0
votes
1answer
59 views

Using Shor's algorithm to solve the discrete logarithm problem

I have read about Shor's algorithm and my understanding is that it can be used to factor large numbers efficiently. Can Shor's algorithm, though, be used to solve this problem: Find the number $e$ ...
3
votes
1answer
83 views

How can I create pre-determined encrypted results?

I want my encryption results to be the lyrics to Star Spangled Banner. The original text I'm encrypting would be, for instance, the menu to a local pizza place. I know what I want my passphrase to be. ...
7
votes
2answers
384 views

Can Shor's algorithm compromise RSA when both the public and private key are secret?

If RSA is to create a public private key pair and encryption is performed on plain test P to create cipher text C, given P and C could Shor's algorithm be used to find either of the public and private ...
0
votes
0answers
74 views

RSA PlainText without Knowing Private Key

I couldn't solve this problem for three days... In RSA, [n = 13, 19] [e = 3] c1 = m^3 = 83 mod 247 [e=5] c2 = m^5 = 97 mod 247 then, use ...
0
votes
0answers
28 views

correlation between the timing data produced by different keys with similar inputs in AES

Is there or can there be any correlation between the timing data produced by different keys with similar inputs in AES? If yes, what type of correlation?
1
vote
0answers
21 views

How share size is reduced in robust secret sharing?

THIS IS ROBUST SECRET SHARING SCHEME The dealer $\mathcal{D}$ wants to share a secret among the participants $\{P_1, P_2, \ldots, P_n\}$, where at most $t$ participants are malicious and $t<n/2$. ...
0
votes
0answers
71 views

Compute Modulo exponentiation with prime powers

The problem is to find x such that $$x = M^d \mod p^2$$, where M and d are large numbers, and p is a large prime. Ideally we only want to compute $M^d\mod p$ and then use the result to further ...
5
votes
1answer
74 views

Equality checking using additive homomorphic encryption

Given two ciphertexts $c_1 = enc(p_1)$ and $c_2= enc(p_2)$ using any additive homomorphic encryption scheme (or specifically Paillier). Can we find out whether the underlying plaintexts $p_1,p_2$ ...
1
vote
0answers
39 views

Truly Random Values [duplicate]

I am trying to build a one-time pad encryption software and I am thinking about simply using /dev/random to generate keys. My question is: Is it ...
0
votes
1answer
21 views

Hash system to generate same (specified) hash from multiple datasets?

I have a hashed value $X$ and need to ensure that any of the data sets $D_1...D_n$ can be concatenated with a correctional value $C_1...C_n$ and passed into a hashing algorithm to result in the value ...
0
votes
1answer
63 views

How hard is it to generate a simultaneous MD5 and SHA1 collision?

I was recently reading that MD5 is "broken" because it's pretty easy to generate collisions (like 2^(L/2)). And the SHA1 (theoretically) fares no better. The ...
1
vote
0answers
41 views

Countering Cryptographic Attacks

By reading Camellia Design and Analysis document following is my understanding about few cryptographic attacks from designer point of view. Differential and Linear Crypt-analysis. Number of Active ...
4
votes
1answer
48 views

How does the key size in supersingular isogeny schemes relate to their security level?

I'm looking at the De Feo, Jao, and Plût 2014 paper: Towards quantum-resistant cryptosystems from supersingular elliptic curve isogenies. My understanding of section 3.2 Key Exchange, is that Alice'...
1
vote
2answers
55 views

What are KDF parameters in OpenSSL command-line utility for `enc`?

I refer to https://www.openssl.org/docs/manmaster/apps/enc.html and see that the only parameter for key derivation which I can set explicitly (not considering the obvious ...
1
vote
0answers
93 views

How to generate 1000 prime number of 1024-bit with much less time?

I am generating thousand prime number of 1024 bit each. But it takes lots of time. My procedure is as follows. Generate prime number using ...
1
vote
2answers
58 views

AES encryption for pairwise identifiers

I'd like to map a random ID of 16 bytes (sourceID) to another random ID of 16 bytes (targetID). The operation should: only be reversible by me be deterministic There are about 1 million source ...
3
votes
0answers
41 views

How subscriptions are managed in PayTV securely?

Since there are millions of subscriber for each operator in PayTV and each subscriber can subscribe to any of the package or individual channels, how operators transmit Entitlement management messages ...
0
votes
0answers
12 views

Direct Anonymous Attestation

Could anyone explain me Direct Anonymous Attestation in general terms. I have been trying to read the paper but I really cannot seem to get my head around it. It may seem like a dumb question but I am ...
3
votes
1answer
42 views

Concept of “guessed ID” in Authenticated Identity-Based Encryption

In Authenticated Identity-Based Encryption by Ben Lynn, in Proof of Integrity (section 4.3) and Proof of Security (section 4.4), I cannot grab the concept of "guessed ID" . Because encryption differs ...
0
votes
0answers
20 views

Which bytes in an OTA Command Package are encrypted with the KIc by 3DES CBC?

I have an un-ciphered OTA message in clear and I am trying to cipher it so it becomes secure data. The cryptographic checksum is already generated as part of the un-ciphered OTA message. I have the ...
1
vote
0answers
25 views

To utilize asymmetric cryptography in symmetric manner - demand-of-security-definition?

Cryptography can largely be divided into two classes: asymmetric and symmetric. Like homomorphic encryption now greatly restricted in the asymmetric cryptography, the difference of asymmetric and ...
2
votes
1answer
31 views

Last Sbox of a block cipher for Linear Cryptanalysis

I figured I should try to learn about linear cryptanalysis with a super simple cipher with only one Sbox. The problem is that with that approach the last subkey bits seem to be involved in the linear ...
3
votes
0answers
1k views

Cryptography behind the Turing Imitation Key (TIK)

When browsing the internet I found out about this amazing phone. Well, it would be amazing if it was actually obtainable. It's called the Turing Phone, and it is supposed to come with as good as ...
5
votes
0answers
63 views

Increase in AES SBox

AES uses one single Sbox to substitute all 16 bytes in one Round. Will using 16 different Sboxes (with cryptographic properties similar to AES Sbox i.e Non-Linearity of 112, Differential probability ...
0
votes
0answers
32 views

How are the coefficients of the polynomial used in Mix Column stage of AES chosen?

In the book (Cryptography, Theory and Practice by William Stallings), it states: the coefficients of the matrix are based on a linear code with maximal distance between the code words, which ...
3
votes
1answer
60 views

Plotting Running Times of SAT solver

In the the paper "Efficient Methods for Conversion and Solution of Sparse Systems of Low-Degree Multivariate Polynomials over GF(2) via SAT-Solvers" there is a Figure that I can not understand and I ...
0
votes
1answer
60 views

Security when using same salt for different passwords, compared to using different salts?

I have this question I am struggling about: For example, someone suggested improving UNIX authentication by defining 3 different passwords for a user that are stored in the shadow file. All three ...
-1
votes
1answer
55 views

How efficient is OpenSSL? [closed]

It is apparent that OpenSSL is widely deployed and used, but how efficient is OpenSSL? What's some efficiency concerns of it? What kind of methods to they use to make OpenSSL efficient? Do they also ...
1
vote
0answers
86 views

Encrypted comms between devices on LAN

I'm trying to encrypt a protocol that shares data between devices on a local area network (i.e.no connection to the internet). I don't want to use predefined keys because they're too easy to read from ...
-1
votes
1answer
24 views

Which one has better Performance?

Sending secret value in identity-based encryption Using xor : $K \oplus e(g,h)^{\gamma}$ Using symmetric key: Assuming $Key=e(g,h)^{\gamma}$ and encrypt $K$ using $Key$. Which one is better in ...
0
votes
1answer
71 views

What's is the simplest possible example of using cryptography to sign a message?

I am interested in explaining to a total layman the basics of how a network can know that you are authorized without having to compromise your private key. Using an example consisting of simple ...
-3
votes
2answers
65 views

If we know a sha256 hashed value and its message length can we find the message?

Is it possible to find the original message if we know a sha256 hashed value and its message length?
5
votes
1answer
676 views

Encrypting user data with their password?

I had an idea once that all of the user data (including the username) could be encrypted with the user's password. Obviously, most sites would store different data, so using the same password and ...
1
vote
1answer
47 views

Prove that a function is not PRF

Let $G$ $PRG$ and $G'(s)$ equal to the first $n$-bits of $G(s)$, where $|s| = n$. Show that $F_k(x) = G'(k) ⊕ x$ is not a $PRF$. My attempt: Lets assume a $k$ and 2 messages $x_1$ and $x_2$. So, for $...
1
vote
0answers
38 views

Additive homomorphic encryption over small fields

Are there encryption schemes that are additively homomorphic with respect to small fields such as $\mathbb{F}_{2^4}$ or $\mathbb{F}_{2^8}$?
1
vote
1answer
44 views

Is the “Hash Tree” described in this paper the same as a Merkle Hash Tree?

I'm implementing an algorithm from a paper, and part of it calls for using a "hash tree". Since I'd never heard of that data structure I looked it up on Wikipedia. It turns out that the name hash tree ...
4
votes
0answers
41 views

Do we still need HMAC now that SHA3 is here? [duplicate]

In Another look at HMAC from Koblitz and Menezes, they state that HMAC came along because doing h(secret || message) was vulnerable to length extension attacks. But as far as I know, these kind of ...
1
vote
1answer
40 views

Prove that a function is PRF

Let $F : K×K \rightarrow \{0,1\}^{128}$ be $PRF$ function. Is $F'$ $PRF$ ? $ F'(x) = \begin{cases} 0^{128} & \quad \text{if } x = 0\\ F_k(x) & \quad otherwise \end{cases} ...
1
vote
0answers
19 views

How to calculate how many trials I need to guess the plain text if a simple P-Box is used to make the cipher text

If I have 64 bit as input for a straight box that use a transposition process to encipher the plain text and the given 64 bits contains 60 bits as (1s), then how many trial I should do?
3
votes
0answers
61 views

Simultaneous 2 way exchange without trusted third party

Stakeholders: Alice - has a message, M containing a secret, SA that Bob wants, where H(SA) is a hash which may be used by Bob to redeem some Bitcoin time-locked transaction sent previously by Alice. ...
-2
votes
1answer
57 views

Carmichael's function in Cryptography

The Carmichael's function says that for $a\in \mathbb{Z}_n^*$, if $gcd(a,n)=1$, then \begin{equation} a^{\lambda(n)} \equiv 1 \;(mod\; n). \end{equation} My aim is to find $a$ if factorization of $n$ ...
0
votes
1answer
53 views

What is a simple information authentication protocol for constrained devices?

Background: I have an application where devices will poll information from some source on the network. These devices are very basic and have modest processing and memory capabilities. Hashing (and ...
4
votes
0answers
65 views

How to select corresponding ciphertext in anonymous Identity-based broadcast encryption

In identity-based broadcast encryption, suppose the broadcast ciphertext $(r_1,r_2,\dots,r_i,U,W,V)$ is sent to the receiver. It does not describe which user corresponds to which ciphertext part. User ...
0
votes
2answers
66 views

Diffie Hellman Exchange Confusion [closed]

I am working on this question and I am wondering I have figured out the secret key, but my problem is I don't know how to use the secret key to decrypt the ciphertext. Thanks for the help!
-2
votes
1answer
82 views

How many hashes one needs in order to reverse engineer hash function?

If I know the pattern of a hash string, particularly dllldlll or llldllld (d=digit, l=low case letter), is it possible to reverse engineer the hash function? If so, how many hashes ones needs to do so,...
0
votes
0answers
34 views

Security or not in Key distribution

For example, There are 3 clients. I want to deliver specific value $x$ to all clients. $x\leftarrow {0,1,2,...,q-1}$ where q is a large prime number. By using function $f(x)=x*y_{i}*z_{i}$ where i=...
3
votes
1answer
38 views

Is there a way to turn a PGP key into its semi-prime counterpart?

From my understanding of PGP keys they use the RSA algorithms to encrypt/decrypt messages. So, I know that the RSA algorithms use a semi-prime number to encrypt/decrypt messages. So, what I was ...
1
vote
0answers
65 views

Software Security Impossible in Non-Trusted Hardware?

Fundamentally it is impossible to protect software if you can't trust the execution platform (e.g. using a TPM), so what is the point of software security then? With vendors claim that their white-...
0
votes
2answers
2k views

If I can crack the AES, how do I crack the wifi [closed]

I am a student major in math. My teacher said that AES (Advanced Encryption Standard) has many applications. For example, the WPA2 in wifi. Then he taught the theory of the AES and never says how to ...
4
votes
2answers
102 views

Recover elliptic curve order from ECDSA signatures

I need the elliptic curve order to recover the private key from two signed messages with ECDSA. What I have: two signatures signed by the private-key I want to get the messages that have been ...

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