Update

Signed-off-by: Pin <wf6DJd8a3xSSCZbn@protonmail.com>

README.md

@@ -0,0 +1,37 @@
+# PSPNG
+
+Sample program to embed messages into PNG images
+
+## Install
+
+**NOTE:** Set the core_count variable to one value lower than maximum cores on the host in cmd/pspng.c
+
+Requires zlib, pthread, and sodium header files to compile (These will be distro specific packages)
+
+Build:
+
+```bash
+make
+```
+
+System Wide:
+
+```bash
+make
+make install
+```
+
+## Usage
+
+Embed Message:
+
+pspng --compress -f {input file name} -o {output file name} -m "{input message}"
+
+Extract Message:
+
+pspng --uncompress -f {input file name}
+
+Help Message:
+
+pspng --help
+

cmd/pspng.c

@@ -8,6 +8,7 @@
 #include <sodium.h>
 #include <getopt.h>
 #include <pthread.h>
+#include <math.h>
 #include "crc_util.h"
 #include "CRCLib.h"
 #include "pspng.h"
@@ -70,11 +71,74 @@ int update_file_crc(unsigned char *addr, unsigned long offset , unsigned int crc
 	return 0;
 }
 
-static void random_window_bit_change(unsigned char *data, int width, int rounds, int color_range, size_t length, size_t offset) {
+static unsigned char* create_raw_pixel_values(unsigned char *data, int width, int color_range, size_t length) {
+	// Generating twice the size we migth need
+	length = length * 4;
+	//length = 500000;
+	unsigned char* raw_data = calloc(length, sizeof(unsigned char*));
+	size_t filter_chunk_byte = 0;
+
+	for(size_t i = 0; i < length; i++) {
+		filter_chunk_byte = i  - (i % ((width * color_range) + 1));
+		// Grabbing raw pixel data
+		if(data[filter_chunk_byte] == 0) {
+			// Filter: None
+			raw_data[i] = data[i];
+		} else if(data[filter_chunk_byte] == 1) {
+			// Filter: Sub
+			if ((i % ((width * color_range) + 1)) == 0) {
+				// Setting filter type
+				raw_data[i] = data[i];
+			} else if ((i - filter_chunk_byte) <= color_range) {
+				// Setting initial color_range byte
+				raw_data[i] = data[i];
+			} else {
+				// Setting remaining bytes
+				raw_data[i] = data[i] + raw_data[i - color_range];
+			}
+		
+		} else if(data[filter_chunk_byte] == 3) {
+			// Filter: Average
+			if((i % ((width * color_range) + 1)) == 0) {
+				// Setting filter type
+				raw_data[i] = data[i];
+			} else {
+				// Setting remaining bytes
+				if(filter_chunk_byte == 0) {
+					// If no scanline is present before current
+					if((i - filter_chunk_byte) <= color_range) {
+						// If no pixel present before current
+						raw_data[i] = data[i] + floor((0 + 0) / 2);
+					} else {
+						// If pixel present before current
+						raw_data[i] = data[i] + floor((data[i - color_range] + 0) / 2);
+					}
+				
+				} else {
+					// Scanline is present before current
+					if((i - filter_chunk_byte) <= color_range) {
+						// If no pixel present before current
+						raw_data[i] = data[i] + floor((0 + raw_data[i - ((width * color_range) + 1)]) / 2);
+					} else {
+						// If pixel present before current
+						raw_data[i] = data[i] + floor((raw_data[i - color_range] + raw_data[i - ((width * color_range) + 1)]) / 2);
+					}
+				}
+			}
+		
+		} else {
+			// Filter: Error Unsupported
+			printf("Exiting due to unsupported filter type\n");
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	return raw_data;
+}
+
+static void random_window_bit_change(unsigned char *data, unsigned char *raw_data, int width, int rounds, int color_range, size_t length, size_t offset) {
 	size_t random_num = 0;
 	size_t filter_chunk_byte = 0;
-	size_t change_num = 0;
-	long prior_chuck_check = 0;
 	for (int i = 0; i < rounds; i++) {
 		random_num = 0;
 		do {
@@ -86,24 +150,30 @@ static void random_window_bit_change(unsigned char *data, int width, int rounds,
 			// None Filter Type Change
 			if(data[random_num] == 255) {
 				data[random_num]--;
+				raw_data[random_num]--;
 			} else {
 				data[random_num]++;
+				raw_data[random_num]++;
 			}
 		} else if(data[filter_chunk_byte] == 1) {
 			// Sub Filter Type Change
 			if(data[random_num] == 255) {
 				data[random_num]--;
-				change_num = 1;
+				raw_data[random_num]--;
 			} else {
 				data[random_num]++;
-				change_num = -1;
+				raw_data[random_num]++;
 			}
-			// Starting after random change
-			for(int j = 1; j < 2; j++) {
-				data[random_num+(color_range * j)] = (data[random_num+(color_range * j)] + change_num) % 256;
+			// Fixing Next Pixel in Scanline
+			if(!(random_num+3 > (filter_chunk_byte + (width * color_range) + 1))){
+				data[random_num+color_range] = raw_data[random_num+color_range] - raw_data[random_num];
+			}
+			// Checking Next Scanline type
+			if(data[filter_chunk_byte+((width * color_range) + 1)] == 3){
+				data[random_num+((width * color_range)+1)] = raw_data[random_num+((width * color_range)+1)] - floor((raw_data[random_num+((width * color_range)+1)-color_range] + raw_data[random_num]) / 2);
 			}
 		} else if(data[filter_chunk_byte] == 2) {
-			printf("2\n");
+			// Add Support
 			if(data[random_num] == 255) {
 				data[random_num]--;
 			} else {
@@ -111,21 +181,26 @@ static void random_window_bit_change(unsigned char *data, int width, int rounds,
 			}
 		} else if(data[filter_chunk_byte] == 3) {
 			// Average Filter Type Change
-			//printf("HEE: %d\n", data[(filter_chunk_byte - (width * color_range))-1]);
-			prior_chuck_check = filter_chunk_byte;
-			do {
-				//printf("C: %d\n", data[prior_chuck_check]);
-				prior_chuck_check = (prior_chuck_check - (width * color_range)-1);
-				//printf("CH: %ld\n", prior_chuck_check);
-			} while(prior_chuck_check >= 0);
-
-			if(data[random_num] == 255) {
-				data[random_num]--;
+			if(raw_data[random_num] == 255) {
+				raw_data[random_num]--;
 			} else {
-				data[random_num]++;
+				raw_data[random_num]++;
+			}
+			// Update Current Pixel
+			data[random_num] = raw_data[random_num] - floor((raw_data[random_num-color_range] + 
+						raw_data[random_num-((width * color_range) + 1)]) / 2);
+			// Fixing Next Pixel in Scanline
+			if(!(random_num+color_range > (filter_chunk_byte + (width * color_range) + 1))){
+				data[random_num+color_range] = raw_data[random_num+color_range] - 
+					floor((raw_data[random_num] + raw_data[random_num-((width * color_range)+ 1)+color_range]) / 2);
+			}
+			// Checking Next Scanline type
+			if(data[filter_chunk_byte+((width * color_range) + 1)] == 3){
+				data[random_num+((width * color_range)+1)] = raw_data[random_num+((width * color_range)+1)] - 
+					floor((raw_data[random_num+((width * color_range)+1)-color_range] + raw_data[random_num]) / 2);
 			}
 		} else if(data[filter_chunk_byte] == 4) {
-			printf("4\n");
+			// Add Support
 			if(data[random_num] == 255) {
 				data[random_num]--;
 			} else {
@@ -180,23 +255,39 @@ static int verify_crc_chunks(unsigned char *data, size_t data_length, int crc_de
 	return 0;
 }
 
-static int crc_embed_data(unsigned char *data, unsigned int data_length, int bit_width, int color_range, unsigned int sliding_window, char message, size_t offset , size_t iteration) {
+static int crc_embed_data(unsigned char *data, unsigned int data_length, int bit_width, int color_range, unsigned int sliding_window, char message, size_t offset , size_t iteration, size_t prior_offset) {
 	unsigned char *check_data;
+	unsigned char *raw_data;
+	unsigned char *new_data = calloc(1, sizeof(unsigned char));
 	size_t check_data_length = 0;
+	int match_crc = 1;
 	
-	random_window_bit_change(data, bit_width, 2, color_range, sliding_window, offset);
+	raw_data = create_raw_pixel_values(data, bit_width, color_range, sliding_window);
+	random_window_bit_change(data, raw_data, bit_width, 2, color_range, sliding_window, offset);
 
-	// Compressing data for test
+	//if(offset > 500000) {
+	if(offset == -1) {
+		new_data = calloc(300000, sizeof(unsigned char));
+		for(int k = 0; k < 300000; k++) {
+			new_data[k] = data[offset-(offset-prior_offset-1)+k];
+		}
+		zlib_compress_data(new_data, 100000, &check_data, &check_data_length);
+		match_crc = verify_crc_chunks(check_data, check_data_length, 1, MAX_IDAT_SIZE, message, 1);
+	} else {
 		zlib_compress_data(data, data_length, &check_data, &check_data_length);
-
-	int match_crc = verify_crc_chunks(check_data, check_data_length, 1, MAX_IDAT_SIZE, message, iteration);
+		match_crc = verify_crc_chunks(check_data, check_data_length, 1, MAX_IDAT_SIZE, message, iteration);
+	}
 
 	if(match_crc == 0) {
 		printf("COM SIZE: %zu\n", check_data_length);
+		free(new_data);
 		free(check_data);
+		free(raw_data);
 		return 0;
 	}
+	free(new_data);
 	free(check_data);
+	free(raw_data);
 	return 1;
 }
 
@@ -209,21 +300,21 @@ void *random_data_change_thread_call(void *w) {
 		// Creating temporary data set
 		memcpy(temp_color_data, data->data, data->uncom_data_len);
 
-		// Look into testing these values more
+		// Look into testing these values more for speed
 		if(data->uncom_data_len > 800000) {
 			data->data_len = 90000 + (90000 * data->cur_iteration);
 		} else {
 			data->data_len = data->uncom_data_len;
 		}
-		if(data->uncom_data_len > 16000) {
-			data->win_size = 9000 + (9000 * data->cur_iteration);
+		if(data->uncom_data_len > 36000) {
+			data->win_size = 36000 + (36000 * data->cur_iteration);
 		} else {
 			data->win_size = data->uncom_data_len;
 		}
 
 		cur_message = data->message[data->cur_iteration];
 
-		searching = crc_embed_data(temp_color_data, data->data_len, data->width, data->color_range, data->win_size, cur_message, data->cur_offset, data->cur_iteration);
+		searching = crc_embed_data(temp_color_data, data->data_len, data->width, data->color_range, data->win_size, cur_message, data->cur_offset, data->cur_iteration, data->offset[data->cur_iteration-1]);
 
 		pthread_mutex_lock(&data->mutex_lock);
 		if (searching == 0 && *data->searching == 1) {
@@ -247,6 +338,7 @@ size_t generate_offset(unsigned char *data, size_t data_len, size_t iteration) {
 	size_t uncom_data_size = 0;
 
 	printf("Gen Offset\n");
+	// See if we can make this call faster
 	zlib_compress_data(data, data_len, &com_data_buff, &com_data_size);
 
 	zlib_decompress_data(com_data_buff, (MAX_WINDOW_SIZE * (iteration+1)), &uncom_data_buff, &uncom_data_size);
@@ -260,7 +352,7 @@ size_t generate_offset(unsigned char *data, size_t data_len, size_t iteration) {
 
 void random_data_change(unsigned char *color_data, unsigned char *width, size_t length, char *message) {
 	int searching = 1;
-	int core_count = 24;
+	int core_count = 28;
 	unsigned int sliding_window = 0;
 	unsigned int compress_data_length = 0;
 	// Needs to be turned into a variable
@@ -279,11 +371,13 @@ void random_data_change(unsigned char *color_data, unsigned char *width, size_t
 		printf("Mutex Lock Error\n");
 		return;
 	}
+	// Building Struct Data
 	t_data->searching = &searching;
 	t_data->message = message;
 	t_data->data = color_data;
 	t_data->data_len = compress_data_length;
 	t_data->uncom_data_len = length;
+	// Original Offset set to 0
 	t_data->cur_offset = 0;
 	t_data->width = be32toh(w.width_int);
 	t_data->color_range = color_range;
@@ -307,7 +401,10 @@ void random_data_change(unsigned char *color_data, unsigned char *width, size_t
 
 		// Only generate new offset if not last char in message
 		if(j != (strlen(message) - 1)) {
-			t_data->cur_offset = generate_offset(color_data, t_data->uncom_data_len, j);
+			// Changing offset check size to not be full length of picture to speed up generation
+			//t_data->cur_offset = generate_offset(color_data, t_data->uncom_data_len, j);
+			t_data->cur_offset = generate_offset(color_data, (200000 * (j+1)), j);
+			t_data->offset[j] = t_data->cur_offset;
 		}
 	}
 	return;
@@ -417,13 +514,14 @@ unsigned char* populate_idat_array(unsigned char *addr, unsigned long offset, si
 
 int change_idat_content(unsigned char *addr, struct PNG_FILE_STRUCT *png_file, char *message, int accuracy, unsigned long offset, char *out_file_name) {
 	if(accuracy > 4) {
+		// Accuracy is currently unused
 		printf("Warning, accuracy cannot be larger than 4");
 		return EXIT_FAILURE;
-	}
-	if(accuracy > 2) {
+	} else if (accuracy > 2) {
 		printf("Notice, this could take a long time...");
 	}
-	if(total_idat(addr) < strlen(message)) {
+	// Checking if total IDAT / 4 (Since Sliding Window is assumed to be 32k)
+	if((total_idat(addr) / 4) < strlen(message)) {
 		printf("Warning, message exceeds IDAT amount\n");
 		exit(EXIT_FAILURE);
 	}
@@ -431,20 +529,16 @@ int change_idat_content(unsigned char *addr, struct PNG_FILE_STRUCT *png_file, c
 	size_t idat_byte_length = 0;
 	unsigned char *idat_data = populate_idat_array(addr, offset, &idat_byte_length);
 
-	unsigned char* temp_idat_data = calloc(idat_byte_length, sizeof(unsigned char));
-	memcpy(temp_idat_data, idat_data, idat_byte_length);
-
 	// Decompressing Data
 	unsigned char *uncom_data_buff = NULL;
 	size_t uncom_data_size = 0;
-	zlib_decompress_data(temp_idat_data, idat_byte_length, &uncom_data_buff, &uncom_data_size);
+	zlib_decompress_data(idat_data, idat_byte_length, &uncom_data_buff, &uncom_data_size);
 
 	printf("ORIG UNCOM LEN: %zu\n", uncom_data_size);
 
 	// Start data testing
 	random_data_change(uncom_data_buff, png_file->png_start_data.file_width, uncom_data_size, message);
 	
-	//return 0;
 	// Compress Data
 	unsigned char *com_data_buff;
 	size_t com_data_size = 0;
@@ -467,7 +561,6 @@ int change_idat_content(unsigned char *addr, struct PNG_FILE_STRUCT *png_file, c
 	free(uncom_data_buff);
 	free(com_data_buff);
 	free(idat_data);
-	free(temp_idat_data);
 	free(png_file->png_idat_data.idat_data);
 
 	return 0;
@@ -570,35 +663,29 @@ int main(int argc, char **argv) {
 	if(uncompress_call == 1) {
 		size_t idat_byte_length = 0;
 		unsigned long cur_idat_len = 0;
-		//unsigned char message_data[8192];
 		unsigned char* idat_data = populate_idat_array(file_data, offset, &idat_byte_length);
 
-		//for(int i = 0; i < idat_byte_length; i++) {
-			//printf("%02X ", idat_data[i]);
-		//}
-		printf("\nDecompressed Data:\n\n");
-		// Decompressing data
-		//unsigned char *uncom_data_buff = NULL;
-		//size_t uncom_data_size = 0;
-		//zlib_decompress_data(idat_data, idat_byte_length, &uncom_data_buff, &uncom_data_size);
-		//for(int i = 0; i < uncom_data_size; i++) {
-		//	printf("%02X ", uncom_data_buff[i]);
-		//}
-		//printf("\n");
+		printf("Decompressed Data:\n");
 
 		do {
-			for(int j = 0; j < 64; j++) {
+			for(int j = 0; j < 1020; j++) {
 				cur_idat_len = 0;
 				for(int i = 0; i < 4; i++) {
 					cur_idat_len += (file_data[offset+i] << (24-(8*i)));
 				}
 					//printf("%c", file_data[offset+cur_idat_len+8]);
 				if((j % 4) == 0) {
+					if(31 < file_data[offset+cur_idat_len+8] && file_data[offset+cur_idat_len+8] < 128) {
 						printf("%c", file_data[offset+cur_idat_len+8]);
+					} else {
+						offset = idat_byte_length;
+						break;
+					}
 				}
 				// Offset Plus idat length + 3 bytes
 				offset += cur_idat_len + 12;
 			}
+			printf("\n");
 		} while(offset < idat_byte_length);
 
 		free(idat_data);

include/crc_util.h

@@ -41,6 +41,7 @@ struct EMBED_THREAD_STRUCT {
 	unsigned int data_len;
 	size_t uncom_data_len;
 	size_t cur_offset;
+	size_t offset[8096];
 	size_t cur_iteration;
 	int width;
 	int color_range;

src/compress_util.c

@@ -82,6 +82,7 @@ void zlib_compress_data(unsigned char *data_chunk, size_t file_length, unsigned
         unsigned char out[CHUNK];
         int level = 9;
         int method = Z_DEFLATED;
+        //int windowBits = 15;
         int windowBits = 10;
         int memLevel = 9;
         //int strategy = Z_DEFAULT_STRATEGY;