C++

Generate ECDSA Key and Get Details as XML

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Demonstrates how to generate an ECDSA key and gets the parts as XML. C++

#include <CkEcc.h>
#include <CkPrng.h>
#include <CkPrivateKey.h>
#include <CkAsn.h>
#include <CkXml.h>
#include <CkCrypt2.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  This requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    CkEcc 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.
    CkPrng fortuna;
    const char *entropy = fortuna.getEntropy(32,"base64");
    success = fortuna.AddEntropy(entropy,"base64");

    CkPrivateKey privKey;
    success = ecc.GenKey("secp256k1",fortuna,privKey);
    if (success == false) {
        std::cout << ecc.lastErrorText() << "\r\n";
        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.)

    CkAsn asn;
    success = asn.LoadEncoded(privKey.getPkcs1ENC("base64"),"base64");
    if (success != true) {
        std::cout << asn.lastErrorText() << "\r\n";
        return;
    }

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

    std::cout << xml.getXml() << "\r\n";

    //  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.
    CkCrypt2 crypt;
    const char *privKeyHex = crypt.reEncode(xml.getChildContent("octets"),"base64","hex");

    std::cout << "EC private key as hex = " << privKeyHex << "\r\n";
    }