(C) Sign JSON (or any Text) to Create a Detached PKCS7 Signature

Demonstrates how to sign JSON or any string using a certificate + private key from a .p12/.pfx to create a detached PKCS7 signature. (A detached signature is one that does not embed the original signed data.)

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#include <C_CkCrypt2.h>
#include <C_CkCert.h>
#include <C_CkByteData.h>

void ChilkatSample(void)
    {
    HCkCrypt2 crypt;
    HCkCert cert;
    BOOL success;
    HCkByteData detachedSig;
    const char *stringToSign;
    BOOL verified;

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

    crypt = CkCrypt2_Create();

    cert = CkCert_Create();
    success = CkCert_LoadPfxFile(cert,"qa_data/pfx/cert_test123.pfx","test123");
    if (success != TRUE) {
        printf("%s\n",CkCert_lastErrorText(cert));
        CkCrypt2_Dispose(crypt);
        CkCert_Dispose(cert);
        return;
    }

    // Tell the crypt component to use this cert.
    success = CkCrypt2_SetSigningCert(crypt,cert);
    if (success != TRUE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkCrypt2_Dispose(crypt);
        CkCert_Dispose(cert);
        return;
    }

    CkCrypt2_putHashAlgorithm(crypt,"sha256");

    // By default, all the certs in the chain of authentication are included in the signature.
    // If desired, we can choose to only include the signing certificate:
    CkCrypt2_putIncludeCertChain(crypt,FALSE);

    // Create the detached signature, which does NOT contain the original data.
    // To create a PKCS7 signature that contains the original data, see CAdES Sign JSON
    CkCrypt2_putCharset(crypt,"utf-8");
    detachedSig = CkByteData_Create();
    stringToSign = "{ \"abc\": 123}";
    success = CkCrypt2_SignString(crypt,stringToSign,detachedSig);
    if (CkCrypt2_getLastMethodSuccess(crypt) == FALSE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkCrypt2_Dispose(crypt);
        CkCert_Dispose(cert);
        CkByteData_Dispose(detachedSig);
        return;
    }

    // Verify the signature against the original data.
    verified = CkCrypt2_VerifyString(crypt,stringToSign,detachedSig);
    if (verified == FALSE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkCrypt2_Dispose(crypt);
        CkCert_Dispose(cert);
        CkByteData_Dispose(detachedSig);
        return;
    }

    printf("Success!\n");


    CkCrypt2_Dispose(crypt);
    CkCert_Dispose(cert);
    CkByteData_Dispose(detachedSig);

    }