From ddce9b2d44ab48fc566870c5155b39c8fc06f24d Mon Sep 17 00:00:00 2001
From: Benedict <benedict@0xb8000.de>
Date: Tue, 21 Feb 2017 12:52:02 +0100
Subject: moved files of set1 into subdir

---
 task6.c | 129 ----------------------------------------------------------------
 1 file changed, 129 deletions(-)
 delete mode 100644 task6.c

(limited to 'task6.c')

diff --git a/task6.c b/task6.c
deleted file mode 100644
index 949d0ec..0000000
--- a/task6.c
+++ /dev/null
@@ -1,129 +0,0 @@
-#include "lib.h"
-
-/**
- * split ciphertext in blocks of size blocksize
- * @return returns an array of string of size with blocksize elements
- */
-
-
-char **transpose_blocks(char *ciphertext, int blocksize, int length)
-{
-	char **blocks;
-	int i, j;
-	int number_blocks = length / blocksize;
-
-	blocks = malloc(blocksize*(sizeof(char*)));
-
-	for(i=0;i<blocksize;i++) {
-		blocks[i] = malloc(number_blocks+1);
-	}
-
-	for(j=0;j<blocksize;j++) {
-		for(i=0;i<number_blocks;i++) {
-			blocks[j][i] = ciphertext[(i*blocksize)+j];
-		}
-	}
-
-	return blocks;
-}
-
-int main()
-{
-	FILE *fp;
-	int keysize;
-	char ch;
-	char *file_content, *new_file_content, *chiphertext, *block1, *block2;
-	int file_size = 60, file_pos = 0;
-	int i; 
-	double min_hamming_distance, tmp;
-	
-	fp = fopen("6.txt", "r");
-
-	if (fp == NULL) {
-		printf("Error open file\n");
-		exit(1);
-	}
-	
-	file_content = malloc(file_size);
-
-	if (file_content == NULL) {
-		perror("out of memory");
-		exit(1);
-	}
-
-	// read data and decode it from base64
-	// result is not a hex strin or?
-
-	while ( (ch = fgetc(fp)) != EOF) {
-		// ignore new lines as this is part of base64
-		if (ch == '\n' || ch == '\r')
-			continue;
-
-		if (file_pos+1 >= file_size) {
-			new_file_content = realloc(file_content, (file_size+60));
-			if (new_file_content != NULL) {
-				file_content = new_file_content;
-				file_size += 60;
-			}
-			else {
-				printf("error allocating memory\n");
-				exit(1);
-			}
-		}
-		file_content[file_pos++] = ch;
-	}
-	file_content[file_pos] = '\0';
-
-	int ciphertext_len = 0;
-
-	chiphertext = malloc(file_pos+1);
-	ciphertext_len = decode_base64(file_content, chiphertext);
-
-	block1 = malloc(41);
-	block2 = malloc(41);
-
-	// max. hamming distacne is 100.
-	min_hamming_distance = 101;
-
-	int j=0;
-	// split ciphertext in 4 blocks of size 2 to 40
-	// and compute hamming distance of these blocks
-	for(i=2; i <= 40; i++) {
-		for(j=0;j< ciphertext_len/i;j++) {
-			memcpy(block1, &chiphertext[j], i);
-			block1[i+1] = '\0';
-			memcpy(block2, &chiphertext[j+i], i);
-			block2[i+1] = '\0';
-		
-			tmp += (double) hamming_distance_equal_length(block1, block2, i);
-		}
-		tmp = ((double)tmp / (double) (ciphertext_len/i)/ (double)i);
-		if (tmp <= min_hamming_distance) {
-			min_hamming_distance = tmp;
-			keysize = i;
-		}
-	}
-	
-	int number_blocks = ciphertext_len/keysize;
-	printf("use keysize: %i with hammind_distance: %f, number of blocks:%i\n", keysize, min_hamming_distance, number_blocks);
-	// split into keysize blcoks and transpose them 
-	char **transposed_blocks = transpose_blocks(chiphertext, keysize, ciphertext_len);
-
-	char key[keysize+1];
-	struct key_and_freq tmp_NOT_USED_HERE;
-
-	for(i=0;i<keysize;i++) {
-		key[i] = brute_force_single_byte_xor(transposed_blocks[i],
-					number_blocks, &tmp_NOT_USED_HERE);
-	}
-
-	key[keysize+1] = '\0';	
-	char *cleartext = malloc(ciphertext_len+1);
-	// xor with all single byte keys on the whole data
-	cleartext[ciphertext_len] = '\0';
-	xor_string(chiphertext, key, cleartext, keysize, ciphertext_len);
-
-	printf("%s\n", cleartext);
-	printf("used key: %s\n", key);
-	return 0;
-}
-- 
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