(MFC) Load Signed and/or Encrypted Email and Unwrap Security Layers

The LoadEml method loads an email (.eml file containing the MIME of an email) and automatically unwraps the digital signature and encryption security layers. A program can then examine the properties of the email object to see what was unwrapped.

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

See Also: Using MFC CString in Chilkat

#include <CkEmail.h>

void ChilkatSample(void)
    {
    CkString strOut;

    CkEmail email;

    //  Provide PFX/.p12 files for any certs+keys needed for decryption.
    //  Signature verification does not need anything extra.
    //  (Also, Chilkat will automatically find and use pre-installed certs + private keys needed for decryption
    //  on a Windows system.)
    bool success = email.AddPfxSourceFile("/pfxFiles/certs_and_keys_1.pfx","pfxPassword1");
    if (success != true) {
        strOut.append(email.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    success = email.AddPfxSourceFile("/pfxFiles/certs_and_keys_2.pfx","pfxPassword2");
    if (success != true) {
        strOut.append(email.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    //  ...

    //  Load a potentially signed and/or encrypted email.
    success = email.LoadEml("someDir/someEmail.eml");

    //  If the email was signed and/or encrypted, it was "unwrapped", i.e.
    //  the email is already decrypted and in a state as if it were never signed or encrypted.

    //  You may check to see if the email was received encrypted or signed, and if so,
    //  whether it was successfully unwrapped and who signed or encrypted it:
    if (email.get_ReceivedEncrypted() == true) {

        strOut.append("This email was encrypted.");
        strOut.append("\r\n");
        if (email.get_Decrypted() == true) {
            strOut.append("This email was successfully decrypted.  It was encrypted by:");
            strOut.append("\r\n");
            strOut.append(email.encryptedBy());
            strOut.append("\r\n");
        }
        else {
            strOut.append("This email was not decrypted.");
            strOut.append("\r\n");
        }

    }

    if (email.get_ReceivedSigned() == true) {

        strOut.append("This email was signed.");
        strOut.append("\r\n");
        if (email.get_SignaturesValid() == true) {
            strOut.append("The signature was verified.  It was signed by:");
            strOut.append("\r\n");
            strOut.append(email.signedBy());
            strOut.append("\r\n");
        }
        else {
            strOut.append("The signature verification failed.");
            strOut.append("\r\n");
        }

    }

    //  At this point, the contents of the email, including attachments, can be accessed normally..


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }