Unicode C

Save a Private Key as an Encrypted PKCS #8 DER File

Demonstrates the Chilkat PrivateKey.SavePkcs8EncryptedFile method, which saves the key as password-protected PKCS #8 DER. The first argument is the password and the second is the destination path. The cipher is selected by Pkcs8EncryptAlg.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: This is the recommended way to persist a key to disk: the binary .der is encrypted under a passphrase, so a stolen file is useless without it. Reach for it whenever a key is stored or shipped. Choose the encryption cipher with Pkcs8EncryptAlg and source the password securely.

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Unicode C

#include <C_CkPrivateKeyW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkPrivateKeyW privKey;
    const wchar_t *password;

    success = FALSE;

    //  Load a private key to export.
    privKey = CkPrivateKeyW_Create();
    success = CkPrivateKeyW_LoadPemFile(privKey,L"qa_data/private.pem");
    if (success == FALSE) {
        wprintf(L"%s\n",CkPrivateKeyW_lastErrorText(privKey));
        CkPrivateKeyW_Dispose(privKey);
        return;
    }

    //  The key password is not hard-coded in a real application; obtain it from an interactive
    //  prompt, environment variable, or a secrets vault.
    password = L"myKeyPassword";

    //  Save as password-protected PKCS #8 DER.  The 1st argument is the password and the 2nd is the
    //  destination path.  The cipher is selected by the Pkcs8EncryptAlg property.
    success = CkPrivateKeyW_SavePkcs8EncryptedFile(privKey,password,L"qa_output/private_pkcs8_enc.der");
    if (success == FALSE) {
        wprintf(L"%s\n",CkPrivateKeyW_lastErrorText(privKey));
        CkPrivateKeyW_Dispose(privKey);
        return;
    }

    wprintf(L"Saved (encrypted).\n");


    CkPrivateKeyW_Dispose(privKey);

    }