• RSS
  • Twitter
  • FaceBook

Security Forums

Log in

FAQ | Search | Usergroups | Profile | Register | RSS | Posting Guidelines | Recent Posts

Tricky Math Question Involving Password Attempts

Users browsing this topic:0 Security Fans, 0 Stealth Security Fans
Registered Security Fans: None
Post new topic   Reply to topic   Printer-friendly version    Networking/Security Forums Index -> General Security Discussion

View previous topic :: View next topic  
Author Message
lmill152
Just Arrived
Just Arrived


Joined: 03 Oct 2010
Posts: 0


Offline

PostPosted: Sun Oct 03, 2010 9:19 pm    Post subject: Tricky Math Question Involving Password Attempts Reply with quote

Wasn't sure where else to put this question so I put it in here, please let me know if this fits better in another forum category. Here is the question, any help is appreciated.

Assume that passwords are selected from four-character combinations of 26 alphabetic characters. Assume that an adversary is able to attempt passwords at a rate of one per second.
a. Assuming no feedback to the adversary until each attempt has been completed, what is the expected time to discover the correct password?
b. Assuming feedback to the adversary flagging an error as each incorrect character is entered, what is the expected time to discover the correct password?
Back to top
View user's profile Send private message
SifuMike
Deceased
Deceased


Joined: 17 May 2004
Posts: 16777146
Location: Vancouver (not BC) WA (not DC)

Offline

PostPosted: Sun Oct 03, 2010 9:31 pm    Post subject: Reply with quote

Password Recovery Speeds
How long will your password stand up


http://www.lockdown.co.uk/?pg=combi

Quote:
This document shows the approximate amount of time required for a computer or a cluster of computers to guess various passwords. The figures shown are approximate and are the maximum time required to guess each password using a simple brute force "key-search" attack, it may (and probably will) be possible to guess correctly without trying all the combinations shown using other methods of attack or by having a "lucky guess".




How Long Would it Take to Brute Force Crack Your Password?
http://www.geeknews.net/2008/11/10/how-long-would-it-take-to-brute-force-crack-your-password
Back to top
View user's profile Send private message
lmill152
Just Arrived
Just Arrived


Joined: 03 Oct 2010
Posts: 0


Offline

PostPosted: Sun Oct 03, 2010 9:53 pm    Post subject: Reply with quote

Thanks!
Back to top
View user's profile Send private message
Dezaxa
Forum Fanatic
Forum Fanatic


Joined: 22 Mar 2007
Posts: 16777214


Offline

PostPosted: Fri Oct 08, 2010 1:53 pm    Post subject: Reply with quote

Sounds like we're being asked to do someone's homework here, but I think the answers are 228488 and 52 respectively.
Back to top
View user's profile Send private message
SifuMike
Deceased
Deceased


Joined: 17 May 2004
Posts: 16777146
Location: Vancouver (not BC) WA (not DC)

Offline

PostPosted: Fri Oct 08, 2010 7:09 pm    Post subject: Reply with quote

Yes, it does sound liike a homework assignment, but the information is usefull to anyone making passwords and wondering about the password length.
Back to top
View user's profile Send private message
Display posts from previous:   

Post new topic   Reply to topic   Printer-friendly version    Networking/Security Forums Index -> General Security Discussion All times are GMT + 2 Hours
Page 1 of 1


 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

Community Area

Log in | Register