Tagged Questions

Questions on cryptography and cryptanalysis, encryption and decryption, and the making and breaking of codes and ciphers.

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Does the difficulty of discrete logarithm depend on the difficulty of integer factorization?

The security of many (most? all?) public-key cryptography systems are based on the difficulty of the discrete logarithm or integer factorization. Are these two problems related at all? With the ...
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If the plaintext is “HELPMEAR” and the block size is 5, determine the key

We first add on 2 random characters XX to the end to make the number of characters equal to 10. So we get: HELPMEARXX which we can seperate into. (I think) XXRAE MPLEH So the key should be 2 ...
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Markov Chain and cryptanalysis

Where I will be able to found papers to read the state-art of the use that Markov chain in cryptanalysis. I founded this Canteaut, A. and Chabaud, F. (1998). A new algorithm for finding ...
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cryptographyVs matrices

I need a good example(s) and justification to the following. If any one can help, I am so glad to them. I understand the original computation. However, I am little confused in writing coding and ...
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public key crypto

Okay, i have basic knowledge of public key crypto and factoring but: assume i have LOTS of high value sites I want to attack, lets say banks. Each has a public key pq to crack assume I gather all ...
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Cryptoanalysis of RSA

I am having trouble with this problem: Suppose that you would like to use the RSA system to send the secret message $P$ to a colleague across an insecure line of communication. Assume that you ...
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Showing Elliptic Curves are irreducible

Suppose an elliptic curve defined over a field $K$ has form $y^2 + h(x)y = f(x)$ where $h(x), f(x) \in K[x]$. $h(x)$ has degree 0 or 1 and $f(x)$ has degree 3 or 4. Moreover, this equation is ...
I am working on the product of two perfect crypto-systems and I need to prove that the product is secure. $$a -- [\text{system}\ 1] -- b -- [\text{system}\ 2] -- c$$ How can I prove that \$H(a) = ...