math question "n(n-1)/2"

[cyclops07]

In symmetric cryptography, the key must be "n(n-1)/2"...
does anybody knows why the formula must be "n(n-1)/2"...
anyone can explain bout the formula?

[cyclops07]

In symmetric cryptography, the key must be "n(n-1)/2"...
does anybody knows why the formula must be "n(n-1)/2"...
anyone can explain bout the formula?

[Showtime8000]

Ya know, I remember that formula from geometry class...... A triangular pattern?

Sorry Im still young and not too "in-tune" with math yet.

[Showtime8000]

Ya know, I remember that formula from geometry class...... A triangular pattern?

Sorry Im still young and not too "in-tune" with math yet.

[Jabberwocky]

well i don't know what it has to do with crypto, but that formula is used to find the sum of all numbers prior to n.

ex: if you want the sum of all numbers leading up to 10, then
10(9) / 2 = 45

is the same as
1+2+3+4+5+6+7+8+9 = 45

i hope that sheds some light on something.

[Jabberwocky]

well i don't know what it has to do with crypto, but that formula is used to find the sum of all numbers prior to n.

ex: if you want the sum of all numbers leading up to 10, then
10(9) / 2 = 45

is the same as
1+2+3+4+5+6+7+8+9 = 45

i hope that sheds some light on something.

[(V)/\><]

http://www.maths.mq.edu.au/~steffen/...ort/node7.html

i just found this on google, it gives good insight into anti/symmetric cryptography.

from what i know, coupled with this, i still can't think why the key must be n(n-1)/2.

should it be a function? like p = n(n-1)/2 . could it be used to transform some ascii string into some larger bit number?

in short, i don't know.

[(V)/\><]

http://www.maths.mq.edu.au/~steffen/...ort/node7.html

i just found this on google, it gives good insight into anti/symmetric cryptography.

from what i know, coupled with this, i still can't think why the key must be n(n-1)/2.

should it be a function? like p = n(n-1)/2 . could it be used to transform some ascii string into some larger bit number?

in short, i don't know.

[nabylbt]

I might try to explain this but first check this out:
http://www.iam.unibe.ch/~mseeberg/theory.html
http://www.informatik.uni-bremen.de/~hs/Lehre/L11.pdf

Basically, the stated formula on top is used to estimate the entropy of the encryption key, ie how easily the key used can be reversed .... somehow it's an approximation
hope that help

[nabylbt]

I might try to explain this but first check this out:
http://www.iam.unibe.ch/~mseeberg/theory.html
http://www.informatik.uni-bremen.de/~hs/Lehre/L11.pdf

Basically, the stated formula on top is used to estimate the entropy of the encryption key, ie how easily the key used can be reversed .... somehow it's an approximation
hope that help