The pseudo-random-function tag has no wiki summary.
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pseudo random sequence and permutation functions [closed]
Iam doing my Master thesis in enhancing of an encryption algorithm by using of a pseudo random sequence generators to create a 16*16 shared table and apply a permutation function on it. one of the ...
2
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1answer
72 views
Question about the definition of a secure PRF
I'm taking a cryptography introduction course, and we're covering the definition of a secure PRF.
I understand the test goes as follows: A challenger picks a function $f$ such that
$f \leftarrow ...
0
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1answer
42 views
Could use an explanation of the notation for an oracle adversary
In the definition below, what exactly does it mean for the adversary (not even sure that's the correct term?) to equal one?
$$
\underset{K}{Pr} \left [A^{F_k(\cdot)} = 1 \right ]
$$
Source (Page ...
0
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2answers
138 views
Generate random number which should depend on key
i want to generate random number for example from [1..100].
This algorithm which generates random number should work similarly like ("Linear congruential generator").
Here:
c - increment should ...
2
votes
1answer
102 views
What is an oracle adversary?
I'm trying to figure out block ciphers and this is the first time I've encountered the term "oracle adversary". It appears in the context of defining a PRP and a PRF. Can someone please explain what ...
8
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3answers
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How to construct a good PRF from a block cipher?
We want to explicitly construct a good (as tentatively defined below) Pseudo-Random Function $F$ with $b$-bit input and output, from (preferably just) one Pseudo-Random Permutation $E$ of $b$-bit, as ...
2
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2answers
135 views
Proof that a function constructed from a PRP is, or is not a PRF?
Let $E$ be a family of Pseudo-Random Permutations of $b$ bits, with $E_K$ indistinguishable from random permutation with effort less than $O(2^b)$, easily computable as well as the inverse ...
-1
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1answer
91 views
Pseudo-random Number generation for Passwords
i want to know what is the best pseudo-random number generation algorithm for passwords? for example my scenario is I have to generate 5K pseudo-random bits from a user-supplied password(6 ...
1
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0answers
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IND-CPA security scheme [duplicate]
Possible Duplicate:
CPA Secure Chosen plaintext scheme
The example for IND-CPA secure schemes given is generally:
for a random r,
$Enc_k(m) =(r|| E_k(r)$ $XOR$ $m)$ where $E$ is a $PRF$
...
5
votes
1answer
131 views
Goldreich-Goldwasser-Micali Construction
The Goldreich-Goldwasser-Micali construction allows to build a (cryptographically secure) pseudo-random function from of a (cryptographically secure) pseudo-random generator.
More formally, let $G: ...
2
votes
2answers
125 views
Does a hash function in chaining mode or in counter mode make a better pseudo-random number generator?
I have two pseudorandom generators:
$f_1$ takes a random seed $l_0||r_0$ $\in \{0,1\}^{160}$ as input and outputs $r_1||r_2|| \dots ||r_k$, where $l_i||r_i = \operatorname{SHA-1}(l_{i-1}||r_{i-1})$ ...
0
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1answer
155 views
Cryptographically strong pseudo-random seq. generators
If a pseudo-random sequence generator is built so that it uses an n-bit seed and outputs a string that is of length x. Let's say one wants to generate a bit string of length y and uses the previous ...
1
vote
1answer
1k views
Cryptographic security of PHP mt_rand() function using Mersenne Twister algo
At stackoverflow this question has been asked. It uses additional random entropy and a hash method (among others) to try and create a cryptographically secure pseudo-random number generator for PHP. ...
1
vote
3answers
178 views
Realize a MAC using a Pseudo-random function?
Given a pseudo-random function and assuming that we do not have any other tools,
How can we construct a MAC?
I believe this can be done. Would like to know if there is more than one way of doing ...
