C

Create PEM-encoded PKCS#7 Detached Signature

See more Digital Signatures Examples

Demonstrates how to create a PKCS7 PEM-encoded object containing a detached signature. C

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

void ChilkatSample(void)
    {
    BOOL success;
    HCkCert cert;
    HCkCrypt2 crypt;
    const char *textToSign;
    const char *sigBase64;
    HCkStringBuilder sb;
    BOOL crlf;

    success = FALSE;

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

    cert = CkCert_Create();

    // Load the cert and private key.
    success = CkCert_LoadPfxFile(cert,"qa_data/pfx/myCertAndKey.p12","password");
    if (success != TRUE) {
        printf("%s\n",CkCert_lastErrorText(cert));
        CkCert_Dispose(cert);
        return;
    }

    crypt = CkCrypt2_Create();

    success = CkCrypt2_SetSigningCert(crypt,cert);
    if (success != TRUE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkCert_Dispose(cert);
        CkCrypt2_Dispose(crypt);
        return;
    }

    // Use SHA-256
    CkCrypt2_putHashAlgorithm(crypt,"sha256");

    // Hash the utf-8 byte representation of the string
    CkCrypt2_putCharset(crypt,"utf-8");

    // Return the result in base64
    CkCrypt2_putEncodingMode(crypt,"base64Mime");

    // Sign some text to create a detached signature (i.e. a signature that does not include the signed data)
    textToSign = "This is the text to be hashed and signed.";
    sigBase64 = CkCrypt2_signStringENC(crypt,textToSign);
    if (CkCrypt2_getLastMethodSuccess(crypt) != TRUE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkCert_Dispose(cert);
        CkCrypt2_Dispose(crypt);
        return;
    }

    printf("%s\n",sigBase64);

    // The result:

    // MIIWbgYJKoZIhvcNAQcCoIIWXzCCFlsCAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg
    // ghMXMIIFuzCCA6OgAwIBAgIIVwoRl0LE48wwDQYJKoZIhvcNAQELBQAwazELMAkGA1UEBhMCSVQx
    // ...
    // ...

    // If we want it in PEM format with just LF line-endings:
    sb = CkStringBuilder_Create();
    // Just LF line endings, not CRLF.
    crlf = FALSE;
    CkStringBuilder_AppendLine(sb,"-----BEGIN PKCS7-----",crlf);
    CkStringBuilder_Append(sb,sigBase64);
    CkStringBuilder_AppendLine(sb,"-----END PKCS7-----",crlf);
    CkStringBuilder_ToLF(sb);

    // Save to a file.
    CkStringBuilder_WriteFile(sb,"c:/temp/qa_output/sig.pem","utf-8",FALSE);

    // Examine..
    printf("%s\n",CkStringBuilder_getAsString(sb));

    // Result is:

    // -----BEGIN PKCS7-----
    // MIIWbgYJKoZIhvcNAQcCoIIWXzCCFlsCAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg
    // ghMXMIIFuzCCA6OgAwIBAgIIVwoRl0LE48wwDQYJKoZIhvcNAQELBQAwazELMAkGA1UEBhMCSVQx
    // DjAMBgNVBAcMBU1pbGFuMSMwIQYDVQQKDBpBY3RhbGlzIFMucC5BLi8wMzM1ODUyMDk2NzEnMCUG
    // A1UEAwweQWN0YWxpcyBBdXRoZW50aWNhdGlvbiBSb290IENBMB4XDTExMDkyMjExMjIwMloXDTMw
    // MDkyMjExMjIwMlowazELMAkGA1UEBhMCSVQxDjAMBgNVBAcMBU1pbGFuMSMwIQYDVQQKDBpBY3Rh
    // bGlzIFMucC5BLi8wMzM1ODUyMDk2NzEnMCUGA1UEAwweQWN0YWxpcyBBdXRoZW50aWNhdGlvbiBS
    // b290IENBMIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEAp8bEpSmkLO/lGMWwUKNvUTuf
    // ClrJwkg4CsIcoBh/kbWHuUA/3R1oHwiD1S0eiKD4j1aPbZkCkpAW1V8IbInX4ay8IMKx4INRimlN
    // AJZaby/ARH6jDuSRzVju3PvHHkVH3Se5CAGfpiEd9UEtL0z9KK3giq0itFZljoZUj5NDKd45Rnij
    // MCO6zfB9E1fAXdKDa0hMxKufgFpbOr3JpyI/gCczWw63igxdBzcIy2zSekciRDXFzMwujt0q7bd9
    // ...
    // ...
    // -----END PKCS7-----


    CkCert_Dispose(cert);
    CkCrypt2_Dispose(crypt);
    CkStringBuilder_Dispose(sb);

    }