# Cryptography in RSA

1. Prove that the RSA Cryptosystem is insecure against a chosen ciphertext attack: Given a

ciphertext y, describe how to choose a ciphertext y(hat)≠y such that the knowledge of the

plaintext x(hat)=d_k (y(hat)) allows you to compute x=d_k (y). Hint: First prove that in the RSA

Cryptosystem ,e_k (x_1 ) e_k (x_2 )modn=e_k (x_1 x_2 modn).

https://brainmass.com/math/combinatorics/cryptography-rsa-474240

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Proof:

We have the cipher text and we want to find its plaintext , such that or . If we choose a specific ...

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The expert examines cryptography in RSA.

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