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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 = ...
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0answers
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 ...
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0answers
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 ...
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2answers
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 ...
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0answers
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 ...
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0answers
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 ...
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0answers
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? ...
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2answers
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 ...
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1answer
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 ...
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0answers
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 ...
2
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1answer
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 ...
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0answers
22 views

How does the public-key generation work in the multivariate post-quantum digital signature GeMMS?

There are a few steps in the public-key generation of GeMSS that I am trying to understand. The first is the below equations (1). What does "$\theta_i$ forms a basis for $\mathbb{F}_{2^n}$ over $\...
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1answer
54 views

Why is this DES key considered weak?

I understand the premise of weak keys in DES and cryptography. From searching online, I understand that keys that are comprised of all zeroes / all ones / alternating ones and zeroes / alternating ...
1
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1answer
10 views

Encrypted verifiable schema with hidden content

I'm having a problem with an encryption scheme. There are two entities, $A$ and $B$. $A$ give a simple message $m \in [0,1]$ to $B$. $B$ should generate an encrypted message of $m$: $e=Enc_{pk}(m)$ ...
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0answers
28 views

Encrypting long messages to the same length keys

I am looking for a simple encryption of the text messages and in order to save some bandwidth, storage etc, I was looking to encrypt them into the same length strings. Something similar to how youtube ...
1
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0answers
19 views

Volume of an NTRU lattice

Let $K$ be a number field of degree $n$ and $\Lambda^q_h=\{(f,g)\in\mathcal{O}_K\text{ : }fh-g = 0\bmod q\mathcal{O}_K\}$, where $h$ is an NTRU public key. Then $\{(1,h),(0,q)\}$ generates a lattice. ...
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1answer
43 views

A few questions about the elliptic curves functionalities

I've been learning about the elliptic curves and how they work, and their usage in cryptography, and I'm trying to figure out how to use them using Go. Where is the 'a' parameter from my ECC equation ...
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2answers
738 views

Can SHA512 and SHA3-512 Make Same Collisions?

Does combining those two different cryptographic hash functions in HMAC, when each hashes the same data separately, then saved together, guarantee zero possibily of a collision simultaneously or is ...
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0answers
51 views

Proof of theoritical security of Shamir's secret sharing

community ! I'm looking for the proof of theoritical security of Shamir's secret sharing. I found some articles saying that it's assimilable to the halting problem, which implies that there is no ...
1
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0answers
22 views

Securing a local database

I am a member of a sports association and I am developping a simple JavaFX application for managing member's license. This application will be used on a notebook without any connection, it has to be ...
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0answers
18 views

Commitment scheme for a possible unordered growing collection of elements

Merkle trees can be used for vector commitment scheme. In particular given two sequences S, S' with the same elements in the same order the merkle root for S will be the same as the one for S'. What ...
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1answer
40 views

AES-GCM can IV be stored alongside in DB?

I'm trying to encrypt and store strings in PHP as per example #1 on the PHP openssl_encrypt documentation. ...
2
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2answers
51 views

Why is a Feistel Network invertible?

As it is depicted above, the Feistel Network uses random function fi which is not required to be invertible. However, if fi is not invertible, how can fi(Li) == fi(Ri-1)? Furthermore, why Feistel ...
2
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1answer
28 views

The error distribution in LWE

$\textbf{Continuous LWE}$ : $(\overrightarrow{a}, b)\in \mathbb{Z}_q^n\times \mathbb{T}$, where $\mathbb{T}=\mathbb{R}/\mathbb{Z}$, $b = \langle \overrightarrow{a},\overrightarrow{s}\rangle/q + e\mod ...
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0answers
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,...
4
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2answers
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?...
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0answers
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 ...
1
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1answer
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 $x$...
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1answer
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 ...
1
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1answer
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 ...
1
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1answer
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: $$\beta = 3(10, 3) = (10, 8)$$
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1answer
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 $\texttt{Pred}$ ...
1
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1answer
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 ...
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0answers
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 ...
9
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2answers
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 ...
1
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1answer
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 ...
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0answers
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 ...
1
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0answers
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 ...
1
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1answer
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 ...
1
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0answers
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 ...
2
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0answers
26 views

Is the polynomial system representation of a symmetric cipher overdetermined?

Is the representation of the polynomial system of a symmetric cipher overdetermined?
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0answers
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. ...
2
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2answers
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 ...
0
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0answers
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?
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0answers
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-...
0
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0answers
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 ...
1
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0answers
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 ...
0
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1answer
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:...
0
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1answer
51 views

Time complexity of a brute force attack on Shamir's Secret Sharing SSS

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 ...
0
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1answer
59 views

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)

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 ...

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