well ya how a message is encrypted by using a point. but some how I have
managed to find a solution.and yes its possible to find y if the values of x
are given.
1. in a finite field p select x, ( 0<x<p )
2. Test x value to see if z=x^3+bx+c mod p is quadratic residue (q)
applying Euler's criterion
3. Using Euler's criterion , find qr=z^[(p-1)/2] mod p
(if qr =1 then it is quadratic residue modulo p)
4. Finally the formula to find y using formula z^[(p+1)/4]mod p.
this is how u find y after selecting x. Correct if I am wrong.
On Fri, Jan 23, 2009 at 8:45 PM, Gung Shi Jie <[email protected]> wrote:
>
> Do you mean you find a point (x,y) on the curve and encrypt message
> using x,y as key?
>
> Whether yes or no, that is what I am trying to do.
>
> The problem is, how do I find a point on a curve? Now I can only use
> Elliptic Curve Builder to generate random points.
>
> Also, can I give x, curve parameter and find y?
>
> Thanks.
>
> On Jan 20, 5:02 am, "Wei Dai" <[email protected]> wrote:
> > Representing a message as a point is not implemented in Crypto++. The
> ECIES
> > encryption algorithm in Crypto++ using elliptic curve to establish
> arandom
> > symmetric key, and then uses that to encrypt the message as bytes, not as
> a
> > point.
> Where could I find this code?
>
>
> >
>
--
Nauman Abdullah
MS( IS -6 )
Military College Of Signals
NUST
0300-6819189
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