Export a Public Key as DER into a BinData

Demonstrates the Chilkat PublicKey.GetDerBd method, which writes the public key as binary DER into a BinData. The first argument selects the representation (as for GetPem) and the second is the BinData that receives the bytes (its contents are replaced).

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: The in-memory binary export: the raw DER lands in a BinData ready to hash, transmit, or hand to another API without a temporary file. It is the BinData counterpart to the text exporters, and the first argument picks the same PKCS #1 versus SubjectPublicKeyInfo structure.

Chilkat C Downloads

Download Chilkat for C

#include <C_CkPublicKey.h>
#include <C_CkBinData.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkPublicKey pubKey;
    BOOL preferPkcs1;
    HCkBinData bd;

    success = FALSE;

    //  Load a public key to export.  LoadFromFile inspects the content, so it accepts DER, PEM, XML,
    //  JWK, and other supported representations.
    pubKey = CkPublicKey_Create();
    success = CkPublicKey_LoadFromFile(pubKey,"qa_data/public.pem");
    if (success == FALSE) {
        printf("%s\n",CkPublicKey_lastErrorText(pubKey));
        CkPublicKey_Dispose(pubKey);
        return;
    }

    //  Write the public key as binary DER into a BinData.  The 1st argument selects the representation
    //  (as for GetPem) and the 2nd is the BinData that receives the bytes (its contents are replaced).
    preferPkcs1 = FALSE;
    bd = CkBinData_Create();
    success = CkPublicKey_GetDerBd(pubKey,preferPkcs1,bd);
    if (success == FALSE) {
        printf("%s\n",CkPublicKey_lastErrorText(pubKey));
        CkPublicKey_Dispose(pubKey);
        CkBinData_Dispose(bd);
        return;
    }

    printf("Exported %d DER bytes.\n",CkBinData_getNumBytes(bd));


    CkPublicKey_Dispose(pubKey);
    CkBinData_Dispose(bd);

    }