How do I import a public key for encryption in C on Windows

Question

I have a public key and I want to use it to encrypt a piece of data. I'm trying to import the public key in order to use it, but CryptImportKey gives me an 'invalic parameter' error.

What's the problem?

Here's my code:

if( !CryptAcquireContext(&hProv, NULL, NULL, PROV_RSA_AES, CRYPT_VERIFYCONTEXT) )
{
    /*
     * Print error and return
     */
}
pblob->header->bType = PUBLICKEYBLOB;
pblob->header->aiKeyAlg = CALG_AES_128;
pblob->header->bVersion = CUR_BLOB_VERSION;
pblob->header->reserved = 0;
pblob->key_len = key_len;

memcpy(pblob->key, key , key_len);

if( !CryptImportKey( &hProv,
    (LPCBYTE)pblob,
    sizeof(*pblob),
    0,
    CRYPT_EXPORTABLE,
    &hKey ) )
{
    // Print error and return
}

Answer 1

Windows CryptoAPI doesn't work directly with plain text keys; you have to jump through a bit of a hoop to do this. Here is the knowledge base article describing how to do this.

Answer 2

Thanks to all that was said here, and a lot of searching, I found the answer in: http://www.ms-news.net/f2748/problem-importing-public-key-4052577.html

And used it to create my own program which I posted on the other thread at: http://stackoverflow.com/questions/1231178/load-an-x509-pem-file-into-windows-cryptoapi/3803333#3803333