diff --git a/crc.c b/crc.c
index 58df9c2..9f49530 100644
--- a/crc.c
+++ b/crc.c
@@ -1,12 +1,16 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <string.h>
+#include <stdlib.h>
+#include <sodium.h>
 #include "CRCLib.h"
 
-int png_signature[8] = { 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a };
-//int idat_signature[4] = { 0x, 0x, 0x, 0x}
+const int png_signature[8] = { 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a };
+const int idat_signature = 1229209940;
+const int iend_signature = 1229278788;
+const int working = 1;
 
-int check_header(int *addr) {
+int check_file_header(int *addr) {
 	int signature_match = 0;
 	for( int i = 0; i < 8; i++ ) {
 		if (addr[i] != png_signature[i]) {
@@ -38,9 +42,7 @@ int first_idat(int *addr) {
 	while(idat_found == 0) {
 		jump_offset = check_header_length(addr, offset);
 		header_type = check_header_length(addr, offset+4);
-		printf("Jump: %d\n", jump_offset);
-		printf("Type: %d\n", header_type);
-		if(header_type == 1229209940) {
+		if(header_type == idat_signature) {
 			idat_found = 1;
 		} else {
 			offset = offset + jump_offset + 12;
@@ -49,23 +51,94 @@ int first_idat(int *addr) {
 	return offset;
 }
 
-void main() {
+int total_idat(int *addr) {
+	int iend_found = 0;
+	int found_idat = 0;
+	int offset = 8;
+	int jump_offset = 0;
+	int header_type = 0;
+	while(iend_found == 0) {
+		jump_offset = check_header_length(addr, offset);
+		header_type = check_header_length(addr, offset+4);
+		if(header_type == iend_signature) {
+			iend_found = 1;
+		} else {
+			if(header_type == idat_signature) {
+				found_idat++;
+			}
+			offset = offset + jump_offset + 12;
+		}
+	}
+	return found_idat;
+}
+
+int change_idat_content(int *addr, char *message, int accuracy, int offset) {
+	printf("Starting IDAT Tranform");
+	if(accuracy > 4) {
+		printf("Warning, accuracy cannot be larger than 4");
+		return EXIT_FAILURE;
+	}
+	if(accuracy > 2) {
+		printf("Notice, this could take a long time...");
+	}
+	if(total_idat(addr) < strlen(message)) {
+		printf("Warning, message exceeds IDAT amount");
+		return EXIT_FAILURE;
+	}
+
+	// Comment
+	int i = total_idat(addr);
+	printf("Total IDAT %d\n", i);
+
+	int idat_length = check_header_length(addr, offset);
+	int prop_found = 0;
+	int size = 1;
+	int* idat_data = malloc(size * sizeof(int));
+	while(prop_found == 0) {
+		for(i = 0; i < idat_length; i++) {
+			idat_data[i] = addr[i+offset+8];
+			size++;
+			int* new_idat_data = realloc(idat_data, size * sizeof(int));
+		}
+		int r = randombytes_uniform(5) + 1;
+		int j = randombytes_uniform(idat_length);
+		
+		idat_data[j] = (idat_data[j] + r) % 255;
+		unsigned char crc_check[size+4];
+		int idat_header[] = { 0x49, 0x44, 0x41, 0x54 };
+		for(i = 0; i < 4; i++) {
+			crc_check[i] = idat_header[i];
+		}
+		for(i = 0; i < size; i++) {
+			crc_check[i] = idat_data[i+4];
+		}
+		int crcnum = crc(crc_check, idat_length);
+		printf("New CRC: %08X\n", crcnum);
+		printf("Test: %X\n", crcnum >> (8*3));
+		prop_found = 1;
+	}
+
+	return 0;
+}
+
+int main() {
 	FILE *fp;
 	int c;
 	int myArray[255] = {};
 	int i = 0;
 	int offset = 0;
+	char message[1];
+	if(sodium_init() == -1) {
+		return EXIT_FAILURE;
+	}
 	fp = fopen("./1.png", "rt");
 	while((c = fgetc(fp)) != EOF) {
 		myArray[i] = c;
 		i++;
 	}
 	fclose(fp);
-	//check_header(myArray);
-	//check_header_length(myArray, 54);
 	offset = first_idat(myArray);
-	printf("First Chunk: %d\n", offset);
-	//printf("%d\n", CheckPNG(myArray));
+	change_idat_content(myArray, message, 2, offset);
 	//int crcnum = crc(myArray, 19);
 	//printf("%08X\n", crcnum);
 }