Questions tagged [terminology]

Questions about the meaning and proper use of specific technical terms or notation within cryptography.

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3
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2answers
43 views

What's the meaning of probabilities in differential privacy formula?

I don't understand what does it mean by "The probability is taken is over the coin tosses of K." Does it mean, the probability distribution is generated based on exactly same data but only the ...
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2answers
101 views

What is cryptographic sealing?

While revising my CAdES library I encountered some "sealing issue" in digital signatures. The Win SDK signtool.exe has a /seal ...
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1answer
43 views

Asymmetric Encryption - How is the Public Key Being Shared?

I've been reading up on the relationship between private keys and public keys (as well as hashing), and I watched a few videos, but I am still a bit confused. I don't have a programming background, ...
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1answer
79 views

Difference between hash functions and algorithms?

Wikipedia lists "Hash function algorithms" within the "Hash function" page. I'm wondering what are the differences and if I can use the terms "hash(ing?) algorithm" and "hash function" interchangeably....
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31 views

Term for non-ARX symmetric-key cryptographic primitive design strategy

What's the term for describing designing symmetric-key cryptography primitive out of bitwise operations and shifts and rotations? The closest thing I've found is this Keccek team's page calling it ...
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4answers
296 views

How to use “mod” related words in technical paper?

Modular reduction is a widely used arithmetic operation. I found many "mod" related words such as modulo modulus modular Can anyone explains the difference among these words? Please give examples ...
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1answer
64 views

Why ``adversary'' and ``challenger'' and what are typical roles of those?

I'm confused with words adversary and challenger, that are used in proof of security of some cryptosystems. For example, adversary and challenger appear in the formal definitions of IND-CPA, IND-CCA, ...
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3answers
57 views

“Work factor” and “iteration count” nomenclature in adaptive functions

In adaptive functions like PBKDF2 / bcrypt I often read people refer to "iteration count" and others refer to "work factor", and they seem to be used interchangeably (even though they're not - the ...
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2answers
56 views

What does it mean by 'cost' in CS?

I've seen the word 'cost' being used several times in describing algorithms e.g. algorithm A costs more to compute than algorithm B. What does 'cost' mean in this sense?
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2answers
159 views

Are ephemeral keys symmetric or asymmetric? [closed]

My question is: Are ephemeral keys symmetric or asymmetric? If symmetric, can ephemeral keys be created based on a (UserID || nonce)?
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What is the origin of the phrase “Don't roll your own crypto”?

The phrase is well-known and widely used, it is often attributed to Bruce Schneier and is indeed relevant to his Schneier's Law. However, I wasn't able to find this specific wording among Schneier's ...
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1answer
57 views

Are multi move proof protocols still “sigma protocols”?

Conventionally, sigma protocols are defined as being a three-move protocol (1. commit, 2. challenge, 3. response). Reading papers like "Bulletproofs" (Bunz, Bootle, Boneh et al., 2018), it feels like ...
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1answer
106 views

Mutual Index of Coincidence

I can't seem to find a simple explanation of Mutual Index of Coincidence. I am finding explanations of Mutual Index of Coincidence not Index of Coincidence. I don't understand what the formula below ...
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1answer
895 views

Difference between decryption and deciphering?

Is there a technical difference between decryption and deciphering?
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2answers
284 views

Does classifying an integer as a discrete log require it be part of a multiplicative group?

This question is not a question about the discrete log problem, the generalized discrete log problem, or an additive group. The confusion is whether any integer can be considered a discrete log or ...
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3answers
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Why was the term “discrete” used in discrete logarithm?

Is there anything especially "discrete" about a discrete logarithm? This is not a question of what is a discrete logarithm or why the discrete logarithm problem is an "intractable problem" given ...
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2answers
156 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 ...
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1answer
70 views

How should one refer to the smallest remainders generated by a modulus within DH or DLP?

It's my understanding that the integer base and exponents chosen to create the initial public keys in DH are from the remainders of a modulus. For example, if the value of the modulus is $N=11$, a ...
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2answers
736 views

What is meaning of the term “language”?

I don't have much formal background, and I could not find a suitable explanation for this after searching on Google/Wikipedia. What is the meaning of the term "language" as used in cryptographic ...
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2answers
405 views

Does GCM (or GHASH) only provide 64-bit security against forgeries?

In a recent comment a doubt was voiced about my answer, which claims GCM to requires $2^{128}$ for a successful forgery. The doubt was that the square root needs to be taken meaning the security would ...
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1answer
77 views

The meaning of formal and semi-formal in cryptography

The question is about "formal" analysis, proofs, etc... What is a correct definition of a formal proof, or a formal analysis? Is there a good way and a bad way to formally prove something. What is the ...
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3answers
99 views

Terminology: Is a block cipher in counter mode still considered a block cipher or is it classified as a stream cipher?

I'm confused about what terminology to use. I see people referring to such a cipher-MOO combination using both terms.
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0answers
78 views

What is meant by the term “hostile environment”? [closed]

I come across many time a term called ”hostile environment” in cryptographic literature. What does “hostile” mean exactly? Is it unknown third parties which are responsible for handling and routing ...
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2answers
246 views

What does the term “nontrivial rotation” mean?

The paper “Gimli: a cross-platform permutation” contains the following information: Occasionally (after rounds 24, 20, 16, etc.) Gimli adds an asymmetric constant to entry 0 of the first row. ...
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What is the difference between TRNG and CSPRNG?

I understand the output of a TRNG is almost impossible to reproduce, such a flipping a coin 100 times to produce a 100-bit sequence. However, it is also my understanding that a CSPRNG produces an ...
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1answer
864 views

What does “seed” mean in cryptography?

I have come across "seed" many times, and at each time, it confuses me more and more. I think it has a well-known meaning in cryptography, so what is it? They can usually use the limited number of ...
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1answer
82 views

Why every access structure is a multipartite access structure?

The set of authorized subsets of participants is called an access structure. In a multipartite access structure, the set of participants is divided into several parts and all participants in the ...
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1answer
50 views

Which of these deductions are true about the simulator and the adversary?

Which of these deductions make sense? The simulator is actually being run by the adversary. It makes sense that the adversary initializes the simulator (which is just a program) with the input that ...
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1answer
81 views

In “Lecture Notes on Cryptography” what does “PTM” mean?

I came across a handbook named "Lecture Notes on Cryptography" from Shafi Goldwasser and Mihir Bellare and I read their definition 3.1 about poly-time indistinguishability: Let $X_n,Y_n$ be ...
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1answer
70 views

The Collision Differential for MD4 - a question on notation (Wang, et al)

In the paper "Cryptanalysis of the Hash Functions MD4 and RIPEMD" the authors introduce the following notation (paragraph 4.1): $\Delta$$H_0$ = 0 $\xrightarrow{(M_,M')}$ $\Delta$$H$ = 0 What exactly ...
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1answer
109 views

What kind of information in cryptography is called semantic information?

I have been studying cognitive cryptography from this article. Its definition of cognitive cryptography is: Cognitive cryptography is a division of cryptography within which any information set ...
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0answers
61 views

Asymmetric encryption property required in an authentication protocol

We want to choose an asymmetric encryption scheme for use as follows: A device holds its private key, with the corresponding public key known and trusted by all. The device also holds a small $b$-bit ...
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2answers
6k views

Is there any difference between cryptography and cryptology?

Is there a difference between cryptography and cryptology, if any? An internet search suggests that both terms can be used interchangeably.
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1answer
2k views

What was NIST’s reason to switch naming from MD… (Message Digest) to SHA… (Secure Hashing Algorithm)?

When NIST introduced SHA-0 in 1993, they – for the first time – switched their naming convention from MD-n to SHA-n. Since both point to similar constructions (read: hashing algorithms with the same ...
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1answer
57 views

What is the name of this method?

Say I have a $26\times 26$ matrix $M$, each column$C_i$ of which contains the numbers from 1 to 26 in a random order. To encrypt a word, I take the first letter (e.g., b), convert it to its index $i$ (...
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2answers
260 views

Functional difference between stream cipher, XOF, seed expander, KDF, etc

This question is a request for terminology clarification. In a canonical XOF interface, the output can be extended as much as needed, but does input has to be variable-length or can be fixed-length ...
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0answers
102 views

Formal taxonomy for cryptographic vulnerabilities

There are several areas in which cryptographic vulnerabilities can be introduced. Length extension attacks are inherent to hash functions using Merkle–Damgård. Heartbleed was a vulnerability caused ...
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1answer
60 views

Is a signature scheme using a hash considered a hybrid cryptosystem?

In Wikipedia there is a page on hybrid cryptosystems. However, although cryptography contains a lot more than just encryption, only hybrid encryption using key encapsulation and data encapsulation is ...
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1answer
122 views

Discrete Logarithm Notation

Im studying for my final, and some of the practice problems that I have found have discrete logarithms in this notation $L_n(p)$. What does this notation equate to? For example:
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1answer
126 views

What is the “standard model” for block ciphers?

In this paper and this the authors speak of a "standard model". What is the "standard model"? How does it differ from the "ideal model"? Why does the decision to use it or the "ideal model" impact the ...
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3answers
177 views

Would this hash functionality fall under pre-image resistance or collision resistance?

I understand that there are three main security requirements for hash functions, pre-image resistance, second pre-image resistance and collision resistance. I need to write about a hash function that ...
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1answer
1k views

What exactly is a “security parameter”?

I often encounter the term “security parameter” when I read crypto related stuff. My basic understanding is that it just denotes some bit-length however, I'm not so sure. For example, when it says ...
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1answer
4k views

What is “Fast Prime”?

In this note, the manufacturer of a RSA key generation gizmo vulnerable to the new ROCA attack (see second section) explains that it is common practice to employ acceleration algorithms in order to ...
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3answers
184 views

Why are processes requiring (almost) as much work as brute force considered an “attack” on a hash function?

In the literature on attacks against hash functions, I frequently come across algorithms requiring $2^n$ work described as being preimage or collision "attacks" on a hash function with only marginally ...
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2answers
237 views

Components of Cryptanalysis

What are different components of Cryptanalysis. I can't seem to find them. Are they the same as Cryptosystem or is there any difference.
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15k views

What is the difference between a digest and a hash function?

I was wondering about the difference between these two terms... What is the difference between a digest and a hash function?
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1answer
137 views

Idiomatic description for an adversary in possesion of a quantum computer?

I was wondering what the "accepted" way is to describe an adversary who: is in possession of a quantum computer with which they can efficiently run quantum algorithms such as Grover's or Shor's ...
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4answers
1k views

When is an RNG a CSPRNG, a CSRNG, or a TRNG?

In a recent answer to a question about CSPRNGs, it was stated that… Nondeterministic algorithms where there is no such requirement, and ideally could be replaced by a true random generator. ...
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1answer
797 views

Key Exchange & key Distribution in symmetric key cryptography

I want to know whether there is a difference between key exchange & key distribution in private key cryptography as well as public key cryptography? or is it the same term?
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1answer
230 views

What kind of encryption function is also used for decryption?

Is there a name for the particular type of encryption algorithm or function which is the same algorithm or function used for decryption? This is a vocabulary question, because I'm largely unfamiliar ...