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 * modification, are permitted provided that the following conditions
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 *
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 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
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 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// Enclave2.cpp : Defines the exported functions for the DLL application
#include "sgx_eid.h"
#include "EnclaveResponder_t.h"
#include "EnclaveMessageExchange.h"
#include "error_codes.h"
#include "Utility_E2.h"
#include "sgx_dh.h"
#include "sgx_utils.h"
#include <map>

#define UNUSED(val) (void)(val)

std::map<sgx_enclave_id_t, dh_session_t>g_src_session_info_map;

// this is expected initiator's MRSIGNER for demonstration purpose
//Please replace with your project responder enclave's MRSIGNER in your project!!!
//The command to get your signed enclave's MRSIGNER: <SGX_SDK Installation Path>/bin/x64/sgx_sign dump -enclave <Signed Enclave> -dumpfile mrsigner.txt
//Find the signed enclave's MRSIGNER in the mrsigner.txt<mrsigner->value:>, then replace blow value
sgx_measurement_t g_initiator_mrsigner = {
    {
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff    
    }
};

/* Function Description:
 *   this is to verify peer enclave's identity
 * For demonstration purpose, we verify below points:
 *   1. peer enclave's MRSIGNER is as expected
 *   2. peer enclave's PROD_ID is as expected
 *   3. peer enclave's attribute is reasonable that it should be INITIALIZED and without DEBUG attribute (except the project is built with DEBUG option)
 * */
extern "C" uint32_t verify_peer_enclave_trust(sgx_dh_session_enclave_identity_t* peer_enclave_identity)
{
    if(!peer_enclave_identity)
        return INVALID_PARAMETER_ERROR;

    // check peer enclave's MRSIGNER
    // Please enable blow check in your project!!!
    /*
    if (memcmp((uint8_t *)&peer_enclave_identity->mr_signer, (uint8_t*)&g_initiator_mrsigner, sizeof(sgx_measurement_t)))
        return ENCLAVE_TRUST_ERROR;
    */
    if(peer_enclave_identity->isv_prod_id != 0 || !(peer_enclave_identity->attributes.flags & SGX_FLAGS_INITTED))
        return ENCLAVE_TRUST_ERROR;

    // check the enclave isn't loaded in enclave debug mode, except that the project is built for debug purpose
#if defined(NDEBUG)
    if (peer_enclave_identity->attributes.flags & SGX_FLAGS_DEBUG)
        return ENCLAVE_TRUST_ERROR;
#endif

    return SUCCESS;
}

/* Function Description: Operates on the input secret and generates the output secret */
uint32_t get_message_exchange_response(uint32_t inp_secret_data)
{
    uint32_t secret_response;

    //User should use more complex encryption method to protect their secret, below is just a simple example
    secret_response = inp_secret_data & 0x11111111;

    return secret_response;

}

/* Function Description: Generates the response from the request message
 * Parameter Description:
 * [input] decrtyped_data: pointer to decrypted data
 * [output] resp_buffer: pointer to response message, which is allocated in this function
 * [output] resp_length: this is response length */
extern "C" uint32_t message_exchange_response_generator(char* decrypted_data,
                                              char** resp_buffer,
                                               size_t* resp_length)
{
    ms_in_msg_exchange_t *ms;
    uint32_t inp_secret_data;
    uint32_t out_secret_data;

    if(!decrypted_data || !resp_length)
        return INVALID_PARAMETER_ERROR;

    ms = (ms_in_msg_exchange_t *)decrypted_data;

    if(umarshal_message_exchange_request(&inp_secret_data,ms) != SUCCESS)
        return ATTESTATION_ERROR;

    out_secret_data = get_message_exchange_response(inp_secret_data);

    if(marshal_message_exchange_response(resp_buffer, resp_length, out_secret_data) != SUCCESS)
        return MALLOC_ERROR;

    return SUCCESS;
}