Questions on cryptography and cryptanalysis, encryption and decryption, and the making and breaking of codes and ciphers.
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Discrete Logarithm
If $p$ is a prime and $a,b$ are integers not divisible by $p$ such that $a^x \equiv b \pmod p$ with $0 ≤ x < o_p(a)$, then we define $x = L_a(b)$ and say $x$ is the discrete logarithm of $b$ ...
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2answers
42 views
Expectation of characters in a string
What is the expected distance between two ’e’s in a random character stream where ’e’s occur 11% of the time?
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2answers
286 views
Calculate an encoding matrix from inputs and outputs
I have a list of inputs and outputs of what I believe is encoded with a matrix (similar to this method). I was wondering if its possible to reproduce the matrix used to transform the inputs into the ...
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1answer
22 views
congruence modulo and equality
why in cryptography most of the equalities written in the form of
$$a:=b$$
why not we write $a=b$
why in congruence modulo $a \equiv c \pmod b$ that bracket is put. Is it refers the priority.
can ...
0
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1answer
39 views
Perfect Secrecy, Encryption
An encryption scheme $(\mathrm{Gen},\mathrm{Enc},\mathrm{Dec})$ over a message space $M$ is perfectly secret if and only if for every probability distribution over $M$, every message $m\in M$, and ...
0
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1answer
122 views
How many arguments are there in a Merkle tree?
I want to calculate the amount of elements in a Merkle tree given the number of leaf elements.
The number of elements at a given level n is equal to number of elements at a level n+1, divided by two ...
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1answer
242 views
Digital Signatures with message recovery - do they provide confidentiality?
I've lately found about digital signatures with message recovery.
I was wondering, in what degree do these signatures provide confidentiality of the message (if they do at all) ? I've briefly read a ...
