Invitation to Computer Science 8th Edition

Published by Cengage Learning
ISBN 10: 1337561916
ISBN 13: 978-1-33756-191-4

Chapter 8 - Exercises - Page 427: 5

Answer

No, it would not be feasible to generate and test all possible passwords of length 10 or less in under one week's time.

Work Step by Step

Total characters available: 26 uppercase letters + 26 lowercase letters + 10 digits + 3 special symbols = 65 characters. Total number of possible passwords of lengths 1 through 10: $ 65 + 65^2 + 65^3 + \ldots + 65^{10}$ - \( 65^1 = 65 \) - \( 65^2 = 4,225 \) - \( 65^3 = 274,625 \) - \( 65^4 = 17,851,625 \) - \( 65^5 = 1,160,355,625 \) - \( 65^6 = 75,423,115,625 \) - \( 65^7 = 4,902,502,515,625 \) - \( 65^8 = 318,662,561,515,625 \) - \( 65^9 = 20,713,066,497,515,625 \) - \( 65^{10} = 1,346,349,295,838,515,625 \) Sum of possible passwords \( \approx 1.371 \times 10^{18} \) passwords The password-cracking tool can test 10,000,000 passwords per second. So the total time required is the total number of passwords divided by 10,000,000. Time required: \( = \frac{1.371 \times 10^{18}}{10,000,000} \) \( \approx 1.371 \times 10^{11} \) seconds \( = \frac{1.371 \times 10^{11}}{60 \times 60 \times 24} \) \( \approx 1,587,500 \) days Since one week is 7 days, it's clear that testing all possible passwords of length 10 or less would take far longer than one week.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.