Assume I want to make my RSA secure because I heard that textbook RSA, especially in conjunction with low exponents, is very risky. I decide to limit my message length to 100 and subsequently construct my padded message as follows:
m = '\x01'*70 + m + '\x01'*70
To improve performance, I choose $e=3$.
Why is this risky? After all, the padded message is large enough, i.e. knowing that $c=m^3 + k*n$, $k$ will be too high to bruteforce. At first glance I don't see any attacks that could work here therefore it should be safe?