C / C++ / MFC

HCRYPTPROV hcp;
HCRYPTKEY hcc;
 
    if ( !CryptAcquireContext ( &hcp, NULL, MS_ENHANCED_PROV, PROV_RSA_FULL, 0 ) &&
         GetLastError() == NTE_BAD_KEYSET )
        {
        CryptAcquireContext ( &hcp, NULL, MS_ENHANCED_PROV, PROV_RSA_FULL, CRYPT_NEWKEYSET ) )
        }
 
    <font color=red>// This should generate a public/private key pair, right?</font>
    CryptGenKey ( hcp, CALG_RSA_KEYX, (4096<<16)|CRYPT_EXPORTABLE, &hcc );
 
DWORD cbyBlob = 0;
BYTE* pbyPublicBlob = NULL, *pbyPrivateBlob = NULL;
 
    CryptExportKey ( hcc, NULL, PUBLICKEYBLOB, 0, NULL, &cbyBlob );
 
    pbyPublicBlob = new BYTE[cbyBlob];
 
    CryptExportKey ( hcc, NULL, PUBLICKEYBLOB, 0, pbyPublicBlob, &cbyBlob );
    // OMITTED: Write pbyPublicBlob to a C struct.
 
    CryptExportKey ( hcc, NULL, PRIVATEKEYBLOB, 0, NULL, &cbyBlob );
 
    pbyPrivateBlob = new BYTE[cbyBlob];
 
    CryptExportKey ( hcc, NULL, PRIVATEKEYBLOB, 0, pbyPrivateBlob, &cbyBlob );
    // OMITTED: Write pbyPrivateBlob to a C struct.

BYTE abyPublicKey[] = { ... };
BYTE abyPrivateKey[] = { ... };

HCRYPTKEY hpubkey;
 
    // OMITTED: Same CryptAcquireContext() call as above
    CryptImportKey ( hcp, abyPublicKey, sizeof(abyPublicKey), NULL, 0, &hpubkey );
 
    // Encrypt some text
BYTE thetext[] = "The Code Project", *pbyBuffer = NULL;
DWORD cbyPlainText = sizeof(thetext), cbyCipherText = 0;
 
    CryptEncrypt ( hpubkey, NULL, TRUE, 0, NULL, &cbyCipherText, cbyPlainText );
 
    pbyBuffer = new BYTE[cbyCipherText];
    memcpy ( pbyBuffer, thetext, cbyPlainText );
 
    CryptEncrypt ( hpubkey, NULL, TRUE, 0, pbyBuffer, &cbyPlainText, cbyCipherText );
 
    // Decrypt it back
BYTE* pbyDecrypted = new BYTE[cbyCipherText];
 
    memcpy ( pbyDecrypted, pbyBuffer, cbyCipherText );
 
    <font color=red>// THIS WORKS:</font>
    CryptDecrypt ( hpubkey, NULL, TRUE, 0, pbyDecrypted, &cbyCipherText );