Unicode C++

Get Public Key from CSR

See more CSR Examples

Demonstrates how to get the public key from a CSR. Unicode C++

#include <CkPemW.h>
#include <CkAsnW.h>
#include <CkXmlW.h>
#include <CkBinDataW.h>
#include <CkPublicKeyW.h>

void ChilkatSample(void)
    {
    bool success = false;

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

    CkPemW pem;

    // No password is required.  Pass an empty password string..
    const wchar_t *noPassword = L"";
    success = pem.LoadPemFile(L"qa_data/csr/csr2.pem",noPassword);
    if (success != true) {
        wprintf(L"%s\n",pem.lastErrorText());
        return;
    }

    const wchar_t *strBase64 = pem.getEncodedItem(L"csr",L"",L"base64",0);

    CkAsnW asn;
    success = asn.LoadEncoded(strBase64,L"base64");
    if (success != true) {
        wprintf(L"%s\n",asn.lastErrorText());
        return;
    }

    // Convert the ASN.1 to XML.
    CkXmlW xml;
    success = xml.LoadXml(asn.asnToXml());
    wprintf(L"%s\n",xml.getXml());
    wprintf(L"----\n");

    const wchar_t *strModulusHex = xml.getChildContent(L"bits");
    wprintf(L"strModulusHex = %s\n",strModulusHex);
    wprintf(L"----\n");

    // We need the modulus as base64.
    CkBinDataW bd;
    bd.AppendEncoded(strModulusHex,L"hex");
    const wchar_t *modulus64 = bd.getEncoded(L"base64");
    wprintf(L"modulus64 = %s\n",modulus64);
    wprintf(L"----\n");

    // Build the XML for the public key.
    CkXmlW xmlPubKey;
    xmlPubKey.put_Tag(L"RSAPublicKey");
    xmlPubKey.UpdateChildContent(L"Modulus",modulus64);
    // The RSA exponent will always be decimal 65537 (base64 = AQAB)
    xmlPubKey.UpdateChildContent(L"Exponent",L"AQAB");

    wprintf(L"RSA public key as XML:\n");
    wprintf(L"%s\n",xmlPubKey.getXml());
    wprintf(L"----\n");

    // Load the XML into a Chilkat public key object.
    CkPublicKeyW pubkey;
    success = pubkey.LoadFromString(xmlPubKey.getXml());
    if (success != true) {
        wprintf(L"%s\n",pubkey.lastErrorText());
        return;
    }

    // Show the public key as PEM.
    bool preferPkcs1 = true;
    wprintf(L"%s\n",pubkey.getPem(preferPkcs1));
    }