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90 lines
2.5 KiB
90 lines
2.5 KiB
#include <stdint.h> /* Funktionsbibliothek: Integer */
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#include <stdlib.h> /* Funktionsbibliothek: Hilfsfunktionen */
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#include <stdio.h> /* Funktionsbibliothek: Standard Ein- Ausgabe */
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#include "main.h"
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#include "encrypt.h"
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// disable deprecated warning
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#pragma warning(disable : 4996)
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void encipher(uint32_t num_cycles, uint32_t v[2], uint32_t const k[4])
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{
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unsigned int i;
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const uint32_t delta = 0x9E3779B9; // decipher changes:
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uint32_t v0 = v[0], v1 = v[1], sum = 0; // sum = delta * num_cycles;
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for (i = 0; i < num_cycles; i++)
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{
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v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]); //-=
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sum += delta; //-=, exchange lines above and below
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v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum >> 11) & 3]); //-=
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}
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v[0] = v0;
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v[1] = v1;
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}
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int encrypt(char *LoadFName, char *SaveFName, uint32_t key[4])
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{
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int ErrorCode = NO_ERROR; /* Error-Code-Variable */
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FILE *LoadFile; /* File welches geladen wird */
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FILE *SaveFile; /* File welches gespeichert wird */
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char block[2] = {0};
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uint32_t block_uint32[2] = {0};
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uint32_t num_cycles = 16;
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/* Kontrolliertes oeffnen der Files */
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if ((LoadFile = fopen(LoadFName, "rb")) == NULL)
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ErrorCode = ERROR_OPEN_LOAD_FILE;
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if ((SaveFile = fopen(SaveFName, "wb")) == NULL)
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ErrorCode = ERROR_OPEN_SAVE_FILE;
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/* Alle Filezugriffe moeglich ? */
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if (ErrorCode == NO_ERROR)
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{
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do
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{
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// reset vars
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block[0] = 0;
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block[1] = 0;
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block_uint32[0] = 0;
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block_uint32[1] = 0;
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block[0] = fgetc(LoadFile);
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// if eof => quit
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if(block[0] == EOF)
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{
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break;
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}
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block[1] = fgetc(LoadFile);
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// if eof => replace with space to get previous character within encryption
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if(block[1] == EOF)
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{
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block[1] = ' ';
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}
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// convert
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block_uint32[0] = (uint32_t)block[0];
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block_uint32[1] = (uint32_t)block[1];
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encipher(num_cycles, block_uint32, key);
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// write encrypted block to file
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int x = 0;
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while (x < 2)
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{
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fprintf(SaveFile, "%u ", block_uint32[x]);
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x++;
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}
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} while (!feof(LoadFile));
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}
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/* Wenn Orignalfile geoffnet werden konnte */
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if (ErrorCode != ERROR_OPEN_LOAD_FILE)
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fclose(LoadFile);
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/* Wenn Ausgabefile geschrieben werden konnte */
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if (ErrorCode != ERROR_OPEN_SAVE_FILE)
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fclose(SaveFile);
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return (ErrorCode); /* Rueckgabe des Fehlercodes */
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}
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