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Comparing to this question, assume $C, M \in \mathbb Z^*_{n^2}$, $e \ge 3$, is it hard to compute $M$ that satisfies $C=M^e \mod n^2$ when $C$ and $(n, e)$ are given?

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Hint: $C=M^e \bmod n^2\implies C\equiv M^e \pmod n$. – fgrieu Feb 25 '13 at 7:19
@fgrieu Thank you for the hint! – phan Feb 26 '13 at 4:09

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