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#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <openssl/rand.h>
#include <unistd.h>
#include <errno.h>
#include <error.h>
void xor(int ed, char* mess, char* keyf, char* outp); /* operates the bitwise XOR between mess and keyf and puts the output to outp */
void keyrand(int nb, char* outp); /* generates random numbers using RAND_bytes from openssl and puts them into outp */
void help(char* av[]); /* prints the help message */
int main(int argc, char* argv[]) {
int opt = 1;
int command = 0;
int comm = 0;
char* message = NULL;
char* keyfile = NULL;
char* output = NULL;
int nbytes = -1; // must be resolved temporary workaround (ho sonno)
/* The following while cycle parses the argv vector to find commands, options and relative arguments
using the function getopt_long */
while (opt) {
int option_index = 0;
static struct option options[] = {
{"decrypt", required_argument, 0, 'd'},
{"encrypt", required_argument, 0, 'e'},
{"key-file", required_argument, 0, 'k'},
{"key-gen", no_argument, 0, 'g'},
{"help", no_argument, 0, 'h'},
{"nbytes", required_argument, 0, 'b'},
{"output", required_argument, 0, 'o'},
{0, 0, 0, 0},
};
if ((opt = getopt_long(argc, argv, "b:d:e:ghk:o:", options, &option_index)) == -1)
break;
switch (opt) {
case 'b':
nbytes = atoi(argv[optind-1]);
break;
case 'd':
message = argv[optind-1];
command++;
comm = 'd';
break;
case 'e':
message = argv[optind-1];
if (access(message, F_OK) == -1) { /* checks the existence of the file and eventually exits */
error(errno, errno, message);
}
command++;
comm = 'e';
break;
case 'g':
command++;
comm = 'g';
break;
case 'h':
help(argv);
command++;
break;
case 'k':
keyfile = argv[optind-1];
if (access(keyfile, F_OK) == -1) { /* look at the comment before */
error(errno, errno, keyfile);
}
break;
case 'o':
output = argv[optind-1];
break;
case '?':
break;
default:
printf("carachter code returned 0%o \n", opt);
}
}
/* Next section performs some input checks */
if (command == 0) {
printf("No command called \n");
exit(EXIT_FAILURE);
} else if (command > 1) {
printf("Multiple commands called \n");
printf("%s [COMMAND] [OPTIONS] ... \n",argv[0]);
exit(EXIT_FAILURE);
}
if (optind < argc) {
printf("Too many arguments \n");
exit(EXIT_FAILURE);
}
/* Next section detects the functions to call */
if (comm == 'e' || comm == 'd') {
if (keyfile == NULL) {
printf("No key specified: exit! \n");
exit(EXIT_FAILURE);
}
xor(comm, message, keyfile, output);
} else if (comm == 'g') {
keyrand(nbytes, output);
}
exit(EXIT_SUCCESS);
}
void xor(int ed, char* mess, char* keyf, char* outp) {
char* defenoutp = "critt";
char* defdeoutp = "decritt";
/* In absence of input by users nex block sets the default values */
if (outp == NULL) {
if (ed == 'e') {
printf("WARNING no output name specified using default value 'critt' \n");
outp = defenoutp;
} else if (ed == 'd') {
printf("WARNING no output name specified usign default value 'decritt' \n");
outp = defdeoutp;
}
}
FILE* mex = fopen(mess, "r");
FILE* keyx = fopen(keyf, "r");
FILE* critt = fopen(outp, "w");
int i = 1;
char a, b;
while(i != EOF) {
i = fscanf(mex, "%c", &a);
fscanf(keyx, "%c", &b);
if(i != EOF) {
fprintf(critt, "%c", a^b);
}
}
fclose(mex);
fclose(keyx);
fclose(critt);
if (ed == 'e') {
printf("Message successfully encrypted \n");
} else if (ed == 'd') {
printf("Message successfully decrypted \n");
}
return;
}
void keyrand(int nb, char* outp) {
char* defoutp = "default.key";
/* Next block controls the inputs and eventually sets the default values */
if((nb == -1) && (outp == NULL)) {
printf("WARNING no option specified usign default values... \n");
nb = 256;
outp = defoutp;
}
if (nb < -1) { // orribile
printf("Negative byte value inserted! \n");
printf("Exiting... \n");
exit(EXIT_FAILURE);
} else if (nb != 0) {
if(nb == -1) {
printf("No byte number specified... using default value: 256 \n");
nb = 256;
}
unsigned char key[nb];
RAND_bytes(key, nb);
if (outp == NULL) {
outp = defoutp;
printf("No output name specified... using default value: default.key \n");
}
FILE* file = fopen(outp, "w");
fwrite(key, sizeof(char), nb, file);
fclose(file);
printf("Created key file %s of %d bytes \n", outp, nb);
} else {
printf("Byte number specified is 0. \n");
printf("Doing nothing! \n");
}
return;
}
void help(char* av[]) {
printf("ONETIMEBLUH USAGE: \n");
printf("%s [COMMAND] [OPTIONS] \n \n", av[0]);
printf("COMMANDS: \n");
printf("-d, --decrypt=FILE decrypt message (input) same ad --encrypt, just for the feeling \n");
printf("-e, --encrypt=FILE encrypt message (input) \n");
printf("-h, --help print this help \n");
printf("-g, --key-gen create key file \n \n");
printf("OPTIONS \n");
printf("-k, --key-file=KEY_FILE use key (input) \n");
printf("-b, --nbytes=NUM number of bytes \n");
printf("-o, --output=FILE output name \n \n");
printf("Onetimebluh project repository at http://git.eigenlab.org/Seppia/onetimebluh \n");
return;
}
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