diff --git a/7-SGX_Hands-on/src/enclave/enclave.c b/7-SGX_Hands-on/src/enclave/enclave.c
index 2c62e70..08cdee1 100644
--- a/7-SGX_Hands-on/src/enclave/enclave.c
+++ b/7-SGX_Hands-on/src/enclave/enclave.c
@@ -80,7 +80,7 @@ int get_private_key_size() {
     return SK_SIZE;
 }
 
-sgx_status_t seal_key_pair(sgx_ec256_private_t *private, sgx_ec256_public_t *public, uint8_t **sealed, uint32_t sealed_size) {
+static sgx_status_t seal_key_pair(sgx_ec256_private_t *private, sgx_ec256_public_t *public, uint8_t **sealed, uint32_t sealed_size) {
     // invalid parameter handling
     if((private == NULL) || (public == NULL))
         return SGX_ERROR_INVALID_PARAMETER;
@@ -103,7 +103,7 @@ sgx_status_t seal_key_pair(sgx_ec256_private_t *private, sgx_ec256_public_t *pub
     return sgx_seal_data(PK_SIZE, (const uint8_t *)pk, SK_SIZE, (const uint8_t *)sk, size, (sgx_sealed_data_t *) *sealed);
 }
 
-sgx_status_t unseal_key_pair(const uint8_t *sealed, sgx_ec256_private_t *private, sgx_ec256_public_t *public) {
+static sgx_status_t unseal_key_pair(const uint8_t *sealed, sgx_ec256_private_t *private, sgx_ec256_public_t *public) {
     // invalid parameter handling
     if(sealed == NULL) {
         return SGX_ERROR_INVALID_PARAMETER;