(C) Encrypt/Decrypt using PFX to produce -----BEGIN PKCS7----- ... -----END PKCS7-----

First we encrypt using a certificate + public key to produce output such as:

-----BEGIN PKCS7-----
MIIHPwYJKoZIhvcNAQcEoIIHMDCCBywC ...
...
...
-----END PKCS7-----

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

void ChilkatSample(void)
    {
    HCkCrypt2 crypt;
    HCkCert cert;
    BOOL success;
    const char *toBeEncrypted;
    const char *encryptedStr;
    HCkStringBuilder sb;
    const char *outStr;
    BOOL bCrlf;
    HCkCrypt2 decrypt;
    const char *decryptedText;

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

    crypt = CkCrypt2_Create();

    // Specify the encryption to be used.
    // "pki" indicates "Public Key Infrastructure" and will create a PKCS7 encrypted (enveloped) message.
    CkCrypt2_putCryptAlgorithm(crypt,"pki");
    CkCrypt2_putPkcs7CryptAlg(crypt,"aes");
    CkCrypt2_putKeyLength(crypt,128);
    CkCrypt2_putOaepHash(crypt,"sha256");
    CkCrypt2_putOaepPadding(crypt,TRUE);

    // A certificate is needed as the encryption key.
    // Althought the PFX contains the associated private key, we don't need it for encryption.
    // (A certificate usually contains the public key by default.)
    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 object to use the certificate.
    CkCrypt2_SetEncryptCert(crypt,cert);

    toBeEncrypted = "This string is to be encrypted.";

    // Get the result in multi-line BASE64 MIME format.
    CkCrypt2_putEncodingMode(crypt,"base64_mime");

    encryptedStr = CkCrypt2_encryptStringENC(crypt,toBeEncrypted);
    if (success != TRUE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkCrypt2_Dispose(crypt);
        CkCert_Dispose(cert);
        return;
    }

    // Make a "-----BEGIN PKCS7-----" ... "-----END PKCS7-----" sandwich...
    sb = CkStringBuilder_Create();
    CkStringBuilder_AppendLine(sb,"-----BEGIN PKCS7-----",TRUE);
    CkStringBuilder_Append(sb,encryptedStr);
    CkStringBuilder_AppendLine(sb,"-----END PKCS7-----",TRUE);

    outStr = CkStringBuilder_getAsString(sb);

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

    // Sample output:

    // -----BEGIN PKCS7-----
    // MIICXAYJKoZIhvcNAQcDoIICTTCCAkkCAQAxggH0MIIB8AIBADCBrDCBlzELMAkGA1UEBhMCR0Ix
    // GzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgGA1UEChMR
    // Q09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0EgQ2xpZW50IEF1dGhlbnRpY2F0
    // aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0ECEB6M1ZwZdZU7LrAIdurulmUwOAYJKoZIhvcNAQEHMCug
    // DzANBglghkgBZQMEAgEFAKEYMBYGCSqGSIb3DQEBCDAJBgUrDgMCGgUABIIBAK/BZG/iXJ8az7zL
    // 8EQ77mc+oDPQ4w1hyytK2ip4djkPVvTfYhcoDQ+G/DBU+urJfrVBi5H9gmpXwYyfKlyUxBVRVEJl
    // V/V5QQi4JmNTFbmgWh5tp9zDS98l6A2Va4Zs0Wy/owGLfvwitlxd1dsfVAV2hmBYS24BMpNcty5/
    // 0atcKYmSou13G78ztTKdMy1tECgZy8kerMsPdDQbSxEZkT3KpQ8C5uEQqYF3bIVaeZzha/Ywieh/
    // tvO0T4aAmeJufwkNdVECmU7kuhnNaVPXknFl7jeibTl6zA/VcJKBKcIYT9FRC7KjdooI8q+jtQ/V
    // k6RP4POaowkFg1QWRPEWeqIwTAYJKoZIhvcNAQcBMB0GCWCGSAFlAwQBAgQQEEFQduqeJqXQXzy4
    // JpkoDoAgdldJDB9zEkpMpgr5/fR2iLvh5kC6BPfhOYjsawBY4Ok=
    // -----END PKCS7-----

    // ----------------------------------------------------------------------------------------
    // Let's Decrypt the above string.

    // Start with what was produced above..
    CkStringBuilder_Clear(sb);
    bCrlf = TRUE;
    CkStringBuilder_AppendLine(sb,"-----BEGIN PKCS7-----",bCrlf);
    CkStringBuilder_AppendLine(sb,"MIICXAYJKoZIhvcNAQcDoIICTTCCAkkCAQAxggH0MIIB8AIBADCBrDCBlzELMAkGA1UEBhMCR0Ix",bCrlf);
    CkStringBuilder_AppendLine(sb,"GzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgGA1UEChMR",bCrlf);
    CkStringBuilder_AppendLine(sb,"Q09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0EgQ2xpZW50IEF1dGhlbnRpY2F0",bCrlf);
    CkStringBuilder_AppendLine(sb,"aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0ECEB6M1ZwZdZU7LrAIdurulmUwOAYJKoZIhvcNAQEHMCug",bCrlf);
    CkStringBuilder_AppendLine(sb,"DzANBglghkgBZQMEAgEFAKEYMBYGCSqGSIb3DQEBCDAJBgUrDgMCGgUABIIBAK/BZG/iXJ8az7zL",bCrlf);
    CkStringBuilder_AppendLine(sb,"8EQ77mc+oDPQ4w1hyytK2ip4djkPVvTfYhcoDQ+G/DBU+urJfrVBi5H9gmpXwYyfKlyUxBVRVEJl",bCrlf);
    CkStringBuilder_AppendLine(sb,"V/V5QQi4JmNTFbmgWh5tp9zDS98l6A2Va4Zs0Wy/owGLfvwitlxd1dsfVAV2hmBYS24BMpNcty5/",bCrlf);
    CkStringBuilder_AppendLine(sb,"0atcKYmSou13G78ztTKdMy1tECgZy8kerMsPdDQbSxEZkT3KpQ8C5uEQqYF3bIVaeZzha/Ywieh/",bCrlf);
    CkStringBuilder_AppendLine(sb,"tvO0T4aAmeJufwkNdVECmU7kuhnNaVPXknFl7jeibTl6zA/VcJKBKcIYT9FRC7KjdooI8q+jtQ/V",bCrlf);
    CkStringBuilder_AppendLine(sb,"k6RP4POaowkFg1QWRPEWeqIwTAYJKoZIhvcNAQcBMB0GCWCGSAFlAwQBAgQQEEFQduqeJqXQXzy4",bCrlf);
    CkStringBuilder_AppendLine(sb,"JpkoDoAgdldJDB9zEkpMpgr5/fR2iLvh5kC6BPfhOYjsawBY4Ok=",bCrlf);
    CkStringBuilder_AppendLine(sb,"-----END PKCS7-----",bCrlf);

    decrypt = CkCrypt2_Create();
    CkCrypt2_putCryptAlgorithm(decrypt,"pki");

    // Use the same cert + private key from the PFX above.
    // For decryption, we need the private key.  Given that the certificate was loaded from a PFX,
    // we should already have it.
    success = CkCrypt2_SetDecryptCert(decrypt,cert);

    CkCrypt2_putEncodingMode(decrypt,"base64");
    decryptedText = CkCrypt2_decryptStringENC(decrypt,CkStringBuilder_getBetween(sb,"-----BEGIN PKCS7-----","-----END PKCS7-----"));

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


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

    }