> I feel like 128 bits is a lot for address space but not enough for encryption. Yes, collisions take sqrt(2^128) = 2^64 operations to find on average. Usually

> I feel like 128 bits is a lot for address space but not enough for encryption. Yes, collisions take sqrt(2^128) = 2^64 operations to find on average. Usually 256 bits is chosen to make that 2^128 operations if finding a collision poses problems.