如何使用CryptoAPI从p7b证书中提取公钥

$HCERTSTORE cert_store_handle = CertOpenStore(
    CERT_STORE_PROV_PKCS7,
    PKCS_7_ASN_ENCODING,
    NULL,
    CERT_STORE_OPEN_EXISTING_FLAG | CERT_STORE_READONLY_FLAG,
    &opm_data_blob
    );

CryptDecodeObject(X509_ASN_ENCODING | PKCS_7_ASN_ENCODING, RSA_CSP_PUBLICKEYBLOB, (BYTE*) pubkey + 46, pubkey_len - 46, CRYPT_DECODE_NO_SIGNATURE_BYTE_REVERSAL_FLAG, NULL, &pubkey_decoded_size);

{
    BOOL crypt_res = FALSE;

    HCRYPTPROV crypt_prov_hndl = NULL;
    crypt_res = CryptAcquireContext(&crypt_prov_hndl, NULL, NULL, PROV_RSA_FULL, 0/*CRYPT_NEWKEYSET*/);

    if (!crypt_res) {
        HRESULT decode_hr = __HRESULT_FROM_WIN32(GetLastError());
        return decode_hr;
    }

    HCRYPTKEY crypt_key_hndl = NULL;
    crypt_res = CryptImportPublicKeyInfoEx(crypt_prov_hndl, X509_ASN_ENCODING, signer_public_key, CALG_RSA_SIGN, 0, NULL, &crypt_key_hndl);

    if (!crypt_res) {
        HRESULT decode_hr = __HRESULT_FROM_WIN32(GetLastError());
        return decode_hr;
    }

    crypt_res = CryptReleaseContext(crypt_prov_hndl, 0);
}