Question

2. Trying the correctness of a password takes 1 millisecond in brute force attack. Assume that the user decides to use 6-character long password. For each of the following cases, find the total amount of time to try all possible passwords. (a) Lower-case letters are used (b) Lower or upper-case letters are used (c) Lower or upper-case letters or digits are used

Answer 1

Hey here is answer to your question.

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So as its given that length is 6 chars and checking each password takes 1 mili second.

1. all lower case so each place can have a to z and total 6 places are there

means 26 * 26 * 26 * 26 * 26 * 26 = > ( 26 ) ⁶ = > 30,89,15,776 mili second or 308916 seconds.

2. lower case plus upper case means now each place can have either a to z or A to Z means 52 possible chars for each place

means ( 52 ) ⁶ = > 19770609664 mili seconds

3 now add the digits as well that is 0 to 9 means 10 more chars we can set in password means 62 chars in total.

( 62 ) ⁶ = >  56800235584 mili seconds

mili seconds or seconds can be later changed in bigger unit of time.