Hi I need little help here

Here is my given string "8f43ae1a3319c649cc57408b6a392d6b"

8f xor 33 xor cc xor 6a =1a
43 xor 19 xor 57 xor 39 =34
ae xor c6 xor 40 xor 2d =05
1a xor 49 xor 8b xor 6b =b3

1a3405b3 and 1ffffff or 2000000 = 23405B3


How to apply that using C#?