diff --git a/demo/correct.txt b/demo/correct.txt
new file mode 100644
index 0000000..9579c66
Binary files /dev/null and b/demo/correct.txt differ
diff --git a/demo/demo.cpp b/demo/demo.cpp
new file mode 100644
index 0000000..e69845b
--- /dev/null
+++ b/demo/demo.cpp
@@ -0,0 +1,257 @@
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <pwd.h>
+#include <grp.h>
+#include <time.h>
+#include <locale.h>
+#include <langinfo.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <arpa/inet.h>
+
+#include "gquic_process.h"
+#include "quic_analysis.h"
+#include "parser_quic.h"
+
+static int check_length(int last_len, int field_len)
+{
+	return ((last_len-field_len>0) ? 1 : 0);
+}
+
+
+int get_quic_tlv(char *start_pos, quic_tlv_t *tlv, int len, int type, int thread_seq)
+{
+	if(tlv->value==NULL && len>0)
+	{
+		tlv->value=(char *)calloc(1, len+1);
+		memset(tlv->value, 0, len+1);
+		tlv->length=len;
+		tlv->type=type;
+		memcpy(tlv->value, start_pos, tlv->length);
+	}
+	
+	return 0;
+}
+
+static int get_value(unsigned char *payload, int *offset, int len)
+{
+	switch(len)
+	{
+		case	1:
+			return (int)(payload[(*offset)++]);
+			break;
+		case	2:
+			(*offset)+=len;
+			return (int)ntohs(*(unsigned short *)(payload+*offset-len));
+			break;
+		case	3:
+			(*offset)+=len;
+			return ((int)*(payload-2+*offset)<<16|
+		           (int)*(payload-1+*offset)<<8|
+		           (int)*(payload+*offset)<<0);
+			break;
+		case	4:
+			(*offset)+=len;
+			return (int)ntohl(*(unsigned int *)(payload+*offset-len));
+			break;
+		case	32:
+			(*offset)+=len;
+			return 0;
+			break;
+		default:
+			break;
+	}
+
+	return 0;
+}
+
+int parse_encrypt_parameter(struct _quic_stream *quic_stream, unsigned char *payload, int payload_len, int thread_seq)
+{
+	int used_len=0,length=0;
+	while(payload_len>used_len)
+	{
+		if(payload[used_len]> 0x00 && payload[used_len]<=0x20)
+		{
+			get_value(payload, &used_len, 1);  //type=1
+			length=get_value(payload, &used_len, 1); // length=1
+			used_len+=length; 
+
+			continue;
+		}
+
+		if((*(unsigned short *)(payload+used_len)) == htons(EXT_QUIC_PARAM_USER_AGENT))
+		{
+			quic_stream->ua_idx=quic_stream->ext_tag_num++;
+			get_value(payload, &used_len, 2);  //type=2
+			length=get_value(payload, &used_len, 1); // length=1
+			get_quic_tlv((char *)payload+used_len, &(quic_stream->ext_tags[quic_stream->ua_idx]), length, EXT_QUIC_PARAM_USER_AGENT, thread_seq);
+			used_len+=length;
+
+			continue;
+		}
+
+		if(*(unsigned int *)(payload+used_len) == htonl(EXT_QUIC_PARAM_QUIC_VERSION))
+		{
+			quic_stream->ver_idx=quic_stream->ext_tag_num++;
+			get_value(payload, &used_len, 4);  //type=4
+			length=get_value(payload, &used_len, 1); // length=1
+			get_quic_tlv((char *)payload+used_len, &(quic_stream->ext_tags[quic_stream->ver_idx]), length, EXT_QUIC_PARAM_QUIC_VERSION, thread_seq);
+			*(unsigned int *)quic_stream->ext_tags[quic_stream->ver_idx].value=(unsigned int)htonl(*(unsigned int *)quic_stream->ext_tags[quic_stream->ver_idx].value);
+			used_len+=length;
+
+			continue;
+		}
+
+		if((*(unsigned int *)(payload+used_len))== htonl(EXT_QUIC_PARAM_GREASE_HIGH4) && (*(unsigned int *)(payload+used_len+4))== htonl(EXT_QUIC_PARAM_GREASE_LOW4))
+		{
+			used_len+=8;  //type=8
+			length=get_value(payload, &used_len, 1); // length=1
+			used_len+=length;
+
+			continue;
+		}
+
+		break;
+	}
+
+	return 0;
+}
+
+int parse_encrypt_server_name(struct _quic_stream *quic_stream, unsigned char *payload, int payload_len, int thread_seq)
+{
+	int ext_len=0,used_len=0;
+	
+	quic_stream->sni_idx=quic_stream->ext_tag_num++;
+	get_value(payload, &used_len, 2);  //Server Name List length
+	if(get_value(payload, &used_len, 1)==0)  //Server Name type
+	{
+		ext_len=get_value(payload, &used_len, 2);  //Server Name length
+		get_quic_tlv((char *)payload+used_len, &(quic_stream->ext_tags[quic_stream->sni_idx]), ext_len, EXTENSION_SERVER_NAME, thread_seq);
+	}
+
+	return 1;
+}
+
+int parse_encrypt_client_hello(void *pstream, struct _quic_stream *quic_stream, void *a_packet, unsigned char *payload, int payload_len)
+{
+	int used_len=0;
+	int flags=0;
+	int skip_len=0,client_hello_len=0;
+	int ext_type=0, extension_total_len=0;
+
+	get_value(payload, &used_len, 1);  //handshake type
+	client_hello_len=get_value(payload, &used_len, 3); //client hello length
+	get_value(payload, &used_len, 2); //ssl_version
+
+	get_value(payload, &used_len, 32);  //Random
+
+	skip_len=(int)get_value(payload, &used_len, 1);  //Session ID length
+	if(!check_length(payload_len-used_len, skip_len))
+	{
+		return flags;
+	}
+	used_len+=skip_len;
+
+	skip_len=(int)get_value(payload, &used_len, 2);  //Ciper Suites length
+	if(!check_length(payload_len-used_len, skip_len))
+	{
+		return flags;
+	}
+	used_len+=skip_len;
+
+	skip_len=(int)get_value(payload, &used_len, 1);  //Compression Methods
+	if(!check_length(payload_len-used_len, skip_len))
+	{
+		return flags;
+	}
+	used_len+=skip_len;
+
+	extension_total_len=(int)get_value(payload, &used_len, 2);  //Extension length
+	if(!check_length(payload_len-used_len, extension_total_len))
+	{
+		return flags;
+	}
+
+	quic_stream->ext_tags=(quic_tlv_t *)calloc(1, sizeof(quic_tlv_t)*3);
+	memset(quic_stream->ext_tags, 0, sizeof(quic_tlv_t)*3);
+	
+	while(extension_total_len>used_len)
+	{
+		ext_type=get_value(payload, &used_len, 2);  //Extension type		
+		skip_len=get_value(payload, &used_len, 2);	//length
+		if(!check_length(payload_len-used_len, skip_len) || skip_len==0)
+		{
+			return flags;
+		}
+				
+		switch(ext_type)
+		{
+			case	EXTENSION_SERVER_NAME:
+				parse_encrypt_server_name(quic_stream, payload+used_len, skip_len, 0);
+				flags=1;
+				break;
+			case	EXTENSION_QUIC_PARAM:
+				parse_encrypt_parameter(quic_stream, payload+used_len, skip_len, 0);
+				break;
+			case	EXTENSION_SUPPORT_GROUP:
+			case	EXTENSION_APP_PROT_NEGO:
+			case	EXTENSION_SIG_ALGORITHM:
+			case	EXTENSION_KEY_SHARE:
+			case	EXTENSION_PSK_EXCHANGE:
+			case	EXTENSION_SUPP_SSL_VER:
+			case	EXTENSION_COMPRESS_CERT:
+				break;
+			default:
+				break;
+		}
+		
+		used_len+=skip_len;
+	}
+	
+	return flags;
+}
+
+
+int main(int argc, char *argv[])
+{
+	if(argc<1)
+	{
+		return -1;
+	}
+
+	struct stat statbuf;
+	if (stat(argv[1], &statbuf) == -1)
+	{
+		return -1;
+	}
+
+	unsigned char *payload=(unsigned char *)calloc(1, statbuf.st_size);
+	FILE *fp=fopen(argv[1], "rb");
+	if(fp)
+	{
+		int size=fread(payload, 1, 1315, fp);
+		assert(size==1315);
+		//assert(size==statbuf.st_size);
+			
+		struct _quic_stream * quic_stream=(struct _quic_stream *)calloc(1, sizeof(struct _quic_stream));
+		parse_encrypt_client_hello(NULL, quic_stream, NULL, payload+4, 1314)-4;
+
+		fclose(fp);
+		fp=NULL;
+
+		free(quic_stream);
+		quic_stream=NULL;
+
+		free(payload);
+		payload=NULL;
+		
+	}
+
+	return 0;
+}
diff --git a/demo/error.txt b/demo/error.txt
new file mode 100644
index 0000000..42e9bd9
Binary files /dev/null and b/demo/error.txt differ
diff --git a/src/gquic_process.cpp b/src/gquic_process.cpp
index bce6600..f74ec57 100644
--- a/src/gquic_process.cpp
+++ b/src/gquic_process.cpp
@@ -15,6 +15,7 @@
 #include "quic_analysis.h"
 #include "parser_quic.h"
 
+
 int is_iquic(enum _QUIC_VERSION quic_version)
 {
 	switch(quic_version)
@@ -707,7 +708,7 @@ int gquic_frame_type_stream(struct streaminfo *pstream, struct _quic_context* _c
 	{
 		case	GQUIC_VERSION_Q041:
 			*used_len+=1; // unknown
-		case	GQUIC_VERSION_Q044:
+		//case	GQUIC_VERSION_Q044:
 			message_tag=(unsigned int)ntohl(*(unsigned int *)(payload+*used_len));
 			*used_len+=4;
 
@@ -1056,15 +1057,31 @@ int parse_encrypt_client_hello(struct streaminfo *pstream, struct _quic_stream *
 	get_value(payload, &used_len, 32);  //Random
 
 	skip_len=(int)get_value(payload, &used_len, 1);  //Session ID length
+	if(!check_length(payload_len-used_len, skip_len))
+	{
+		return flags;
+	}
 	used_len+=skip_len;
 
 	skip_len=(int)get_value(payload, &used_len, 2);  //Ciper Suites length
+	if(!check_length(payload_len-used_len, skip_len))
+	{
+		return flags;
+	}
 	used_len+=skip_len;
 
 	skip_len=(int)get_value(payload, &used_len, 1);  //Compression Methods
+	if(!check_length(payload_len-used_len, skip_len))
+	{
+		return flags;
+	}
 	used_len+=skip_len;
 
 	extension_total_len=(int)get_value(payload, &used_len, 2);  //Extension length
+	if(!check_length(payload_len-used_len, extension_total_len))
+	{
+		return flags;
+	}
 
 	quic_stream->ext_tags=(quic_tlv_t *)dictator_malloc(pstream->threadnum, sizeof(quic_tlv_t)*3);
 	memset(quic_stream->ext_tags, 0, sizeof(quic_tlv_t)*3);
@@ -1073,6 +1090,11 @@ int parse_encrypt_client_hello(struct streaminfo *pstream, struct _quic_stream *
 	{
 		ext_type=get_value(payload, &used_len, 2);  //Extension type		
 		skip_len=get_value(payload, &used_len, 2);	//length
+		if(!check_length(payload_len-used_len, skip_len))
+		{
+			return flags;
+		}
+				
 		switch(ext_type)
 		{
 			case	EXTENSION_SERVER_NAME:
@@ -1120,7 +1142,7 @@ int parse_decrypt_quic(struct streaminfo *pstream, struct _quic_context* _contex
 				_context->quic_info.client_hello=(struct _quic_stream *)dictator_malloc(pstream->threadnum, sizeof(struct _quic_stream));
 				memset(_context->quic_info.client_hello, 0, sizeof(struct _quic_stream));
 			}
-			ret=parse_encrypt_client_hello(pstream, _context->quic_info.client_hello, a_packet, payload+*used_len, payload_len); //Frame Type=1, offset=1, length=2
+			ret=parse_encrypt_client_hello(pstream, _context->quic_info.client_hello, a_packet, payload+*used_len, payload_len-*used_len); //Frame Type=1, offset=1, length=2
 			if(ret>0 && _context->call_business)
 			{
 				state=quic_callPlugins(pstream, _context, (void *)(_context->quic_info.client_hello), sizeof(void *), QUIC_CLIENT_HELLO_MASK, a_packet);
@@ -1183,7 +1205,7 @@ int quic_process(struct streaminfo *pstream, struct _quic_context* _context, int
 				ret=parse_gquic_Q046(pstream, _context, a_packet, (char *)udp_detail->pdata, udp_detail->datalen, &used_len);
 				break;
 			default:
-				if(is_gquic>=GQUIC_VERSION_Q001 && is_gquic<=GQUIC_VERSION_Q043)
+				if(is_gquic>=GQUIC_VERSION_Q001 && is_gquic<=GQUIC_VERSION_Q046)
 				{
 					ret=gquic_proc_unencrypt(pstream, _context, a_packet, (char *)udp_detail->pdata, udp_detail->datalen, &used_len);
 				}