(Unicode C++) Convert Java KeyStore to PKCS12 / PFX

Loads a Java keystore file and saves it as a PKCS12 / PFX. A Java keystore (JKS) can contain two types of entries: (1) trusted root certificates or (2) private keys + cert chains. Usually a JKS will contain all entries of one type or another (and thus a particular JKS serves one purpose or another; meaning that a JKS containing trusted roots is used as a source for verifying pre-trusted roots, and a JKS containing private keys (and cert chains) is used as a secure, encrypted store for private keys).

A PKCS12 / PFX typically contains one or more private keys, along with each private key's certificate chain. Therefore, it typically makes sense to only write the private key entries to a PKCS12 (and the associated certificate chains). If a JKS contains trusted root certificates, it makes more sense to conver it to a PEM file (such as the CA cert bundle in PEM format from mozilla.org).

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#include <CkJavaKeyStoreW.h>
#include <CkPfxW.h>
#include <CkPrivateKeyW.h>
#include <CkCertChainW.h>

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

    CkJavaKeyStoreW jks;

    const wchar_t *jksPassword = L"myJksPassword";

    // Load the Java keystore from a file.  The JKS file password is used
    // to verify the keyed digest that is found at the very end of the keystore.
    // It verifies that the keystore has not been modified.
    bool success = jks.LoadFile(jksPassword,L"/someDir/keyStore.jks");
    if (success != true) {
        wprintf(L"%s\n",jks.lastErrorText());
        return;
    }

    // To convert, we'll access the private key entries
    // from the JKS, add each to the PKCS12, and then save the PKCS12.
    CkPfxW pkcs12;

    int numPrivateKeys = jks.get_NumPrivateKeys();
    int i;

    CkPrivateKeyW *privKey = 0;
    CkCertChainW *certChain = 0;

    // For each private key entry, get the private key and
    // the associated certificate chain.
    // Each private key is password protected.  Usually it is the same
    // password as used for the keyed digest of the entire JKS.  
    // However, this does not have to be.  The password is passed
    // here to handle the possibility of each private key requiring
    // a different password.
    i = 0;
    while (i < numPrivateKeys) {
        privKey = jks.GetPrivateKey(jksPassword,i);
        wprintf(L"%s\n",jks.getPrivateKeyAlias(i));
        certChain = jks.GetCertChain(i);

        // Add the private key and it's associated certificate chain to the PKCS12.
        success = pkcs12.AddPrivateKey(*privKey,*certChain);
        if (success != true) {
            wprintf(L"%s\n",pkcs12.lastErrorText());
            delete certChain;
            delete privKey;
            return;
        }

        delete certChain;
        delete privKey;
        i = i + 1;
    }

    // Save the PKCS12 / PFX to a file.
    // The password can be the same as the JKS password, or something new.
    // (With the PKCS12 format, there is a single password for the entire contents
    // of the file.  With the JKS format, there is flexibility in allowing each private key
    // to have it's own password.)
    const wchar_t *pkcs12Password = L"myNewPassword";
    success = pkcs12.ToFile(pkcs12Password,L"/pkcs12_files/myPfx.p12");
    if (success != true) {
        wprintf(L"%s\n",pkcs12.lastErrorText());
    }
    else {
        wprintf(L"Successfully saved to PKCS12 format.\n");
    }
    }