Questions on the meaning, history, and usage of symbols and notation in cryptography. Please remember to mention where (book, paper, webpage, etc.) you encountered any notation you are asking about.
1
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1answer
185 views
What does $(\mathbb{Z}_n^*)^2$ mean?
In a paper they write once, $(\mathbb{Z}_n^*)^2$. Is this the group of quadratic residues or is it something else?
Here the theorem:
Under the strong RSA assumption, given a modulus $n$, along with ...
1
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1answer
201 views
What does the expression $1^n$ mean as a function argument?
In a paper about predicate encryption or attribute based encryption, the setup function is mentioned with the $setup(1^n)$ or $setup(1^l)$. I want to know what is meant here.
Is it multiples of ones ...
2
votes
1answer
110 views
Why does key generation take an input $1^k$, and how do I represent it in practice?
In my lecture, the lecturer said:
Let $K$ be the key generation algorithm. Given a security parameter represented in unary, $1^k$, $K(1^k)$ will output a keypair $(pk; sk)$, known as the public ...
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0answers
126 views
How can I become familiar with the logic syntax used in Cryptography papers? [closed]
I'm having to write a 5000 word essay on Cryptography, and many (if not all) of the papers I've read on the topics have logic syntax I simply don't understand.
How can I become familiar with the ...
2
votes
2answers
410 views
What exactly is a negligible (and non-negligible) function?
The mathematical definition of neglible and non-neglible functions is fairly clear-cut, but why they are important and how they are used in cryptography?
5
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3answers
265 views
What do $0^n$ and $1^n$ mean in cryptography?
EDIT : I added more context.
Let $f$ = {$f_k$} be a pseudo random function family.
Let $G(x)$ be a pseudo-random generator such that:
$G(x)$ = $f_x$($0^k$)$f_x$($1^k$) where k=$|x|$ .
I don't ...
2
votes
2answers
281 views
Why is a non fixed-length encryption scheme worse than a fixed-length one?
I have the following definition (highlights by me):
An (efficient secret-key) encryption scheme $(Gen,Enc,Dec)$, where $Gen$ and $Enc$ are PPT algorithms and $Dec$ is a Deterministic Polytime ...
1
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2answers
104 views
Standard symbol / notation for “x knows y”, or the inverse
What's the standard way to express "$x$ knows about $y$", or "$x$ has no knowledge of $y$" in cryptographic notation?
Example (PRNG predictor):
$\exists f : P(f(G(k)|_{0..n}) = G(k)|_{n+1}) \geq 0.5 ...
1
vote
1answer
181 views
ECIES protocol - what does the || operation mean?
I am studying elliptic curves problems, which also includes study of related protocols such as ECIES. A there is a problem I don't understand operation $||$. What this operation mean?
Some stuff is ...
