# Guessing Number-Generating Algorithm

1. Sep 7, 2007

### caldiar

Hey everyone.

Before I get started on the actual problem, here's a quick background story:

Last year my math teacher gave out passwords to check grades online. They were constructed in the following manner - 1st initial, 2nd initial, random 1 digit number.

The students in the class made a game out of guessing each others passwords and turning them in to the teacher for extra credit.

My teacher loves math. If I had to guess her favorite branch of math I'd say number theory. She saw how popular the password-guessing was last year so she decided to give us a challenge this year and told us she used an algorithm to make these passwords and she then encouraged us to try to figure out what she did to make the passwords.

So here's where the story ends and the problem begins.

I have two classes with her. She gave me a different password for both classes each generated in the same method.

The relevant pieces of the passwords are: 11 and 911
I gathered a list of passwords from students willing to help figure out the algorithm.

(EDIT)It was discovered today that multiple algorithms were used for different sets of passwords (an algorithm for every 2-3 passwords actually). However, she told me it was kind of scary that I'm already at a point she thought I wouldnt be at for a few months... :)

She also requested that I dont post the passwords online.
(/EDIT)

Thanks,
Caldiar

Last edited: Sep 7, 2007
2. Sep 7, 2007

### chroot

Staff Emeritus
I've read your post twice, and I still do not see anything resembling a question here. What exactly are you hoping that we will do with nothing but the numbers 11 and 911?

- Warren

3. Sep 7, 2007

4. Sep 7, 2007

### caldiar

Well, I came to the site on my own after spending a few hours researching various algorithms.

My teacher said that if I DID find ANY of the 15 algorithms I needed to tell her and she would change the passwords using the cracked algorithm to protect confidentiality.

Normally this still would be unacceptable but you must understand that the school Im at is about 90 students large and everybody knows everybody. We have a very close bond as students and think of each other as family. Plus, for me to crack an algorithm the student has to give me his or her password in the first place for me to use in finding patterns so there would be no involuntary release of information.

5. Sep 7, 2007

### ramsey2879

Did the people who gave you their pass word also give you permission to post it on the internet? Wouldn't it seem that if there was an algorithm for one individuals password that the same algorithm might have been used to generate anothers password who did not give you their password? I still think that your teacher did something very foolish and that you should never try to access someone elses persoal information or make it possible for others to do so no matter how close your group is.

Last edited: Sep 7, 2007
6. Sep 7, 2007

### caldiar

Only 2-3 passwords are generated with the same algorithm.

On another note, I'd very much like to have this thread deleted since it provides nothing useful to this forum and is wasting space. =)

Last edited: Sep 7, 2007
7. Sep 7, 2007

### ramsey2879

That is no excuse for comprimising a persons fundamental right to privacy. If one persons right to privacy is comprimised that is one too many. While the chance may have been low that any of your fellow students read this thread there was that chance. Plus you seem to be an honorable person since you did delete the passwords. How do you know that only 2-3 passwords are generated by the algorithm(s)? Perhaps there is in fact no algorithm except a random number generator and your teacher was merely teasing the class. I wouldn't take the right to privacy so lightly as you say your teacher has nor would I engage in a challenge of discovering an algorithm that should be known only to the teacher and otherwise kept confidential. I too am done with this thread and think it should be moved to another forum but not deleted.

Last edited: Sep 7, 2007