All Questions

-1
votes
0answers
16 views

How do I revoke aws smtp oauth token2 on iPhone [on hold]

How do I revoke oauth 2 tokens and phishing emails
2
votes
1answer
54 views

Attacking AES using Round 1 output

I was reading the paper Differential Scan Attack on AES with X-tolerant and X-masked Test Response Compactor and I have a question in the section Differential Scan Attack on AES. What I understand is ...
0
votes
1answer
28 views

How does MD5 divide the padded message in 16 words?

This is the image from a website that shows all the steps of the MD5 Hashing algorithm: The original message is 'Hello World!'. I don't understand where these values are coming from: For example the ...
1
vote
0answers
25 views

What is the difference between Google's API-Key, OAuth Client ID and AWS Secure Token Service

What is the difference between Google's API-Key, OAuth Client ID and AWS Secure Token Service? Are they are all just providing delegation tokens, except they are from different companies? Is there a ...
0
votes
2answers
44 views

How is EC key encoded in PKCS#8?

I just started working with certificates and signatures. For an application I write I need a key pair for ECDSA signatures, using the elliptic curve secp384r1 (aka NIST P-384). I produced such a key ...
1
vote
1answer
38 views

Getting the s-box input from its output in differential cryptanalysis on DES

If we try to get K4 using differential cryptanalysis on 4-variant DES, how can we get the input of a certain S-box if we know it's output? This seems hard to do since the substitution operation is ...
0
votes
0answers
54 views

Information theoretic secure encryption based on Quantum Key distribution [on hold]

Although it seems like a wildly adopted assumption that composing the One-time pad and QKD is secure, Maurer and Renner showed that this composition is not secure in the general sense. Indeed if the ...
0
votes
1answer
52 views

Type of Encryption Given The Ciphertext [on hold]

I am trying to decode a ciphertext that composes of numbers and letters with a length of 56 bits, where the last three characters are ===. I'm not sure which type ...
0
votes
1answer
42 views

How does AWS Secret key and access key work

Those keys are too short to be public/private RSA keys. What are they? How does it use them to authenticate the client? My guess is: AWS access key ID is a form of unique user/account identifier AWS ...
0
votes
0answers
41 views

How Many matrix inverse of mod 26 [on hold]

I want to know is it possible to calculate How Many matrix inverse of mod 26
6
votes
1answer
81 views

Differential and Linear trail propagation in Noekeon

In the Noekeon Cipher Specification they write the following : The propagation through Lambda is denoted by $(a \rightarrow A)$, also called a step. Because of the linearity of Lambda it is fully ...
0
votes
0answers
31 views

Unbreakable Ciphertext using hill cipher [on hold]

Can anyone help me out by solving this ciphertext using m =2 TUNAISYPLUKUDDDPOOCZZLLCUDVDCYXJEKYIKORRPVAIYPGUUC
1
vote
1answer
62 views

Meaning of the $m$ power of a modular world

A cryptosystem is defined by a 5 tuple $(P,C,K,E,D)$=(plain text, cipher text, key, encryption function, decryption function) So, my question is with the definition given for permutation cipher, ...
0
votes
0answers
50 views

How to decode unidentified encrypted string? [closed]

I have been given a task for decoding this "I5ZGKYLUEBVG6YRAMZUWO5LSNFXGOIDPOV2CAZLOMNXWI2LOM4QSC===" But I am not sure that what type of encryption is this? Can anybody help me out on this?
3
votes
1answer
72 views

Transparent Setup of SNARKs

The STARKs paper states Third, and most important, ZK-PCPs are transparent (or “public randomness” ), which means that the randomness used by the verifier is public; in particular, setting up a ...
2
votes
0answers
32 views

Assumptions underlying the soundness of STARKs

STARKs have recently received quite a lot of attention due to their small proof size and supposedly simple assumptions. The paper introduction itself seems to mainly state that their construction is ...
3
votes
1answer
51 views

How can I exploit the structure of the secp256k1 prime for fast arithmetic?

I'm implementing logic on an FPGA (programmable chip) that does the key verification part of ECDSA on the curve secpk256k1, in which all operations are mod p where $p = 2^{256} - 2^{32} - 2^9 - 2^8 - ...
0
votes
0answers
46 views

Determine the original input to the S-Boxes

The 8 S-boxes of DES were designed to provide resistance against attacks. Small modifications to an S-box can significantly weaken DES. Can the original input (the result of XOR on the expansion ...
1
vote
2answers
53 views

Does an encryption algorithm exist where encrypted data can be decrypted by multiple private keys?

Suppose I have Company1 with their own Public/Private Key Pairs and another Company2 with their public/private key pairs and yet ...
3
votes
1answer
267 views

Is there a symmetric-key algorithm which we can use for creating a signature?

I know that in the asymmetric-key algorithm the RSA signature exists but what about the symmetrical ones?
1
vote
0answers
42 views

How to create an ultra-secure connection between two clients with xor? [closed]

At work, I was asked to create ultra-secure connection over lan between two computers. It will be some kind of messager. I have a bunch of same random data in them(near 100mb). Also I can start a ...
0
votes
1answer
37 views

RSA: Derive modulus from known ciphertexts encoded with same keypairs

I have two ciphertexts $c_1 = m_1^e \bmod n$ $c_2 = m_2^e \bmod n$ I know $c_1, c_2, m_1, m_2$ and $e$. Is there a way to derive n from this? I first thought Franklin Reiter but I'd need an $n$ for ...
4
votes
0answers
68 views

How sensitive is Tiny Encryption Algorithm (TEA) to the magic numbers?

If I needed to implement an encryption algorithm from memory, chances are I would try to implement: TEA https://en.wikipedia.org/wiki/Tiny_Encryption_Algorithm How sensitive is it to the magic ...
-1
votes
0answers
31 views

Can we use Intel sgx for privacy preserving online adexchange? [closed]

Can Intel sgx be used for privacy preservation of bidders along with verification of online auction being carried out by adexchange
-1
votes
0answers
32 views

How to go about decrypting Hexcodes [closed]

I have what I presume is a basic Encryption problem, but do not know how to go about solving it. Are there any resources or tutorials on how to break simple cryptography? I would like to know more but ...
1
vote
1answer
43 views

Which is more secure for hashing: SHA512 or BCrypt with the same salt reused over and over?

Setting aside questions of if BCrypt should even be used in this way, I was just wondering which one would be more secure hypothetically. If you want to know why I don't just use random salts as per ...
1
vote
2answers
156 views

What is a simple 8-bit cryptographic hash function that I can use in a quantum simulation of Grover's algorithm?

I'm taking a quantum computing course in which, for our final project, we must create a proof-of-concept implementation of Grover Search for finding hash collisions up to a difficulty (similar to ...
5
votes
2answers
91 views

What do NM-CPA, and NM-CCA mean?

When I've been researching authenticated encryption, the following terms keep showing up: NM-CPA NM-CCA ....without any definition as to what they mean. I've tried searching the web for their ...
2
votes
1answer
47 views

In the proof that weak OWFs imply strong OWFs, why must the position of $y$ be random?

When proving weak OWFs imply the existence of strong OWFs, the standard construction goes by concatenating several applications of the weak OWF (see, e.g., here). That is, given a weak OWF $f$, the ...
-1
votes
0answers
30 views

Random letter swap soloution

I am working on a way to decipher some text generated by a small piece of code (see below). This piece of code swaps letters in the sentence at random and was wondering if there where any techniques ...
0
votes
0answers
33 views

Vigenere with multiple encryption

I have a school project about cryptography. The question is the following (will only give a short phrase as example, just want to know the method). A text has been encoded with Vigenere 2 times. The ...
7
votes
1answer
988 views

Why is the BSI not using powers of two?

In their Technical Guideline TR-02102-2 Cryptographic Mechanisms: Recommendations and Key Lengths the BSI is giving minimal key lengths for - e.g. the TLS handshake protocol. All of these are not ...
3
votes
3answers
97 views

How to generate a good symmetric secret key

I would like to generate a good secret key, that later will be used to encrypt data symmetrically. I am not sure how to generate a good secret key. I use Linux, I am not sure which sources of ...
3
votes
2answers
106 views

Deterministic Encryption using AES

I am in need of a deterministic encryption algorithm I can use on social security numbers (9 character string, numbers only) that I will store encrypted in a MongoDB and need to be able to search for ...
4
votes
1answer
53 views

Curve25519's Y coordinate of Basepoint origin

The paper High-speed high-security signatures by Bernstein et al. introduces the Edwards curve Ed25519. Concerning the base point $B$, it says that $B$ is the unique point $(x,4/5)∈E$ for which $x$...
1
vote
2answers
57 views

Using Diffie-Hellman secret key to encrypt/decrypt data?

My end goal is to encrypt data with AES-128, send it to other process and decrypt it there. While using DH key exchange protocol. I have used DH to generate a 256 bytes shared secret, but I can't use ...
2
votes
1answer
86 views

Are hashes evenly distributed? [duplicate]

Are all or any hash functions evenly distributed? For example: if you had every combination of 256 bits and ran that through SHA256, would that produce approximately 1 of each combination, or would ...
-1
votes
0answers
34 views

AES encryption what is more secure, more short records or less larger records [closed]

I have a question about AES encryption, but I first have to make some definitions: An entry is a piece of information by the format: {d: str(N>0),p: str(N>7),s: str(N>0)} Where str is a string of N ...
0
votes
0answers
45 views

Why we use S-boxes in DES and Can we not use it? [closed]

your instructor ask us if we do not S-Boxes In DES, Does this make any difference there?
0
votes
0answers
30 views

How can a node establish pairwise shared key with other nodes using its own polynomial share together with other's public values?

A server has a symmetric bivariate polynomial $ F(x, y) = \sum_{{i,j}=0}^{t-1}a_{i,j}x^iy^j$ $\in GF(p)[X, Y] $ of degree $t-1$. For simpliciy, $ F(x, y) = a_{0,0}+a_{1,0} x+a_{0,1}y+ a_{1,1}xy$ mod ...
0
votes
0answers
30 views

Guessing 3DES key from weak keys [closed]

I have CPU access which has a static cipher key in register 0x00. I want to guess the key present in register 00 which is actually a master key used to encrypt/decrypt all other keys. Is there any way ...
0
votes
0answers
42 views

Isogeny of elliptic curve

If we have two elliptic curves $E$ and $E'$ and the points of both elliptic curves are same. Then all the points of $E$ map to all the points of another elliptic curve $E'$. For example $E$ has ...
0
votes
0answers
77 views

Is it possible for an attacker to determine the original input to the S-Boxes in DES?

I am learning about DES, a Feistel 64-bit block cipher with 16 rounds. Is it possible that an intruder can determine the original input to the S-Boxes?
-4
votes
0answers
51 views

Mathematical Cryptography? [closed]

Suppose the ciphertext RSEBA DEUTL ITCUD VSEOS ETRNY AFTYR FETTU TRYAI ICYOB IORHO WUSDI PENYC was encrypted with a keyword columnar transposition cipher and you know that the crib THEPLACETOBE is ...
-3
votes
0answers
39 views

Can you desipher this? [closed]

Suppose you intercept the ciphertext integers [256240668984327106740, 275175761777497610875] and [[179062338465486616526, 829978174228983829922], [101247687231682793041, 366834255982459649046], [...
0
votes
1answer
46 views

What is the significance of $\prod \limits_{i=1}^{t}m_i > p \prod \limits_{i=1}^{t-1}m_{n-i+1}$ in Asmuth–Bloom threshold SSS?

In this paper by Asmuth–Bloom on threshold SSS, the algorithm is as follows: Shares Distribution To distribute $n$ shares of a secret $K$ among the set of participants $P = \{ p_i : 1 ≤ i ≤ n\}$, ...
1
vote
0answers
53 views

Guessing the key in AES256-GCM?

I assume that my case is weird but I've the following information: IV: 0x263e or 0x3e26 Auth tag: 0x25 AES256-GCM encrypted payload: 0x4eec96df534ade4c013a AES256-GCM decrypted payload: ...
0
votes
0answers
25 views

How encrypt with RSA and no padding in dotnet core [closed]

First: yes, I am aware that this approach is not very secure. However, I need to reproduce the encryption results of another project written in swift in a dotnet core API. The long and short of it is ...
0
votes
0answers
38 views

Patarin’s H-Coefficient Technique

I have come across many paper that applies Patarin’s H-Coefficient Technique in various cryptographic securities (KPA, CPA, CCA,...). I am asking kindly if someone could explain it simple with ...
0
votes
0answers
22 views

C# implementations of cryptographic algorithms to test speed of AES [closed]

C# implementations of cryptographic algorithms to test speed of AES I want to test the speed of AES to compere it speed with other algorithms like DES i want c# source code that implementations ...

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