diff --git a/plugins/dynamic-security/acl.c b/plugins/dynamic-security/acl.c
index 0b5fd5fe..c511e5f3 100644
--- a/plugins/dynamic-security/acl.c
+++ b/plugins/dynamic-security/acl.c
@@ -91,7 +91,7 @@ static int acl_check_subscribe(struct mosquitto_evt_acl_check *ed, struct dynsec
 {
 	struct dynsec__rolelist *rolelist, *rolelist_tmp;
 	struct dynsec__acl *acl, *acl_tmp;
-	int len;
+	size_t len;
 
 	len = strlen(ed->topic);
 
@@ -128,7 +128,7 @@ static int acl_check_unsubscribe(struct mosquitto_evt_acl_check *ed, struct dyns
 {
 	struct dynsec__rolelist *rolelist, *rolelist_tmp;
 	struct dynsec__acl *acl, *acl_tmp;
-	int len;
+	size_t len;
 
 	len = strlen(ed->topic);
 
diff --git a/plugins/dynamic-security/auth.c b/plugins/dynamic-security/auth.c
index 7ae1982f..f62a96f5 100644
--- a/plugins/dynamic-security/auth.c
+++ b/plugins/dynamic-security/auth.c
@@ -32,11 +32,13 @@ Contributors:
  * #
  * ################################################################ */
 
-int dynsec_auth__base64_encode(unsigned char *in, unsigned int in_len, char **encoded)
+int dynsec_auth__base64_encode(unsigned char *in, int in_len, char **encoded)
 {
 	BIO *bmem, *b64;
 	BUF_MEM *bptr;
 
+	if(in_len < 0) return 1;
+
 	b64 = BIO_new(BIO_f_base64());
 	BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
 	bmem = BIO_new(BIO_s_mem());
@@ -60,10 +62,10 @@ int dynsec_auth__base64_encode(unsigned char *in, unsigned int in_len, char **en
 }
 
 
-int dynsec_auth__base64_decode(char *in, unsigned char **decoded, unsigned int *decoded_len)
+int dynsec_auth__base64_decode(char *in, unsigned char **decoded, int *decoded_len)
 {
 	BIO *bmem, *b64;
-	int slen;
+	size_t slen;
 
 	slen = strlen(in);
 
@@ -79,7 +81,7 @@ int dynsec_auth__base64_decode(char *in, unsigned char **decoded, unsigned int *
 		return 1;
 	}
 	b64 = BIO_push(b64, bmem);
-	BIO_write(bmem, in, slen);
+	BIO_write(bmem, in, (int)slen);
 
 	if(BIO_flush(bmem) != 1){
 		BIO_free_all(b64);
@@ -90,7 +92,7 @@ int dynsec_auth__base64_decode(char *in, unsigned char **decoded, unsigned int *
 		BIO_free_all(b64);
 		return 1;
 	}
-	*decoded_len =  BIO_read(b64, *decoded, slen);
+	*decoded_len =  BIO_read(b64, *decoded, (int)slen);
 	BIO_free_all(b64);
 
 	if(*decoded_len <= 0){
@@ -133,7 +135,7 @@ int dynsec_auth__pw_hash(struct dynsec__client *client, const char *password, un
 		return MOSQ_ERR_UNKNOWN;
 	}
 
-	return !PKCS5_PBKDF2_HMAC(password, strlen(password),
+	return !PKCS5_PBKDF2_HMAC(password, (int)strlen(password),
 			client->pw.salt, sizeof(client->pw.salt), iterations,
 			digest, password_hash_len, password_hash);
 }
diff --git a/plugins/dynamic-security/clients.c b/plugins/dynamic-security/clients.c
index 05562d6d..a01ec141 100644
--- a/plugins/dynamic-security/clients.c
+++ b/plugins/dynamic-security/clients.c
@@ -104,7 +104,7 @@ int dynsec_clients__config_load(cJSON *tree)
 	struct dynsec__client *client;
 	struct dynsec__role *role;
 	unsigned char *buf;
-	unsigned int buf_len;
+	int buf_len;
 	int priority;
 	int iterations;
 
@@ -152,7 +152,7 @@ int dynsec_clients__config_load(cJSON *tree)
 				mosquitto_free(client);
 				continue;
 			}
-			iterations = jtmp->valuedouble;
+			iterations = (int)jtmp->valuedouble;
 			if(iterations < 1){
 				// FIXME log
 				mosquitto_free(client->username);
@@ -177,7 +177,7 @@ int dynsec_clients__config_load(cJSON *tree)
 					mosquitto_free(client);
 					continue;
 				}
-				memcpy(client->pw.salt, buf, buf_len);
+				memcpy(client->pw.salt, buf, (size_t)buf_len);
 				mosquitto_free(buf);
 
 				if(dynsec_auth__base64_decode(j_password->valuestring, &buf, &buf_len) != MOSQ_ERR_SUCCESS
@@ -188,7 +188,7 @@ int dynsec_clients__config_load(cJSON *tree)
 					mosquitto_free(client);
 					continue;
 				}
-				memcpy(client->pw.password_hash, buf, buf_len);
+				memcpy(client->pw.password_hash, buf, (size_t)buf_len);
 				mosquitto_free(buf);
 				client->pw.valid = true;
 			}else{
@@ -802,7 +802,7 @@ int dynsec_clients__process_list(cJSON *j_responses, struct mosquitto *context,
 	}
 	cJSON_AddItemToObject(tree, "data", j_data);
 
-	cJSON_AddIntToObject(j_data, "totalCount", HASH_CNT(hh, local_clients));
+	cJSON_AddIntToObject(j_data, "totalCount", (int)HASH_CNT(hh, local_clients));
 
 	j_clients = cJSON_CreateArray();
 	if(j_clients == NULL){
diff --git a/plugins/dynamic-security/dynamic_security.h b/plugins/dynamic-security/dynamic_security.h
index c00a4417..6e8a0aa2 100644
--- a/plugins/dynamic-security/dynamic_security.h
+++ b/plugins/dynamic-security/dynamic_security.h
@@ -156,8 +156,8 @@ bool sub_acl_check(const char *acl, const char *sub);
  * #
  * ################################################################ */
 
-int dynsec_auth__base64_encode(unsigned char *in, unsigned int in_len, char **encoded);
-int dynsec_auth__base64_decode(char *in, unsigned char **decoded, unsigned int *decoded_len);
+int dynsec_auth__base64_encode(unsigned char *in, int in_len, char **encoded);
+int dynsec_auth__base64_decode(char *in, unsigned char **decoded, int *decoded_len);
 int dynsec_auth__pw_hash(struct dynsec__client *client, const char *password, unsigned char *password_hash, int password_hash_len, bool new_password);
 int dynsec_auth__basic_auth_callback(int event, void *event_data, void *userdata);
 
diff --git a/plugins/dynamic-security/groups.c b/plugins/dynamic-security/groups.c
index b9739e36..1165f0e3 100644
--- a/plugins/dynamic-security/groups.c
+++ b/plugins/dynamic-security/groups.c
@@ -765,7 +765,7 @@ int dynsec_groups__process_list(cJSON *j_responses, struct mosquitto *context, c
 	}
 	cJSON_AddItemToObject(tree, "data", j_data);
 
-	cJSON_AddIntToObject(j_data, "totalCount", HASH_CNT(hh, local_groups));
+	cJSON_AddIntToObject(j_data, "totalCount", (int)HASH_CNT(hh, local_groups));
 
 	j_groups = cJSON_CreateArray();
 	if(j_groups == NULL){
diff --git a/plugins/dynamic-security/plugin.c b/plugins/dynamic-security/plugin.c
index 395543b3..837f15d2 100644
--- a/plugins/dynamic-security/plugin.c
+++ b/plugins/dynamic-security/plugin.c
@@ -26,6 +26,7 @@ Contributors:
 #include "mosquitto.h"
 #include "mosquitto_broker.h"
 #include "mosquitto_plugin.h"
+#include "mqtt_protocol.h"
 
 #include "dynamic_security.h"
 
@@ -56,13 +57,19 @@ void dynsec__command_reply(cJSON *j_responses, struct mosquitto *context, const
 static void send_response(cJSON *tree)
 {
 	char *payload;
+	size_t payload_len;
 
 	payload = cJSON_PrintUnformatted(tree);
 	cJSON_Delete(tree);
 	if(payload == NULL) return;
 
+	payload_len = strlen(payload);
+	if(payload_len > MQTT_MAX_PAYLOAD){
+		free(payload);
+		return;
+	}
 	mosquitto_broker_publish(NULL, "$CONTROL/dynamic-security/v1/response",
-			strlen(payload), payload, 0, 0, NULL);
+			(int)payload_len, payload, 0, 0, NULL);
 }
 
 
@@ -327,7 +334,7 @@ static int dynsec__general_config_save(cJSON *tree)
 static int dynsec__config_load(void)
 {
 	FILE *fptr;
-	long flen;
+	size_t flen;
 	char *json_str;
 	cJSON *tree;
 
@@ -338,7 +345,7 @@ static int dynsec__config_load(void)
 	}
 
 	fseek(fptr, 0, SEEK_END);
-	flen = ftell(fptr);
+	flen = (size_t)ftell(fptr);
 	fseek(fptr, 0, SEEK_SET);
 	json_str = mosquitto_calloc(flen+1, sizeof(char));
 	if(json_str == NULL){
@@ -385,10 +392,10 @@ static int dynsec__config_load(void)
 void dynsec__config_save(void)
 {
 	cJSON *tree;
-	int file_path_len;
+	size_t file_path_len;
 	char *file_path;
 	FILE *fptr;
-	int json_str_len;
+	size_t json_str_len;
 	char *json_str;
 
 	tree = cJSON_CreateObject();
diff --git a/plugins/dynamic-security/roles.c b/plugins/dynamic-security/roles.c
index fd8ae361..19cfb916 100644
--- a/plugins/dynamic-security/roles.c
+++ b/plugins/dynamic-security/roles.c
@@ -617,7 +617,7 @@ int dynsec_roles__process_list(cJSON *j_responses, struct mosquitto *context, cJ
 	}
 	cJSON_AddItemToObject(tree, "data", j_data);
 
-	cJSON_AddIntToObject(j_data, "totalCount", HASH_CNT(hh, local_roles));
+	cJSON_AddIntToObject(j_data, "totalCount", (int)HASH_CNT(hh, local_roles));
 
 	j_roles = cJSON_CreateArray();
 	if(j_roles == NULL){