diff --git a/crc.c b/crc.c
index 8d158e9..a9c1f78 100644
--- a/crc.c
+++ b/crc.c
@@ -4,6 +4,7 @@
 #include <stdlib.h>
 #include <sodium.h>
 #include "CRCLib.h"
+#include "crc.h"
 
 const long png_signature[8] = { 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a };
 const long idat_signature = 1229209940;
@@ -34,7 +35,7 @@ int check_header_length(unsigned char *addr, long offset) {
 	return res;
 }
 
-unsigned long first_idat(char *addr) {
+unsigned long first_idat(unsigned char *addr) {
 	int idat_found = 0;
 	unsigned long offset = 8;
 	int jump_offset = 0;
@@ -51,7 +52,7 @@ unsigned long first_idat(char *addr) {
 	return offset;
 }
 
-int total_idat(char *addr) {
+int total_idat(unsigned char *addr) {
 	int iend_found = 0;
 	int found_idat = 0;
 	unsigned long offset = 8;
@@ -72,6 +73,15 @@ int total_idat(char *addr) {
 	return found_idat;
 }
 
+int update_file_crc(unsigned char *addr, unsigned long offset , unsigned int crc_num) {
+	int startCRC = 8 + offset + check_header_length(addr, offset);
+	unsigned char new_crc;
+	for(int i = 0; i < 4; i++) {
+		new_crc = crc_num >> (8*(3-i)) & 0xFF;
+		addr[startCRC+i] = new_crc;
+	}
+}
+
 int change_idat_content(unsigned char *addr, char *message, int accuracy, unsigned long offset) {
 	printf("Starting IDAT Tranform\n");
 	if(accuracy > 4) {
@@ -125,6 +135,8 @@ int change_idat_content(unsigned char *addr, char *message, int accuracy, unsign
 			printf("Full CRC: %08X\n", crcnum);
 			printf("Original: %02X\n", idat_data[j]);
 			printf("Change offset: %d to hex: %02X\n", j, temp_idat_data[j]);
+			addr[offset+8+j] = temp_idat_data[j];
+			update_file_crc(addr, offset, crcnum);
 			prop_found = 1;
 		}
 	}
@@ -132,12 +144,24 @@ int change_idat_content(unsigned char *addr, char *message, int accuracy, unsign
 	return 0;
 }
 
+int create_cc_file(unsigned char *addr, unsigned long file_length) {
+	FILE *fp;
+	fp = fopen("png2.png", "w");
+
+	if(fp == NULL) {
+		return EXIT_FAILURE;
+	}
+
+	for(int i = 0; i < file_length; i++){
+		fputc(addr[i], fp);
+	}
+	fclose(fp);
+}
+
 int main() {
 	FILE *fp;
 	unsigned int c;
-	//unsigned char myArray[838860];
-	unsigned char * myArray = NULL;
-	myArray = calloc(880388560, sizeof(char));
+	unsigned char* myArray = calloc(1000, sizeof(unsigned char));
 	unsigned long i = 0;
 	unsigned long offset = 0;
 	char message[1];
@@ -152,6 +176,7 @@ int main() {
 	fclose(fp);
 	offset = first_idat(myArray);
 	change_idat_content(myArray, message, 2, offset);
+	create_cc_file(myArray, i);
 	//int crcnum = crc(myArray, 19);
 	//printf("%08X\n", crcnum);
 }
diff --git a/crc.h b/crc.h
new file mode 100644
index 0000000..3673550
--- /dev/null
+++ b/crc.h
@@ -0,0 +1,6 @@
+
+int check_file_header(char *addr);
+int check_header_length(unsigned char *addr, long offset);
+unsigned long first_idat(unsigned char *addr);
+int total_idat(unsigned char *addr);
+int change_idat_content(unsigned char *addr, char *message, int accuracy, unsigned long offset);