[Assignment-7] add first enclave part

Assignment 7 - SGX Hands-on/src/enclave/enclave.c

@@ -0,0 +1,28 @@
+#include "Enclave.h"
+#include "Enclave_t.h"
+#include <sgx_error.h>
+#include <sgx_tcrypto.h>
+
+sgx_status_t public_key(uint8_t *gx, uint8_t *gy) {
+    // unseal key or from file system
+}
+
+sgx_status_t sign_firmware(uint8_t *data, size_t data_size, uint8_t *signature, size_t signature_size) {
+    sgx_ecc_state_handle_t ecc_handle;
+    sgx_ec256_private_t private;
+    sgx_ec256_public_t public;
+
+    sgx_status_t status;
+    if((status = sgx_ecc256_open_context(&ecc_handle)) != SGX_SUCCESS)
+        return status;
+    
+    if((status = sgx_ecc256_create_key_pair(&private, &public, ecc_handle)) != SGX_SUCCESS)
+        return status;
+    
+    sgx_ec256_signature_t ecc_signature;
+    if((status = sgx_ecdsa_sign(data, data_size, &private, &ecc_signature, ecc_handle)) != SGX_SUCCESS)
+        return status;
+    
+    sgx_ecc256_close_context(ecc_handle);
+    return SGX_SUCCESS;
+}