Unicode C++

Export a Public Key as PEM

Demonstrates the Chilkat PublicKey.GetPem method, which returns the public key in PEM format. The only argument selects the underlying DER representation: true prefers the traditional PKCS #1 form (RSA), false uses the SubjectPublicKeyInfo form.

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: PEM is the most portable way to share a public key — the Base64 text block most tooling reads. The boolean picks the encoding: false produces the modern, algorithm-independent PUBLIC KEY (SubjectPublicKeyInfo), which is the usual choice; true produces the older RSA-specific RSA PUBLIC KEY for tools that require it. A public key is not sensitive, so the PEM can be distributed openly.

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#include <CkPublicKeyW.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  Load a public key to export.  LoadFromFile inspects the content, so it accepts DER, PEM, XML,
    //  JWK, and other supported representations.
    CkPublicKeyW pubKey;
    success = pubKey.LoadFromFile(L"qa_data/public.pem");
    if (success == false) {
        wprintf(L"%s\n",pubKey.lastErrorText());
        return;
    }

    //  Export the public key in PEM format.  The argument selects the underlying DER representation:
    //  true prefers the traditional PKCS #1 form (RSA), false uses the SubjectPublicKeyInfo form.
    bool preferPkcs1 = false;
    const wchar_t *pem = pubKey.getPem(preferPkcs1);
    if (pubKey.get_LastMethodSuccess() == false) {
        wprintf(L"%s\n",pubKey.lastErrorText());
        return;
    }

    wprintf(L"%s\n",pem);
    }