May 18, 2021

Every bit can be one or zero, but if you reduce the domain there are fewer bits and therefore less entropy. A 132 bit buffer has 132 bits of entropy as entropy is not just the 1 bits. If you reduce the domain then it reduces the strength of the seed, even if the actual value was just 1. 1 out of 2^1 is 50%, 1 out of 2^132 is much smaller.