# All Questions

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8 views

### How do you solve Textbook RSA? I'm given ct, n, and e

I'm doing a CTF challenge and I'm trying to solve textbook RSA. Could someone answer this question teaching me how? Thanks Challenge: e = 3 n = ...
17 views

### Online AES Calculator

I am currently looking into how AES works and found a calculator online: http://testprotect.com/appendix/AEScalc I understand that the AES process has 10 rounds of calculations. Does this mean that ...
11 views

### how does wireguard encrypted verifies with public key

After stumbling upon this question, I wondered if I could obtain a behaviour similar to WireGuard (private and public keys) by using the same WireGuard private key to encrypt a message via OpenSSL in ...
43 views

### How to minimize Aes Output size?

I work on a project about CAN bus and i want to encrypt the data among nodes but i have have a problem because CAN bus nodes receive and send 8 bytes among each others and I know the size of Aes ...
29 views

### Is OpenSSL enc using AES-256-CBC to encrypt large files safe?

I first generate a keyfile with openssl rand -hex 64 -out keyfile. I then encrypt the file with ...
15 views

### In sha256, is it possible to use less information than the full preimage to prove that the prefix of the preimage is a certain string

Alice split a long string P into two segments A and B. A is relatively short and B is long. H = sha256(A + B) Bob does not know P, but knows H. Is it possible for ...
13 views

### How to find out the cyphering method of 2 cyphered keys with their respective 2 resulting deciphered keys? [closed]

I have 2 ciphered keys and the 2 resulting deciphered keys. Is there any way I can use this information to find out the cyphering method and use it to decipher another key? ...
66 views

### Using zk-snarks to verify a highest bid

I understand that we can verify that given a private input a and a public input b that we can verify ...
30 views

### Does my SHA-256 TableSalt algo give away the seed salt?

The Setup I have a table of values for which I need to compute a salted hash for each table-cell value. Furthermore, I need the salt for each table cell to be unique and unpredictable. (I can explain ...
8 views

### Decrypt encryptedKey session key using - AES-128 - PKCS-1#rsaes-kem-kdf2-kw-aes128

I have basic knowledge about how encryption algorithms work such as RSA, AES and so on. I have an XML response encrypted with both AES and RSA. I tried using OpenSSL to decrypt with several steps but ...
45 views

### It possible to encrypt .bmp bitmap files using Stream Cipher Chacha20?

Maybe this sounds like a stupid question. I'm sorry for that. I just wanted to know is it possible to encrypt a bitmap image file like *.BMP, and generate the ciphertext which is an obscure bitmap ...
22 views

40 views

### In crc32 table look-up method, the polynomial is 0x104c11db7, why does the first two digits of the hash table not collide?

Python crc32 table lookup method, https://github.com/221294583/crc32 .I can understand that the generated table does not collide. After all, as long as the start and end of the polynomial binary are 1,...
624 views

### What does existential unforgeability mean in a digital signature scheme?

In a digital signature scheme (Gen, Sign, Verfiy) that satisfies correctness and existential unforgeability, can you assume that the outputs of Sign() are computationally indistinguishable from random?...
54 views

### Adding liquidity to my token pool [closed]

Ive made a token coin on the bnb netwrok. im a little stuck on the liquidity pool side of things. I have a few thousand to put in but dont understand it completly, So if I put the money in the pool ...
85 views

### What are the algebraic normal forms for each bit of $z$, where $z = (x \oplus y) \oplus ((x \wedge y) \ll 1)$ (a non-linear operation in NORX)?

Let $x, y, z$ denote three $n$-bit words such that $$z = (x \oplus y) \oplus ((x \land y) \ll 1).$$ The NORX paper contains the generalized description of the algebraic normal forms for each bit of $x$...
19 views

### Simple question about BGV scheme

While I'm trying to implement BGV scheme myself, I found that I'm really confusing about the encryption and decryption of the scheme. Here's my understanding: Let $p$ be a plaintext modulus and $q$ be ...
59 views

### Why is factorial used in Pollard's $p - 1$ algorithm?

Why exactly do we use factorial for finding an $L$ which is divisible by $p - 1$? Pollard's algorithm is about B-powersmooth numbers & not B-smooth numbers. So where exactly does the factorial ...
22 views

### How are the points computed in the ElGamal elliptic curve encryption algorithm?

I was looking at an example of the ElGamal encryption operation here (page 24), but I can't seem to understand why: $$\beta = 3(10, 3) = (10, 8)$$
34 views

### Zero-knowledge proof of committed value

I am considering the following questions and would appreciate any help. Problem formulation: Suppose Alice holds a secret value $x$ and there is a public Boolean predicate function $\texttt{Pred}$ ...
27 views

### Coin tosses in the context of commitment schemes

I was reading the “Fast Multiparty Threshold ECDSA with Fast Trustless Setup” paper by Gennaro & Goldfeder, 2018 and I encountered this portion (Sect. 2.4, p.6): This excerpt leaves me slightly ...
12 views

### Can Merkle signatures be leveraged for key exchange?

A Merkle signature scheme is post-quantum-suitable as it relies only on the security of a one-way function. However, this construction seems to only be capable of authentication, and not ...
2k views

### How did law enforcement decrypt messages of ANOM devices?

Wikipedia: The ANOM sting operation was a collaboration by law enforcement agencies from several countries, running between 2018 and 2021, that intercepted millions of messages sent through the ...
62 views

### is it efficient if blockchain uses double Hash algorithms $H_1$ and $H_2$?

I wonder is it efficient to use less Target condition and double hash algorithms with different target (or the same target with different Hash algorithms) and one nonce in a Block. Example Target 1 ...
26 views

### Verifiable Delay Function Fast Computation

For unknown group order such as RSA groups, it takes $T$ sequential steps to compute the below function (time-lock puzzle). $$y = g^{2^T} mod N$$ This paper states that if $|N|$ (Group order) is ...
28 views

### Differential cryptanalysis to ciphertext-only attacks on xxTEA

In my IOT project, I use the xxTEA encryption algorithm to encrypt my data. I use the same encryption key for all my packets because I don't have the possibility to do a key exchange between Alice and ...
23 views

### Under which conditions certificate is required for IKEv2?

In IKEv2 document, there are expressions as [CERT,] or [CERTREQ,] in the parts of IKE_SA_INIT or IKE_AUTH exchanges. In this notation brackets indicates that it is optional. I didn't see expressions ...
24 views

### Homomorphic encryption key switching

I understand the general idea of key switching, but I would like to know when it is used. Sometimes it is referred to as same thing as relinearisation(after multiplication), but is key switching also ...
26 views

### Is the polynomial system representation of a symmetric cipher overdetermined?

Is the representation of the polynomial system of a symmetric cipher overdetermined?
28 views

### What kind of encryption is this? [closed]

Hey can someone please tell me what kind of encryption this is? This is not the whole encrypted code but you should still be able to tell what it is from the structure. ...
206 views

### VDF / RSA groups

I believe I am overthinking it; however, I need to clear out my doubts. What is exactly RSA groups and how their order is unknown? I know in RSA N is computed by multiplying two prime numbers (p and ...
20 views

### Existential unforgabilty of a separately signed message

Assuming I have a valid signature scheme, and modify it like: m = m0 || m1, and output Sign(sk, m0) || Sign(sk, m1). While it is correct, would this violate existential unforgability?
50 views

### Private key encryption that is not CPA secure

I've been learning about different types of encryption schemes in class and I was wondering if it's possible to create a private-key encryption scheme that is multi-message secure but is NOT CPA-...
14 views

### LR Oracle for CPA Security for Multiple Encryption

How does LR Oracle model help achieve the CPA security for Multiple Encryption. I am not able to understand how LR oracle model gives an advantage over the normal encryption oracle.(Reference to ...
43 views

### Remote Attestation: when to use Checksum and when to use a Cryptographic Hash function?

In computer security applications, to check the integrity of a specific data/program binary, a cryptographic hash function is normally deployed to generate a digest and compare it with a reference ...
28 views

### How to know the exact result in Paillier chiper-costant multiplication

The encryption function $E_{k^+}: Z_n \rightarrow Z_{n^2}$. The decryption function $D_{k^-}: Z_{n^2} \rightarrow Z_n$. $m_1 = 42, k = 15, n=77$. After encryption, exponentiation and decryption, I get:...
I have searched everywhere in academic papers about time complexity of a brute force attack on a Shamir's Secret Sharing key. I'm confused between if it is $O(p^k)$ or $O(p)$, such that $p$ is the ...
An elliptical curve over $GF(2^3)$ is defined as $y^2+xy=x^3+ax^2+b$ with the given value of $a= g^3$ and $b=1$. $R = P + Q$, where $P = (0, 1)$ and $Q = (g^2, 1)$ Can someone solve this question ...