My encryption in C

// discuss
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void flip(char *str) {
   
    int i = -1, o = strlen(str);
    char temp;
   
    while((--o - ++i) >= 0) {
        temp = str[i];
        str[i] = str[o];
        str[o] = temp;
    }
   
}

void rot(char *str, int number) {
   
    int i;
    number %= 26;
   
    for(i=0; i<strlen(str); i++)
       
        if(isupper(str[i])) {
        if(!isupper(str[i] += number))
            str[i] -= 26;
        }
       
        else if(islower(str[i])) {
            if(!islower(str[i] += number))
                str[i] -= 26;
        }
}

int encrypt(char *filepath, char *encrypted) {
   
    FILE *fp, *fp2;
    char *buffer;
    long filesize;
    int i = -1;
   
    if(!(fp = fopen(filepath, "rb"))) {
        fprintf(stderr, "Can't access %s\n", filepath);
        return 1;
    }
   
    if(!(fp2 = fopen(encrypted, "w"))) {
        fprintf(stderr, "Can't write to %s\n", encrypted);
        fclose(fp);
        return 2;
    }
   
    fseek(fp, 1, SEEK_END);
    filesize = ftell(fp);
    rewind(fp);

    buffer = (char*)malloc(filesize+1);
   
    fread(buffer, 1, filesize, fp);
    fclose(fp);
   
    while(buffer[++i])
        if(islower(buffer[i]))
            buffer[i] = 219 - buffer[i];
        else if(isupper(buffer[i]))
            buffer[i] = 155 - buffer[i];
        else if(isdigit(buffer[i]))
            buffer[i] = 105 - buffer[i];
       
    flip(buffer);
    rot(buffer, 13);
   
    fputs(buffer, fp2);
    free(buffer);
    fclose(fp2);
   
    return 0;
}

main(int argc, char **argv) {
    encrypt(argv[1], argv[2]);
}

// discuss
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int encrypt(char *filepath, char *encrypted) {
  
    FILE *fp, *fp2;
    char *buffer;
    long filesize;
    int i = -1;
    int x = -1;
  
    if(!(fp = fopen(filepath, "rb"))) {
        fprintf(stderr, "Can't access %s\n", filepath);
        return 1;
    }
  
    if(!(fp2 = fopen(encrypted, "w"))) {
        fprintf(stderr, "Can't write to %s\n", encrypted);
        fclose(fp);
        return 2;
    }
  
    fseek(fp, 1, SEEK_END);
    filesize = ftell(fp);
    rewind(fp);

    buffer = (char*)malloc(filesize+1);
    memset(buffer, 0, filesize+1);

    fread(buffer, 1, filesize, fp);
    fclose(fp);

    while(buffer[++i])
    {
        for(x = 0; x < (int)buffer[i]; x++)
            fputs("desu", fp2);
        fputs("^___^", fp2);
    }

    free(buffer);
    fclose(fp2);
  
    return 0;
}

main(int argc, char **argv) {
    encrypt(argv[1], argv[2]);
}

That's some remarkably shitty code you have there.

>>1
Hint: Implement DES

>>4
Stupid, I meant AES

>>5
Serpent is better.

>>6
MD5 is better

>>7
brokan

>>1
That kind of encryption is dead. The problem is, with that, you have the method of encryption on a computer, and the method of decrypting on your recipient's computer. They can be hacked. The programs can be reverse-engineered to get the method. Then your encryption is about as good as ROT-26.

Don't roll your own. Use AES, Twofish or some such algorithm that's had some actual research and is a proper standard. If you're really paranoid, use separate key material for both and encrypt twice.

AES is developed by people who are smarter than you and me, tested for more hours than you and I have in our lives, and used by people that sum more money than we can even imagine. If it's secure for them, it's secure for us. For massive damage, do what >>10 said; that way you could afford to have one of the two "broken" (more like weakened by mathematical analysis to find a quicker way to find your key or an equivalent key).

        temp = str[i];
        str[i] = str[o];
        str[o] = temp;

lol, only fags use temp variables when swapping data

        *str[i] ^= *str[o];
        *str[o] ^= *str[i];
        *str[i] ^= *str[o];

VROMM VROOM FAST AND LESS MEMORY BEXCAUSE IT DOEST USE VARIABLES OOPS CFLAGS JUIST KICKED IN IM OFF BYEEEEEEEEEEEEEE~~~~~~

All of you suck. If he wants to write his own encryption lib, fine, it'll help him get forward. Just using software without trying to write your own is what Myspace users do.

I hope >>12 is being facetious.

>>14
Would he have mentioned CFLAGS otherwise?

>>12
enjoy your overflow errors :D

>>12
You must use Gentoo Linux...

>>17
You can't tell me what to do!

>>16
wut?

>>16
enjoy your not understanding anything about anything :D

LISP

That is powerfull i   heard of python   Nor aware of   I stand pleasantly?

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