Show how one can decrypt RSA message with e = 3 and $m<N^{1/3}$ without knowing the private key

Question

Show how one can decrypt RSA message with e = 3 and $m<N^{1/3}$ without knowing the private key.

I really don't know how to solve this one.

we just learned about quadratic residues so i guess it has something to do with that.

First thing is I need to understand what do I know and what do I need to find.

after reading some about RSA I think I need to find x for the following congruence-

$c \equiv x^3 \pmod N$

where I know c, and N

is that correct? any help , clues , solutions or more information will be appriciated

Answer 1

Hint: If $m<N^{1/3}$ then $m^3<N$. What does this tell you about $m^3\bmod N$?