(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 <C_CkJavaKeyStore.h>
#include <C_CkPfx.h>
#include <C_CkPrivateKey.h>
#include <C_CkCertChain.h>

void ChilkatSample(void)
    {
    HCkJavaKeyStore jks;
    const char *jksPassword;
    BOOL success;
    HCkPfx pkcs12;
    int numPrivateKeys;
    int i;
    HCkPrivateKey privKey;
    HCkCertChain certChain;
    const char *pkcs12Password;

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

    jks = CkJavaKeyStore_Create();

    jksPassword = "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.
    success = CkJavaKeyStore_LoadFile(jks,jksPassword,"/someDir/keyStore.jks");
    if (success != TRUE) {
        printf("%s\n",CkJavaKeyStore_lastErrorText(jks));
        CkJavaKeyStore_Dispose(jks);
        return;
    }

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

    numPrivateKeys = CkJavaKeyStore_getNumPrivateKeys(jks);

    // 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 = CkJavaKeyStore_GetPrivateKey(jks,jksPassword,i);
        printf("%s\n",CkJavaKeyStore_getPrivateKeyAlias(jks,i));
        certChain = CkJavaKeyStore_GetCertChain(jks,i);

        // Add the private key and it's associated certificate chain to the PKCS12.
        success = CkPfx_AddPrivateKey(pkcs12,privKey,certChain);
        if (success != TRUE) {
            printf("%s\n",CkPfx_lastErrorText(pkcs12));
            CkCertChain_Dispose(certChain);
            CkPrivateKey_Dispose(privKey);
            CkJavaKeyStore_Dispose(jks);
            CkPfx_Dispose(pkcs12);
            return;
        }

        CkCertChain_Dispose(certChain);
        CkPrivateKey_Dispose(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.)
    pkcs12Password = "myNewPassword";
    success = CkPfx_ToFile(pkcs12,pkcs12Password,"/pkcs12_files/myPfx.p12");
    if (success != TRUE) {
        printf("%s\n",CkPfx_lastErrorText(pkcs12));
    }
    else {
        printf("Successfully saved to PKCS12 format.\n");
    }



    CkJavaKeyStore_Dispose(jks);
    CkPfx_Dispose(pkcs12);

    }