Baby-step Giant-step

A Collision Algorithm that finds the same number between 2 sets to solve the DLP which looks like: $a^x\equiv b\mathrm{mod}N$ These 2 sets are created as follows:

1. Choose a random integer $k$
2. Create a set ‘A’ of all numbers $a,a^2,a^3,\dots ,a^{k-1}$
3. Create a set ‘B’ of all numbers $b{a}^{-k},b{a}^{-2k},\dots ,b{a}^{-rk}$ where rk > N If the DLP has a solution, then there should be a number common between sets A and B.