C

Sign a Byte Array to Create a Detached Signature in a Byte Array

See more Digital Signatures Examples

Signs data contained in a byte array to produce a detached signature (also in a byte array). Also shows how to verify the signature. C

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

void ChilkatSample(void)
    {
    BOOL success;
    HCkCert cert;
    HCkFileAccess fac;
    HCkByteData fileBytes;
    HCkCrypt2 crypt;
    HCkByteData sigBytes;
    BOOL verified;

    success = FALSE;

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

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

    fac = CkFileAccess_Create();

    fileBytes = CkByteData_Create();
    success = CkFileAccess_ReadEntireFile(fac,"qa_data/pdf/sample.pdf",fileBytes);
    if (CkFileAccess_getLastMethodSuccess(fac) != TRUE) {
        printf("%s\n",CkFileAccess_lastErrorText(fac));
        CkCert_Dispose(cert);
        CkFileAccess_Dispose(fac);
        CkByteData_Dispose(fileBytes);
        return;
    }

    crypt = CkCrypt2_Create();

    success = CkCrypt2_SetSigningCert(crypt,cert);

    //  We can sign any type of file.
    //  The result is a detached signature (a signature that does not contain the data being signed).

    sigBytes = CkByteData_Create();
    success = CkCrypt2_SignBytes(crypt,fileBytes,sigBytes);
    if (CkCrypt2_getLastMethodSuccess(crypt) != TRUE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkCert_Dispose(cert);
        CkFileAccess_Dispose(fac);
        CkByteData_Dispose(fileBytes);
        CkCrypt2_Dispose(crypt);
        CkByteData_Dispose(sigBytes);
        return;
    }

    success = CkFileAccess_WriteEntireFile(fac,"qa_output/sample.pdf.p7s",sigBytes);
    if (CkFileAccess_getLastMethodSuccess(fac) != TRUE) {
        printf("%s\n",CkFileAccess_lastErrorText(fac));
        CkCert_Dispose(cert);
        CkFileAccess_Dispose(fac);
        CkByteData_Dispose(fileBytes);
        CkCrypt2_Dispose(crypt);
        CkByteData_Dispose(sigBytes);
        return;
    }

    //  We can verify the detached signature like this
    verified = CkCrypt2_VerifyBytes(crypt,fileBytes,sigBytes);
    if (CkCrypt2_getLastMethodSuccess(crypt) != TRUE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkCert_Dispose(cert);
        CkFileAccess_Dispose(fac);
        CkByteData_Dispose(fileBytes);
        CkCrypt2_Dispose(crypt);
        CkByteData_Dispose(sigBytes);
        return;
    }

    printf("Verified = %d\n",verified);


    CkCert_Dispose(cert);
    CkFileAccess_Dispose(fac);
    CkByteData_Dispose(fileBytes);
    CkCrypt2_Dispose(crypt);
    CkByteData_Dispose(sigBytes);

    }