(MFC) Verify and Unwrap PCKS7 Signed MIME

Demonstrates calling the Verify method to verify and unwrap PKCS7 signed MIME. The MIME is restored to the original structure that it would have originally had prior to signing. The Verify method works with both detached signatures, as well as opaque/attached signatures.

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkMime.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    CkMime mime;

    // A PKCS7 signature usually embeds both the signing
    // certificate with its public key.  Therefore, it is usually 
    // possible to verify a signature without the need to 
    // already have the certificate installed.

    // Load the signed MIME from a file...
    bool success = mime.LoadMimeFile("signedMime.txt");
    if (success == false) {
        strOut.append(mime.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Verify the signed MIME and restore the MIME
    // to the structure/content it had prior to signing.
    bool verified;
    verified = mime.Verify();
    if (verified == false) {
        strOut.append(mime.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Examine the MIME after signature verification (i.e. "unwrapping")
    strOut.append(mime.getMime());
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }