> Now what I would like to do is to be able to generate my own customly
> defined elliptic curve and display its name and domain parameters on
> screen in an easier way... I would appreciate if anyone could provide
> any further source code examples and / or advice.
>
Not exactly what you need, but that's what I use to generate private
keys with custom curves defined by output of Schoof's Algorithm
implementation
(schoof.exe, http://www.shamus.ie/index.php?page=elliptic-curves)
Generating a curve:
schoof.exe -o out.txt -h -d -s [P] [A] [B]
(P, A, B are your input parameters)
Output file format will be
size
P
A
B
N
X
Y
G is a point on a curve, CryptoPP (ECP::Point) expects it in this form:
"04[X][Y]"
First a helper class, to convert hex strings into more C++ friendly types:
struct EcCustomParameters
{
EcCustomParameters(const char* p, const char* a, const char* b,
const char* g, const char* n, unsigned int k)
{
StringSource ssP(p, true, new HexDecoder);
StringSource ssA(a, true, new HexDecoder);
StringSource ssB(b, true, new HexDecoder);
curve = ECP(Integer(ssP, (size_t)ssP.MaxRetrievable()),
ECP::FieldElement(ssA, (size_t)ssA.MaxRetrievable()),
ECP::FieldElement(ssB, (size_t)ssB.MaxRetrievable()));
StringSource ssN(n, true, new HexDecoder);
N.Decode(ssN, (size_t)ssN.MaxRetrievable());
StringSource ssG(g, true, new HexDecoder);
curve.DecodePoint(G, ssG, (size_t)ssG.MaxRetrievable());
K = k;
}
Integer N, K;
ECP curve;
ECP::Point G;
};
Then defining domain parameters:
EcCustomParameters p("PPP", "AAA", "BBB", "04XXXYYY", "NNN", 1);
Then creating CryptoPP domain parameters:
DL_GroupParameters_EC<ECP> params(p.curve, p.G, p.N, p.K);
Then generating private key:
ECIES<ECP>::PrivateKey key;
key.Initialize(rng, params);
I'm sure you can use similar approach for EC2N.
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