
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF
// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
// PARTICULAR PURPOSE.
//
// Copyright (C) Microsoft. All rights reserved.
/*++

Abstract:
    Sample program for AES-CBC encryption using CNG

--*/

#include <windows.h>
#include <stdio.h>
#include <bcrypt.h>
#include "common.h"

#pragma comment(lib, "Bcrypt.lib")

#define NT_SUCCESS(Status)          (((NTSTATUS)(Status)) >= 0)

#define STATUS_UNSUCCESSFUL         ((NTSTATUS)0xC0000001L)


#define DATA_TO_ENCRYPT  "Test Data"


const BYTE rgbPlaintext[] = 
{
    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 
    0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F
};

static const BYTE rgbIV[] =
{
    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
    0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F
};

static const BYTE rgbAES128Key[] =
{
    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 
    0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F
};

void PrintBytes(
                IN BYTE     *pbPrintData,
                IN DWORD    cbDataLen)
{
    DWORD dwCount = 0;

    for(dwCount=0; dwCount < cbDataLen;dwCount++)
    {
        printf("0x%02x, ",pbPrintData[dwCount]);

        if(0 == (dwCount + 1 )%10) putchar('\n');
    }

}

void CryptoExample()
{

    BCRYPT_ALG_HANDLE       hAesAlg                     = NULL;
    BCRYPT_KEY_HANDLE       hKey                        = NULL;
    NTSTATUS                status                      = STATUS_UNSUCCESSFUL;
    DWORD                   cbCipherText                = 0, 
                            cbPlainText                 = 0,
                            cbData                      = 0, 
                            cbKeyObject                 = 0,
                            cbBlockLen                  = 0,
                            cbBlob                      = 0;
    PBYTE                   pbCipherText                = NULL,
                            pbPlainText                 = NULL,
                            pbKeyObject                 = NULL,
                            pbIV                        = NULL,
                            pbBlob                      = NULL;    


    // Open an algorithm handle.
    if(!NT_SUCCESS(status = BCryptOpenAlgorithmProvider(
                                                &hAesAlg,
                                                BCRYPT_AES_ALGORITHM,
                                                NULL,
                                                0)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptOpenAlgorithmProvider\n", status);
        goto Cleanup;
    }

    // Calculate the size of the buffer to hold the KeyObject.
    if(!NT_SUCCESS(status = BCryptGetProperty(
                                        hAesAlg, 
                                        BCRYPT_OBJECT_LENGTH, 
                                        (PBYTE)&cbKeyObject, 
                                        sizeof(DWORD), 
                                        &cbData, 
                                        0)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptGetProperty\n", status);
        goto Cleanup;
    }

    // Allocate the key object on the heap.
    pbKeyObject = (PBYTE)HeapAlloc (GetProcessHeap (), 0, cbKeyObject);
    if(NULL == pbKeyObject)
    {
        wprintf(L"**** memory allocation failed\n");
        goto Cleanup;
    }

   // Calculate the block length for the IV.
    if(!NT_SUCCESS(status = BCryptGetProperty(
                                        hAesAlg, 
                                        BCRYPT_BLOCK_LENGTH, 
                                        (PBYTE)&cbBlockLen, 
                                        sizeof(DWORD), 
                                        &cbData, 
                                        0)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptGetProperty\n", status);
        goto Cleanup;
    }

    // Determine whether the cbBlockLen is not longer than the IV length.
    if (cbBlockLen > sizeof (rgbIV))
    {
        wprintf (L"**** block length is longer than the provided IV length\n");
        goto Cleanup;
    }

    // Allocate a buffer for the IV. The buffer is consumed during the 
    // encrypt/decrypt process.
    pbIV= (PBYTE) HeapAlloc (GetProcessHeap (), 0, cbBlockLen);
    if(NULL == pbIV)
    {
        wprintf(L"**** memory allocation failed\n");
        goto Cleanup;
    }

    memcpy(pbIV, rgbIV, cbBlockLen);

    if(!NT_SUCCESS(status = BCryptSetProperty(
                                hAesAlg, 
                                BCRYPT_CHAINING_MODE, 
                                (PBYTE)BCRYPT_CHAIN_MODE_CBC, 
                                sizeof(BCRYPT_CHAIN_MODE_CBC), 
                                0)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptSetProperty\n", status);
        goto Cleanup;
    }

                

     // Generate the key from supplied input key bytes.
    if(!NT_SUCCESS(status = BCryptGenerateSymmetricKey(
                                        hAesAlg, 
                                        &hKey, 
                                        pbKeyObject, 
                                        cbKeyObject, 
                                        (PBYTE)rgbAES128Key, 
                                        sizeof(rgbAES128Key), 
                                        0)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptGenerateSymmetricKey\n", status);
        goto Cleanup;
    }

  
    // Save another copy of the key for later.
    if(!NT_SUCCESS(status = BCryptExportKey(
                                        hKey,
                                        NULL,
                                        BCRYPT_OPAQUE_KEY_BLOB,
                                        NULL,
                                        0,
                                        &cbBlob,
                                        0)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptExportKey\n", status);
        goto Cleanup;
    }


    // Allocate the buffer to hold the BLOB.
    pbBlob = (PBYTE)HeapAlloc (GetProcessHeap (), 0, cbBlob);
    if(NULL == pbBlob)
    {
        wprintf(L"**** memory allocation failed\n");
        goto Cleanup;
    }

    if(!NT_SUCCESS(status = BCryptExportKey(
                                        hKey, 
                                        NULL, 
                                        BCRYPT_OPAQUE_KEY_BLOB,
                                        pbBlob, 
                                        cbBlob, 
                                        &cbBlob, 
                                        0)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptExportKey\n", status);
        goto Cleanup;
    }
 
    cbPlainText = sizeof(rgbPlaintext);
    pbPlainText = (PBYTE)HeapAlloc (GetProcessHeap (), 0, cbPlainText);
    if(NULL == pbPlainText)
    {
        wprintf(L"**** memory allocation failed\n");
        goto Cleanup;
    }

    memcpy(pbPlainText, rgbPlaintext, sizeof(rgbPlaintext));
    
    //
    // Get the output buffer size.
    //
    if(!NT_SUCCESS(status = BCryptEncrypt(
                                        hKey, 
                                        pbPlainText, 
                                        cbPlainText,
                                        NULL,
                                        pbIV,
                                        cbBlockLen,
                                        NULL, 
                                        0, 
                                        &cbCipherText, 
                                        BCRYPT_BLOCK_PADDING)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptEncrypt\n", status);
        goto Cleanup;
    }

    pbCipherText = (PBYTE)HeapAlloc (GetProcessHeap (), 0, cbCipherText);
    if(NULL == pbCipherText)
    {
        wprintf(L"**** memory allocation failed\n");
        goto Cleanup;
    }

    // Use the key to encrypt the plaintext buffer.
    // For block sized messages, block padding will add an extra block.
    if(!NT_SUCCESS(status = BCryptEncrypt(
                                        hKey, 
                                        pbPlainText, 
                                        cbPlainText,
                                        NULL,
                                        pbIV,
                                        cbBlockLen, 
                                        pbCipherText, 
                                        cbCipherText, 
                                        &cbData, 
                                        BCRYPT_BLOCK_PADDING)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptEncrypt\n", status);
        goto Cleanup;
    }

    // Destroy the key and reimport from saved BLOB.
    if(!NT_SUCCESS(status = BCryptDestroyKey(hKey)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptDestroyKey\n", status);
        goto Cleanup;
    }    
    hKey = 0;

    if(pbPlainText)
    {
        HeapFree(GetProcessHeap(), 0, pbPlainText);
    }

    pbPlainText = NULL;

    // We can reuse the key object.
    memset(pbKeyObject, 0 , cbKeyObject);

    
    // Reinitialize the IV because encryption would have modified it.
    memcpy(pbIV, rgbIV, cbBlockLen);

#if 0
    if(!NT_SUCCESS(status = BCryptImportKey(
                                        hAesAlg,
                                        NULL,
                                        BCRYPT_OPAQUE_KEY_BLOB,
                                        &hKey,
                                        pbKeyObject,
                                        cbKeyObject,
                                        pbBlob,
                                        cbBlob,
                                        0)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptGenerateSymmetricKey\n", status);
        goto Cleanup;
    }
#else
    BCryptCloseAlgorithmProvider(hAesAlg,0);

    if(!NT_SUCCESS(status = BCryptOpenAlgorithmProvider(
                                                &hAesAlg,
                                                BCRYPT_AES_ALGORITHM,
                                                NULL,
                                                0)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptOpenAlgorithmProvider\n", status);
        goto Cleanup;
    }

     // Generate the key from supplied input key bytes.
    if(!NT_SUCCESS(status = BCryptGenerateSymmetricKey(
                                        hAesAlg, 
                                        &hKey, 
                                        pbKeyObject, 
                                        cbKeyObject, 
                                        (PBYTE)rgbAES128Key, 
                                        sizeof(rgbAES128Key), 
                                        0)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptGenerateSymmetricKey\n", status);
        goto Cleanup;
    }
#endif  

    //
    // Get the output buffer size.
    //
    if(!NT_SUCCESS(status = BCryptDecrypt(
                                    hKey, 
                                    pbCipherText, 
                                    cbCipherText, 
                                    NULL,
                                    pbIV,
                                    cbBlockLen,
                                    NULL, 
                                    0, 
                                    &cbPlainText, 
                                    BCRYPT_BLOCK_PADDING)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptDecrypt\n", status);
        goto Cleanup;
    }

    pbPlainText = (PBYTE)HeapAlloc (GetProcessHeap (), 0, cbPlainText);
    if(NULL == pbPlainText)
    {
        wprintf(L"**** memory allocation failed\n");
        goto Cleanup;
    }

    if(!NT_SUCCESS(status = BCryptDecrypt(
                                    hKey, 
                                    pbCipherText, 
                                    cbCipherText, 
                                    NULL,
                                    pbIV, 
                                    cbBlockLen,
                                    pbPlainText, 
                                    cbPlainText, 
                                    &cbPlainText, 
                                    BCRYPT_BLOCK_PADDING)))
    {
        wprintf(L"**** Error 0x%x returned by BCryptDecrypt\n", status);
        goto Cleanup;
    }


    if (0 != memcmp(pbPlainText, (PBYTE)rgbPlaintext, sizeof(rgbPlaintext))) 
    {
        wprintf(L"Expected decrypted text comparison failed.\n");
        goto Cleanup;
    } 

    wprintf(L"Success!\n");


Cleanup:

    if(hAesAlg)
    {
        BCryptCloseAlgorithmProvider(hAesAlg,0);
    }

    if (hKey)    
    {
        BCryptDestroyKey(hKey);
    }

    if(pbCipherText)
    {
        HeapFree(GetProcessHeap(), 0, pbCipherText);
    }

    if(pbPlainText)
    {
        HeapFree(GetProcessHeap(), 0, pbPlainText);
    }

    if(pbKeyObject)
    {
        HeapFree(GetProcessHeap(), 0, pbKeyObject);
    }

    if(pbIV)
    {
        HeapFree(GetProcessHeap(), 0, pbIV);
    }

}