¹The effective security measures the amount of work it takes to break a cryptosystem by comparing it with the amount of work required to carry out a brute force attack on a cryptosystem with keys of that length. Thus, a cryptosystem that can be broken in time 2⁹⁰ is said to have 90-bit effective security, even if the actual key length is much greater, since it is no more secure than a system with a 90-bit key.