I need to have a Win32 application load a hard coded AES-256 key, ideally using the WinCrypt.h methods. I've got my key in an unsigned char[32] but I can't find the correct format of a key blob to pass to CryptImportKey. Everything seems to give me invalid parameter errors. Is there any way to do this?
(Also important is how to set IV in WinCrypt. I can't see how to do that at all)
Solved it. I was using the wrong bType and using 256 for keySize instead of 32.
BYTE myPrivateKey[] =
{1,2,3,4,5,6,7,8,9,10,
11,12,13,14,15,16,17,18,19,20,
21,22,23,24,25,26,27,28,29,30,
31,32};
BYTE myIV[] =
{1,2,3,4,5,6,7,8,9,10,
11,12,13,14,15,16};
struct aes256keyBlob
{
BLOBHEADER hdr;
DWORD keySize;
BYTE bytes[32];
} blob;
blob.hdr.bType = PLAINTEXTKEYBLOB;
blob.hdr.bVersion = CUR_BLOB_VERSION;
blob.hdr.reserved = 0;
blob.hdr.aiKeyAlg = CALG_AES_256;
blob.keySize = 32;
memcpy(blob.bytes, myPrivateKey, 32);
HCRYPTKEY hKey;
if (CryptImportKey(hCryptProv, (BYTE*)&blob, sizeof(aes256keyBlob), NULL, 0, &hKey))
{
if(CryptSetKeyParam(hKey, KP_IV, myIV, 0))
{
//do decryption here
}
else{/*error*/}
CryptDestroyKey(hKey);
}
else{/*error*/}