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Originally Posted by taos
Uhmm I'm not expert in Delphi (ASM is better) but g,y are TECPoint data types.
Tecpoint is a record
:TECPoint = Record
XCoordinate, YCoordinate : TFGInt;
Infinity : Boolean;
You can manipulate TECPOINT to convert to string ( ECPointToECPointString) or reverse (ECPointStringToECPoint). TEcpoints are this y^2 = x^3 + a*x + b and they are points on a elliptic curve.
Maybe this can help you:
ECPointKMultiple(g, p, a, x, y);
'Code:
Begin
// setting up parameters
writeln('setting up EC parameters ...');
Base256StringToFGInt('222222aatzzzznnn', p);
ok := true;
While ok Do
Begin
FindPrimeGoodCurveAndPoint(p, a, b, h, n, 60, g);
IsECSuperSingular(p, a, b, ok);
If ok Then
Begin
FGIntDestroy(a);
FGIntDestroy(b);
FGIntDestroy(h);
FGIntDestroy(n);
ECPointDestroy(g);
End;
End;
Base256StringToFGInt('ergezam', x);
ECPointKMultiple(g, p, a, x, y);
Base10StringToFGInt('63557', k);
Base2StringToFGInt('1', one);
FGIntGCD(k, n, temp);
While Not (FGIntCompareAbs(one, temp) = Eq) Do
Begin
FGIntDestroy(temp);
FGIntAddBis(k, one);
FGIntGCD(k, n, temp);
End;
FGIntDestroy(temp);
FGIntDestroy(one);
// with all these precautions everything is set up for signing/verifying
T := 'A black hole is a place where God divided by zero';
writeln('Signing the following string: ', T);
ECDSASign(T, p, a, x, n, k, g, r, s);
writeln('Verifying signature...');
ECDSAVerify(T, r, s, p, a, n, g, y, ok);
If ok Then writeln('Verification complete: signature is valid') Else writeln('Signature is not valid');
FGIntDestroy(p);
FGIntDestroy(a);
FGIntDestroy(n);
FGIntDestroy(k);
FGIntDestroy(h);
FGIntDestroy(x);
ECPointDestroy(g);
ECPointDestroy(y);
readln;
'End CODE
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