0
votes
0answers
79 views

What is the non-programmable random oracle model?

I would like to know the difference between the random oracle model and the non-programmable random oracle model. ​ What is the difference?
4
votes
1answer
90 views

Finding all polynomials up to a given degree to generate a bit sequence

Consider the following bit sequence: 00100000110 Using Berlekamp-Massey algorithm we can find the following minimal degree polynomial: $P(x)=x^6 + x^5 + x^4 + 1$ Now, is there a way to find all ...
0
votes
0answers
18 views

Notation of * in hash function of identity-based encryption

$H:\{0,1\}^{*} \rightarrow Z_{p}^{*}$ $H:\{0,1\}^{*} \rightarrow Z_{p}$ $H:\{0,1\}^{*} \rightarrow G_{1}^{*}$ $H:\{0,1\}^{*} \rightarrow G_{1}$ Difference meaning of $Z_{p}^{*}, Z_{p},G_{1}^{...
9
votes
1answer
109 views

Is it possible to test implementation for side-channel attacks?

When it comes to implementing cryptographic algorithms, there seems to be a big focus on the difficulty of doing so without introducing the potential for side channel attacks and the knowledge ...
1
vote
3answers
149 views

Any benefit to writing a message as a mix of 2 languages before encryption?

For example, imagine a message that is a mix of Japanese and English words; Japanese in unicode, English in ASCII. Japanese doesn't use spaces between words. The sentence structures, anything ...
0
votes
0answers
44 views

Found weil pairing. Index Calculus method on the results of weil pairing

Consider Elliptic curve with p = 59, A = 1, B= 0, P = (25,30) and Q=(35,31). So I tried to solve this using MOV attack. The torsion point for them E[5] is R(-25,30i) where is sqroot -1 Chosen two ...
3
votes
1answer
68 views

Parameterizing adversaries with security parameters

In many cryptographic games, the adversary doesn't seem to be parameterized by the security parameter.‡ Are such games equivalent to variants in which the adversary is parameterized by the security ...
11
votes
2answers
974 views

Can any MAC be used as a KDF?

First, let me clarify what I mean with a Key Derivation Function (KDF). I'm interested in KDFs that take an $n$-bit symmetric master key and some diversification data of arbitrary length as input and ...
3
votes
2answers
108 views

Importance of round complexity in determining the efficiency of an MPC protocol

Literature has different ways of specifying complexity of an MPC protocol: computation complexity that measures the number of (assumed primitive) operations performed by all the parties; ...
0
votes
0answers
35 views

Dependency of cryptographic protocols on cryptography primitives

To what extent depend cryptographic protocols on cryptographic primitives? Are there cryptographic protocols that can only be implemented with certain cryptographic primitives? If the answer is yes, ...
0
votes
0answers
55 views

Why is RSA still being used? [duplicate]

In hybrid encrytion, I still see that some site's use RSA in their https connection, so now I wonder, why do they not use ECC instead of RSA, ECC requires less computational power and encrypt's and ...
3
votes
0answers
47 views

How to decrypt the below encrypted messages? [closed]

My friend was experimenting with the encryption methods (self-made) to encrypt text using ASCII map. He wanted to try this idea whether this encryption can be broken and so shared an encrypted text ...
2
votes
1answer
541 views

Decrypting a blowfish cipher with three keys

Disclaimer: I'm pretty new to cryptography and I don't have a strong mathematical background. I apologize in advance if I missed something blatantly obvious. I participated in a security CTF this ...
2
votes
3answers
67 views

Is there a method/protocol to validate a self-signed certificate by comparing a shortened hash?

I'm working on a solution where an iPad should connect to a server software running on a laptop using TLS with a self-signed certificate that was automatically generated on the laptop during the ...
0
votes
1answer
64 views

Given a prime exponent e and a prime number n, find b, where b^e = 1 mod n

Can anyone help me with the following problem. Given a prime exponent $e$ and a prime number $n$, find $b$, where $b^e \equiv 1 \bmod n \land b > 1$. For example, $b^5 \equiv 1 \bmod 11$ how to ...
-2
votes
1answer
56 views

In Shamir's (t, n) secret sharing scheme why don't use infinite field? [duplicate]

Well, we use finite fields to select shares. What happened if we use infinite fields.then will the scheme be vulnerable? Easy to break? Or share generation and reconstruction will be difficult? ...
1
vote
1answer
36 views

Given C is a code of length n. Containing M code-words with a distance d

I'm studying for my exam and came across this question below. I don't understand how to get $d$. I get $C$ is a code of length $n$. Containing $M$ code-words with a distance $d$. $(n,M,d)$ But how ...
2
votes
1answer
136 views

How does DH work when combined with ECC or RSA?

I know that Diffie-Hellman is used to create keys in a secure way over an insecure channel. But there is one thing which I cannot understand: I see that a lot of sites use ECC or RSA alongside DH. ...
5
votes
1answer
55 views

Binary format of encrypted PGP private key?

Short Version of the Question: I would like to remove any predictable information from an encrypted private keys binary representation. Does anyone have a hint where the binary format for encrypted ...
3
votes
1answer
140 views

Is the use of AES in LoRaWAN correct?

I'm reading about LoRaWAN (specification). This network protocol has a particular way to encrypt data, detailed in the part 4.3.3.1. Here is a recap of how the encryption work, as I understood it. ...
2
votes
1answer
49 views

Find an example of a lattice such that LLL algorithm can't find the shortest vector of the lattice, satisfying

I want to find an example of a basis of a lattice of dimension $n$ such that LLL algorithm can't find the shortest vector of the lattice, and such that the shortest vector of this lattice, say $b=...
0
votes
0answers
27 views

Password manager that uses a mix of long and short key derivation functions

I was reading "A Convenient Method for Securely Managing Passwords, Halderman et al., 2005". In short, the authors say to do the following: ...
5
votes
0answers
47 views

Quantum complexity of LWE

As per my understanding LWE is quantum secure because there is no known quantum algorithm to solve LWE in polynomial time. Due to the reductions given by Regev et al. If there is any algorithm that ...
2
votes
0answers
60 views

Are analog quantum computers a threat to RSA and DLP?

We already know that D-WAVE's "quantum computers" can't really run the Shor's algorithm, because the way they're built doesn't qualify them as universal quantum computers. Now researchers actually ...
3
votes
1answer
95 views

Salting Hash stored on RFID tag?

In my application, I am trying to prevent counterfeit widgets from being used on our gadgets; think HP ink-cartridges. I will be doing such with UHF RFID tags embedded in the widgets. Unfortunately, ...
0
votes
0answers
71 views

Security Proof in Fuzzy Identity Based Encryption?

Been having a great deal of difficulty understanding the use of simulators to prove security of ABE schemes so I though I would start from the first ABE paper (Fuzzy Identity Based Encryption) to try ...
1
vote
1answer
48 views

Conditional probability with Vigenere Cipher given specific plaintexts and key sizes

Apologies if this should be in the Mathematics stack exchange, I just ask it here because the context is cryptography. Here is the question that I seemingly cannot get correct: Consider the ...
3
votes
1answer
61 views

Conditions for Perfect Secrecy with the Vigenere Cipher

Please forgive my ignorance here as I'm far from a math major and I've never looked into cryptography before so if this seems stupid - it probably is. There is a question in a quiz I'm attempting that ...
0
votes
1answer
65 views

Questions about length key of RSA 2048 bit

I use putty gen to generate RSA key, I choose length of key is 2048 bit, it generate public key: ...
3
votes
1answer
76 views

proof of correctness Ring-LWE cryptosystem

I've been studying Ring-LWE based crytposystems such as the one in this paper, but I can't seem to find/come up with a proof of correctness for this particular scheme. The encryption goes as follows: ...
2
votes
1answer
122 views

Forgery attack against Textbook RSA with simple redundancy

I know how to forge vanilla Textbook RSA message signatures (easy). I've learnt that by adding a good redundancy to the message, it cannot be forged anymore. How can one add redundancy so that the ...
0
votes
0answers
24 views

Diffie-Hellman combined with DSA/RSA

we have learned Diffie-Hellman, RSA and DSA (Digital Signature Algorithm) in university. Because DH is vulnerable of Man-in-the-Middle we had the task to program the DH combined with RSA to protect ...
1
vote
1answer
29 views

Can I use the Sequence Number as the (implicit) IV in AES-GCM IPsec?

The RFC https://tools.ietf.org/html/rfc4106#page-5 states that, under AES-GCM IPsec, each packet is expanded by 8 bytes for the IV and up to 16 bytes for the ICV. Why? Since we already have a ...
3
votes
1answer
79 views

tripartite diffie hellman with Weil pairing

I try to understand how the tripartite Diffie-Hellman key exchange works. I read Joux's paper for this: https://www.semanticscholar.org/paper/A-One-Round-Protocol-for-Tripartite-Diffie-Hellman-Joux/...
5
votes
1answer
73 views

What is the most efficient attack on NTRU?

So, I got how finding the private key is equivalent to resolving the SVP. I also understood that the LLL algorithm can only be used in small dimensions. Now, I wonder what is the most efficient attack ...
3
votes
1answer
123 views

Change initial hash value of SHA512/t

Fips 180-4 defines under 5.3.6 how to calculate initial hash values for SHA512/t for a given value t. Can someone explain me how the t actually affects the outcome of the procedure (which, as far as I ...
5
votes
1answer
671 views

What does this notation stand for when describing a code?

This code has appeared in some online course material. I understand the $(5, 4, 3)$ refers to (length, num codewords, distance) but no explanation of the $Z_2^5$ notation is given: One $(5,4,3)$ ...
0
votes
1answer
33 views

factorization of an integer $N$ that is in special format

Suppose $p_0$ and $q_0$ are known prime numbers and define $p_i$ and $q_i$ as follows: $$p_{i+1} = next\_prime(p_i^2 + q_i^2), \qquad i \ge 0$$ and $$q_{i+1} = next\_prime(2p_iq_i), \qquad i \ge 0$$ ...
1
vote
0answers
33 views

Are public key and private key exchangeable? [duplicate]

If I get a key pair from RSA algorithm, can I make Private-Key public, and keep Public-Key secret without breaking the security of encryption and signature?
5
votes
1answer
106 views

Nonce for AES GCM to prevent replay attacks

I am wanting to encrypt a message with a pre shared key that uses AES GCM from the OpenSSL library to do so. I generate my key for the AES crypto via hashing my pre shared key with a salt using the <...
0
votes
0answers
31 views

What is the best approaches to find the type of a Cipher / Encryption? [duplicate]

There are many known and unknown encoding and encryption types / algorithms. When the algorithm is known, then at least it gives some direction or approach on what to do next to obtain the plaintext ...
5
votes
1answer
72 views

Are there any high level memory-hard PBKDF constructions?

The PBKDF2 construction from PKCS #5 v2 has the convenient feature that it can be implemented using only standard interchangeable cryptographic primitives. Specifically, it only requires the ...
0
votes
0answers
28 views

Error Detection/Correction Code-Then-Encrypt

I've just studied about the error correction schemes and encryption. First rule when using EDC/ECC is to first encrypt and then calculate them, and the major motivation we were told is that "EDC/ECC ...
0
votes
1answer
33 views

Secure Cipher Suites supported by JDK versions [closed]

I'm a n00b to cryptography. I've been searching through oracle's java docs, ssl labs, googling and more googling attempting to find an up to date list of cipher suites considered secure for the ...
4
votes
1answer
70 views

What is the recommended number of iterations for Argon2?

I've recompiled my operating system ("LionBSD" based on FreeBSD) to use Argon2i as the default password hashing algorithm in crypt/libcrypt. I'm wondering what the recommended number of iterations ...
0
votes
0answers
15 views

How much bandwidth is used in a typical IKE/ISAKMP initialization?

How much bandwidth is used in a typical IKE/ISAKMP initialization? How many UDP packets are sent in each direction, and what is their typical size? I'm referring to initialization of IPsec via IKE/...
2
votes
1answer
44 views

what kind of custom header add to encrypted file to identify my encryption,consider safe and reliable.like pseudo format extension or file size

I want to add some custom header to encrypted file to identify my encryption,consider safe and reliable.like pseudo format extension or file size.Is there any algorithm or tool to make it?
4
votes
3answers
255 views

After a diffie hellman key exchange, what is the common secret used for?

What is the common secret that is established used for? What types of interactions are now possible?
2
votes
1answer
26 views

Older key as PGP subkey?

Currently I have a 2048-bit PGP key. Suppose I create a new 4096-bit key. Can I add that old key as a subkey of this new one?
3
votes
1answer
53 views

Is a hash function used to expand the key after ECC shared secret is complete?

I am trying not to solicit opinions, but I have not been able to find a reference to the question at hand. I have designed an ECC engine in silicon that handles any curve in the form of $y^2 = [ax^3 +...

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