Unicode 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. Unicode C

#include <C_CkEccW.h>
#include <C_CkPrngW.h>
#include <C_CkPrivateKeyW.h>
#include <C_CkAsnW.h>
#include <C_CkXmlW.h>
#include <C_CkCrypt2W.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkEccW ecc;
    HCkPrngW fortuna;
    const wchar_t *entropy;
    HCkPrivateKeyW privKey;
    HCkAsnW asn;
    HCkXmlW xml;
    HCkCrypt2W crypt;
    const wchar_t *privKeyHex;

    success = FALSE;

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

    ecc = CkEccW_Create();

    // 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.
    fortuna = CkPrngW_Create();
    entropy = CkPrngW_getEntropy(fortuna,32,L"base64");
    success = CkPrngW_AddEntropy(fortuna,entropy,L"base64");

    privKey = CkPrivateKeyW_Create();
    success = CkEccW_GenKey(ecc,L"secp256k1",fortuna,privKey);
    if (success == FALSE) {
        wprintf(L"%s\n",CkEccW_lastErrorText(ecc));
        CkEccW_Dispose(ecc);
        CkPrngW_Dispose(fortuna);
        CkPrivateKeyW_Dispose(privKey);
        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.)

    asn = CkAsnW_Create();
    success = CkAsnW_LoadEncoded(asn,CkPrivateKeyW_getPkcs1ENC(privKey,L"base64"),L"base64");
    if (success != TRUE) {
        wprintf(L"%s\n",CkAsnW_lastErrorText(asn));
        CkEccW_Dispose(ecc);
        CkPrngW_Dispose(fortuna);
        CkPrivateKeyW_Dispose(privKey);
        CkAsnW_Dispose(asn);
        return;
    }

    xml = CkXmlW_Create();
    CkXmlW_LoadXml(xml,CkAsnW_asnToXml(asn));

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

    // 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.
    crypt = CkCrypt2W_Create();
    privKeyHex = CkCrypt2W_reEncode(crypt,CkXmlW_getChildContent(xml,L"octets"),L"base64",L"hex");

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


    CkEccW_Dispose(ecc);
    CkPrngW_Dispose(fortuna);
    CkPrivateKeyW_Dispose(privKey);
    CkAsnW_Dispose(asn);
    CkXmlW_Dispose(xml);
    CkCrypt2W_Dispose(crypt);

    }