Part 4: A suitcase has a combination lock with three wheels. Each wheel has ten
ID: 3542596 • Letter: P
Question
Part 4: A suitcase has a combination lock with three wheels. Each wheel has ten digits, 0 through 9. How many different combinations are there? Assume that a thief can try one combination every second, and that the thief will get lucky after trying about half the combinations, how long will it take the thief to open the briefcase?
If each wheel of the briefcase lock has the 16 hexadecimal digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 A, B, C, D, E, F, how many different combinations are there? How long will it take our thief to open the lock?
Part 5: Suppose that a lock like the one described above has only two numbers, 0 and 1, on the wheels, and there are eight wheels. How many combinations are there? What happens if a ninth wheel is added? How many combinations, and how long to "crack?"
Explanation / Answer
Part4
wheels 3, digits 10(0-9)
total combinations= 10*10*10= 1000
total time= 1000sec or 16 min 40sec
thief will open it in half time= 500sec or 8min20sec
if there are hexadecimal digits
wheels=3, digits=16(0-f)
total combinations= 16*16*16 =4096
total time= 4096 sec
time for thief to open= 2048sec = 34min 4sec
Part 5
wheels=8 number=2
total combination= 2^8=256
total time= 256 sec
thief will crack in= 128 sec ie 2min 8sec
Part 6
wheels=256 numbers=2
total combinations=2^256
total time=2^256
thief will crack in = 2^255