Security and unintended leakage of information


[image of code keypad]

A security access keypad

An interesting aspect of online security is how information leaks out of systems in unintended and unexpected ways. The problem is not, of course, limited to online security – it exists in the physical world as well.

Here is an image of a security access keypad. It controls access to a private parking area at the back of my house.

Maybe not quite as secure as intended…

12 thoughts on “Security and unintended leakage of information

  1. 4! combinations means up to 24 tries. If that lock is worth it’s money, there’s a timedelay as soon as a wrong code is entered 3 times in a line.

  2. this is why, when typing a windows password, the third or fourth subsequent wrong password has a long delay where it “tries” to login (with the aero “hour glass circle”) but still returns a failure at the end.

  3. 4! would be 4 factorial, or 4x3x2x1. I don’t think that that is an accurate assessment. First you would have to know that it only uses 4 digits, it is possible that the code is 8 digits, but they are used multiple times. I think an accurate assessment would be 4x4x4x4 if it is indeed limited to a length of 4 digits. It would grow exponentially larger as you added digits though. It surely isn’t secure, and maintained by a lazy person who has decided not to use a revolving password or a rag/cleaner. : (

  4. My guess is that the combination is 1953 – humans are so pathetic at choosing random numeric digits, and tend to go with things like the year of their birth.

  5. If it’s a 4 cipher coder, there’s only 10 options (since we know that four keys are used)

    I bet it’s either 1593, 3159, 9513 or 3951, since most people organize it as a pattern…

  6. Well, assuming 4 keys in a password, and a total 4 keys pressed, each key is only used once.
    1359
    1395
    1539
    1593
    1935
    1953
    3159
    3195
    3519
    3591
    3915
    3951
    5139
    5193
    5319
    5391
    5913
    5931
    9135
    9153
    9315
    9351
    9513
    9531
    Yup, 24,

  7. Those are a lot of assumptions. You can’t assume it’s 4 digits or that repeating digits isn’t allowed. That blows your theory of 24 possibilities out of the water. Although looking up the manual for this device could shed some light for you noobs.

  8. Pingback: dy/dan » Blog Archive » My Lesson Plan: The Door Lock

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