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-rw-r--r--lib.c473
1 files changed, 0 insertions, 473 deletions
diff --git a/lib.c b/lib.c
deleted file mode 100644
index c2ee753..0000000
--- a/lib.c
+++ /dev/null
@@ -1,473 +0,0 @@
-
-#include "lib.h"
-
-static const unsigned char base64_encode[] =
- "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
- "abcdefghijklmnopqrstuvwxyz"
- "0123456789+/";
-
-
-static const unsigned char hex_encode[] =
- "0123456789abcdef";
-
-
-
-/**
- * teset wheter a bit on the given position is 1
- */
-static int bit_on(char test, int bit)
-{
- char tmp;
- tmp = 1 << bit;
- tmp = test & tmp;
-
- return (int) tmp;
-}
-
-
-/**
- * returns true if the given string contains only printable or whitespace
- * characters
- */
-int isprintable(char *string, int length)
-{
- int i;
-
- for(i=0;i<length;i++) {
- if(!(isprint(string[i]) || isspace(string[i]))) {
- return 0;
- }
- }
-
- return 1;
-}
-
-
-/*
- * task the first three characters of encode and tranform it into the coresponding
- * for bytes in base64 and stores it in result
-*/
-static void three_bytes_to_base64(char * encode, int bytes_to_print, char *result)
-{
- unsigned char one, two, three, four;
- unsigned char tmp;
- char ret[4];
-
- // first six bits
- one = encode[0] >> 2;
- ret[0] = base64_encode[one];
- if(bytes_to_print-- > 0)
- result[0] = ret[0];
- // second six bits
- // two last bits of first byte
- tmp = encode[0] & 0x03;
- two = encode[1] >> 4;
- tmp = tmp << 4;
- two = tmp | two;
- ret[1] = base64_encode[two];
- if(bytes_to_print-- > 0)
- result[1] = ret[1];
- // second six bits
- // two last bits of first byte
- // third six bits
- tmp = encode[1] & 0x0F;
- tmp = tmp << 2;
- three = encode[2] & 0xC0;
- three = three >> 6;
- three = tmp | three;
- ret[2] = base64_encode[three];
- if(bytes_to_print-- > 0)
- result[2] = ret[2];
- // last six bit11s
- four = encode[2] & 0x3F;
- ret[3] = base64_encode[four];
- ret[4] = '\0';
- if(bytes_to_print-- > 0)
- result[3] = ret[3];
-}
-
-void print_char_bit(char print)
-{
- int i;
- for(i=0;i<8;i++) {
- if (bit_on(print,i))
- printf("1");
- else
- printf("0");
- }
-}
-/**
- * Transform four base64 encoded characters back to three bytes
- */
-
-const char decodeCharacterTable[256] = {
- -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
- ,-1,62,-1,-1,-1,63,52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-1,-1,-1,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21
- ,22,23,24,25,-1,-1,-1,-1,-1,-1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,-1,-1,-1,-1,-1,
- -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
- -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
- ,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
- -1,-1,-1
-};
-
-
-void decode_four_base64_byte(char *string1, char *result)
-{
- char buf[4];
-
- // map the bytes back to the orginial bitmap
- // A = 0
- buf[0] = decodeCharacterTable[(int)string1[0]];
- buf[1] = decodeCharacterTable[(int)string1[1]];
- buf[2] = decodeCharacterTable[(int)string1[2]];
- buf[3] = decodeCharacterTable[(int)string1[3]];
-
- // first byte is first six bits of base64 one and 2 bit of base64 second
- result[0] = ((buf[0] << 2) & 0xFC) | ((buf[1] >> 4) & 0x03);
-
- // second byte 4 bits of second base64 + 4 bits of third base64
- result[1] = ((buf[1] << 4) & 0xF0) | ((buf[2] >> 2) & 0x0F);
-
- // third byte 2 bits of third base54 + 6 bits of fourth base64
- result[2] = ((buf[2] & 0x03) << 6) | (buf[3] & 0x3F);
-
-}
-
-
-int decode_base64(char *string1, char *result)
-{
- int i, j, padding;
-
- for(i=0, j=0;i<strlen(string1);i += 4, j +=3) {
- decode_four_base64_byte(&string1[i], &result[j]);
- }
-
- // handle padding in the last four bytes
- i -= 4;
-
- for(padding=0;i<strlen(string1);i++) {
- if (string1[i] == '=')
- padding++;
- }
-
- result[j-padding] = '\0';
-
- return (j-padding);
-
-}
-
-static char string_to_hex_map[] = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
- 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D,
- 0x0E, 0x0F};
-/*
- * This function converts the first char of a string into its corresponding
- * hex value
- *
- * @return on Sucess return 0, if char is no valid hex value returns -1
- */
-static int hex_char_to_bit(char toEncode)
-{
- char encode;
- switch(toEncode) {
- case '0':
- encode = string_to_hex_map[0];
- break;
- case '1':
- encode = string_to_hex_map[1];
- break;
- case '2':
- encode = string_to_hex_map[2];
- break;
- case '3':
- encode = string_to_hex_map[3];
- break;
- case '4':
- encode = string_to_hex_map[4];
- break;
- case '5':
- encode = string_to_hex_map[5];
- break;
- case '6':
- encode = string_to_hex_map[6];
- break;
- case '7':
- encode = string_to_hex_map[7];
- break;
- case '8':
- encode = string_to_hex_map[8];
- break;
- case '9':
- encode = string_to_hex_map[9];
- break;
- case 'a':
- encode = string_to_hex_map[10];
- break;
- case 'b':
- encode = string_to_hex_map[11];
- break;
- case 'c':
- encode = string_to_hex_map[12];
- break;
- case 'd':
- encode = string_to_hex_map[13];
- break;
- case 'e':
- encode = string_to_hex_map[14];
- break;
- case 'f':
- encode = string_to_hex_map[15];
- break;
- default:
- return -1;
- }
-
- return encode;
-
-}
-
-/**
- * takes the first two hex characters of start and convert them to one byte
- * with the coressponding value of the two hex chars
- */
-static void two_char_hex(char *start, char *result)
-{
- char first = hex_char_to_bit(start[0]);
- char second = hex_char_to_bit(start[1]);
-
- *result = first;
- *result = *result << 4;
- *result = *result | second;
-}
-
-/**
- * xor agianst a key. if the length of key is less than the length of
- * str1 than the key will be repeated
- * @param str1 string which should be xored agianst the given key
- * @param key
- * @param result buffer where the result is stored
- */
-void xor_string(char *str1, char *key, char *result, int length_key, int length_str1)
-{
- int i, j;
- //int length_key = strlen(key);
-
- for(i=0, j=0;i<length_str1;i++,j++) {
- if (j >= length_key)
- j = 0;
-
- result[i] = str1[i] ^ key[j];
- }
-
- result[i] = '\0';
-}
-
-
-/**
- * transform the bytes in str1 into its correspond printable hex version
- * @param str1 binary strewam which should be converted
- * @param result buffer where the results should be stored
- * @param length legnth of str1
- */
-void hex_binary_to_string(char *str1, char *result, int length)
-{
- int i, j, tmp = 0;
-
- for(i=0,j=0;i<length;i++, j+=2) {
- tmp = str1[i] & 0xF0;
- tmp = tmp >> 4;
- result[j] = hex_encode[tmp];
- tmp = str1[i] & 0x0F;
- result[j+1] = hex_encode[tmp];
- }
-
- result[j] = '\0';
-}
-
-/**
- * takes a hex string and converts it to its correspond binary counterpart
- */
-int decode_hex_string(char *encode, char* result)
-{
- int i;
- int length = strlen(encode);
-
- for(i = 0;i< length/2;i++)
- two_char_hex(&encode[i*2], &result[i]);
-
- return i;
-}
-
-/**
- * counts the frequent characters in a string an divide the number through the
- * total number of characters
- * @param string string where the frequent characters should be counted
- * @param length length of string
- */
-
-static int frequent_histogramm_matchs(char *string, int length)
-{
- int i;
- int hits = 0;
- char tmp;
- int number_frequent_characters[14] = { 0, 0, 0, 0, 0, 0, 0, 0 ,0 ,0 ,0 ,0, 0, 0};
- // frequent characters:
- // a c d e h i l m n o r s t u w
- double standard_frequencies[14] = { 8.1, 2.7, 4.2, 12.7, 6.0, 6.9, 4.0, 2.4, 6.7, 7.5, 5.9, 6.3, 9.0, 2.7 };
-
- // count frequent characters
- for(i=0;i<length;i++) {
- tmp = tolower(string[i]);
- switch(tmp) {
- case 'a':
- number_frequent_characters[0]++;
- break;
- case 'c':
- number_frequent_characters[1]++;
- break;
- case 'd':
- number_frequent_characters[2]++;
- break;
- case 'e':
- number_frequent_characters[3]++;
- break;
- case 'h':
- number_frequent_characters[4]++;
- break;
- case 'i':
- number_frequent_characters[5]++;
- break;
- case 'l':
- number_frequent_characters[6]++;
- break;
- case 'm':
- number_frequent_characters[7]++;
- break;
- case 'n':
- number_frequent_characters[8]++;
- break;
- case 'o':
- number_frequent_characters[9]++;
- break;
- case 'r':
- number_frequent_characters[10]++;
- break;
- case 's':
- number_frequent_characters[11]++;
- break;
- case 't':
- number_frequent_characters[12]++;
- break;
- case 'u':
- number_frequent_characters[13]++;
- break;
- }
- }
- #define FREQ_AREA 0.7
- // compare frequncies with standard frequencies
- for(i=0;i<14;i++) {
- double freq =(double) ((double)number_frequent_characters[i]*100/(double)length);
- if((((standard_frequencies[i] * (1-FREQ_AREA) < freq)
- )&& ((standard_frequencies[i] * (1+FREQ_AREA)) > freq))) {
- hits++;
- }
- }
- return hits;
-}
-
-/**
- * encode the given string into base64 and stores it in result
- */
-
-void encode_to_base64(char *encode, char *result)
-{
- int length = strlen(encode);
-
- int rounds = length / 3;
- int bytes_last_round = length % 3;
- int i;
-
- for (i=0;i<rounds;i++) {
- three_bytes_to_base64(encode + i*3,4, &result[i*4]);
- }
- // in der letzen runde nicht mehr alle ausgeben
- // nur noch 3-leftover
- if (bytes_last_round > 0) {
- three_bytes_to_base64(encode + i*3, 1+bytes_last_round, &result[i*4]);
-
- for(i=0;i<(3-bytes_last_round);i++)
- result[i*4+(1+bytes_last_round)] = '=';
- }
-
-}
-
-/**
- * prints and base64 encoded string
- */
-void print_base64_string(char *string)
-{
- // after 76 charactes line break
-
-}
-
-/**
- * compute the hamming distance (number of different bits) of two string
- * @param string1 first string
- * @parma string2 second string
- * @return returns the hamming distance
- */
-int hamming_distance_equal_length(char *string1, char *string2, int length)
-{
- char tmp;
- int i, j;
- int hamming_distance = 0;
-
- for(i=0;i<length;i++) {
- tmp = string1[i] ^ string2[i];
- for(j = 0; j < 8; j++) {
- if (bit_on(tmp, j))
- hamming_distance++;
- }
- }
- return hamming_distance;
-}
-
-/**
- * test every byte on the string as key and returns the found keys
- */
-char brute_force_single_byte_xor(char *string, int length, struct key_and_freq *ret)
-{
- int i;
- char *xor_tmp;
- char single_byte_key;
- char key = 'A';
- int max_hits = 0;
- int tmp_hits = 0;
-
- xor_tmp = malloc(length+1);
-
-// printf("NEW STINGT TO BREAK\n");
- // test for every byte
- for(i=1;i<255;i++) {
- single_byte_key = (char) i;
- xor_string(string, &single_byte_key, xor_tmp, 1, length);
-
- // if string contains not printable characters it is not
- // the cleartext
- if (!isprintable(xor_tmp, length))
- continue;
-
- tmp_hits = frequent_histogramm_matchs(xor_tmp, length);
-
- if (tmp_hits > max_hits) {
- max_hits = tmp_hits;
- key = single_byte_key;
- //printf("Key: %c, hits: %i\n", key, max_hits);
- }
-
- }
-
- ret->key = key;
- ret->hits= max_hits;
-
- return key;
-}
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