vote
30 views

### Efficient decoding a code dual to a Goppa code?

Consider a matrix $H \in GF(2)^{a \times b}$ where $b > a$. This defines two linear codes. First, we have the code for which $H$ is the parity check matrix:  C = \{ \mathbf{x} \in GF(2)^b | H \...
• 111
39 views

### Unable to encrypt and decrypt using the Generalized-Feistel Cipher from Black & Rogaway paper

I am trying to implement the algorithm suggested in Section 5 of the Black & Rogaway paper titled "Ciphers with Arbitrary Finite Domains" in C++. It is a Feistel cipher that tries to ...
• 1
74 views

### CBC KEY recovery when KEY=IV

We have access to an encryption and decryption server with the following implementation. How can we get the secret key by interacting with this server? ...
69 views

### Using the MAC to verify if Cipher Only attack has succeeded

I am working on an experiment to compare the efficiency of brute-force attacking block ciphers like AES and DES with reduced key sizes for different programming languages and library implementations. ...
• 21
31 views

### I'm wondering if using the same one public key does not guarantee privacy in the computation of multiple data owners

Participating entity: multiple data owners, computing clouds Protocol: The multiple data owners send their data to the computing clouds, which perform the computation of the data. Privacy protection:...
• 161
40 views

### Why the full r-torsion group contains r^2 many elements and consists of r+1 subgroups

let F be a finite field, E(F) an elliptic curve of order n, ...
• 101
1 vote
42 views

### Near Maximum Distance Separable Code

I want to find the minimum distance of an $[8,4]$ Near MDS code over a finite field F_4 (NMDS Code is a type of linear code). I want to know which programming language has a built-in function that ...
110 views

### Additive Secret Sharing of Floating point numbers

Consider a floating point number $f$ in IEEE 754 format with sign, exponent and significand values as $f.s$, $f.e$, and $f.sig$. Given this floating point number $f$, I want to compute the shares of \$...
49 views

### Are high-dimensional versions of NTRU cryptosystem more secure?

The basis for this question is a 1-dimensional NTRU cryptosystem. After some literature inspection I have found out it can be also generalised into higher algebras: quaternions (QTRU) and octonions (...
• 219
92 views

### Performing Point Division on secp256k1 Elliptic Curve for odd Integers

I'm exploring elliptic curve cryptography, specifically on the secp256k1 curve. I've come across the concept of point division by integers using scale multiplication, my question is how can I devide a ...
42 views

### Ed25519 and sealed boxes libsodium

Accidentally used ed25519 public key to create libsoidum_sealed_box. Is there any way to decrypt the data if the private key ed25519 is known?
89 views

### Is it possible to deduce the input of a hash by running in reverse? [duplicate]

If i understand correctly, hashes run a defined set of operations iteratively until the original data is all hashed. Can you take a hash value, run it backward through the last step (or once, for an ...