(Unicode C++) Generate ECDSA Key and Get Details as XML

Demonstrates how to generate an ECC key and gets the parts as XML.

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#include <CkEccW.h>
#include <CkPrngW.h>
#include <CkPrivateKeyW.h>
#include <CkAsnW.h>
#include <CkXmlW.h>
#include <CkCrypt2W.h>

void ChilkatSample(void)
    {
    //  This requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    CkEccW ecc;

    //  Generate a random ECC private key on the secp256k1 curve.
    //  Chilkat also supports other curves, such as secp384r1, secp521r1, and secp256r1.

    //  Create a Fortuna PRNG and seed it with system entropy.
    //  This will be our source of random data for generating the ECC private key.
    CkPrngW fortuna;
    const wchar_t *entropy = fortuna.getEntropy(32,L"base64");
    bool success = fortuna.AddEntropy(entropy,L"base64");

    CkPrivateKeyW *privKey = ecc.GenEccKey(L"secp256k1",fortuna);
    if (ecc.get_LastMethodSuccess() != true) {
        wprintf(L"%s\n",ecc.lastErrorText());
        return;
    }

    //  An EC private key has this ASN.1
    //  ECPrivateKey ::= SEQUENCE {
    //      version        INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
    //      privateKey     OCTET STRING,
    //      parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
    //      publicKey  [1] BIT STRING OPTIONAL (This is the ANSI X9.63 public key format.)

    CkAsnW asn;
    success = asn.LoadEncoded(privKey->getPkcs1ENC(L"base64"),L"base64");
    if (success != true) {
        wprintf(L"%s\n",asn.lastErrorText());
        return;
    }

    CkXmlW xml;
    xml.LoadXml(asn.asnToXml());

    wprintf(L"%s\n",xml.getXml());

    //  The XML looks like this:
    //  <?xml version="1.0" encoding="utf-8" ?>
    //  <sequence>
    //      <int>01</int>
    //      <octets>JgJvBG+3wletkJab8iXAkpz0O8/AgWZSpkYVcB7SpnU=</octets>
    //      <contextSpecific tag="0" constructed="1">
    //          <oid>1.3.132.0.10</oid>
    //      </contextSpecific>
    //  </sequence>

    //  The 32-byte private key is in the octets..
    //  Get it as hex.
    CkCrypt2W crypt;
    const wchar_t *privKeyHex = crypt.reEncode(xml.getChildContent(L"octets"),L"base64",L"hex");

    wprintf(L"EC private key as hex = %s\n",privKeyHex);

    delete privKey;
    }