SweeCrypt-c

A basic and fun cipher module for everyone. It converts regular text into symbols on a keyboard, kind of like a cipher. This is only for fun, using this module for cybersecurity is NOT ADVISED

This is a port of SweeCrypt-py to C.

This only relies on the standard library, it compiles with musl, so it might as well with glibc.

Currently, I'm still learning C, so this implementation may be a bit unstable, this is the first ever project I made in C.

If you get segfaults from this implementation, PLEASE REPORT A BUG! show your code snippet or CLI call in the issue.

Known to work on

• Linux
  • Using gcc, tcc, and clang
  • Known to work with glibc and musl
• FreeBSD
  • Using gcc and clang
• Haiku
  • Using gcc
  • Headers are installed separately, pkgman install haiku_devel
  • Cannot statically link properly
  • Add WHERE="/Haiku/system/non-packaged" when using make install
• Windows
  • Via MSYS2 using gcc and clang
  • Library and test can compile with MSVC, but CLI won't compile because Windows isn't POSIX and doesn't include unistd.h

Compiling

Library

$ cd lib
$ make
$ make test # optional
# make install # optional

This compiles both a shared object and static library

CLI

Make sure you compiled the library first

$ cd cli
$ make
# make install # optional

You can also statically link so you don't need to have libsweecrypt.so installed, but you'll probably make some nerds yell at you and/or begin an argument on the IRC channel you shared it on.

$ make LDFLAGS="-lsweecrypt -static"

Or only statically link SweeCrypt

$ make LDFLAGS="-Wl,-Bstatic -lsweecrypt -Wl,-Bdynamic"

Usage

CLI help

$ sweecrypt --help
SweeCrypt-c v1.1.1 - https://git.swee.codes/swee/SweeCrypt-c
An easy and fun encryption module and app
Copyright 2024-2026 Swee
This software is licensed with MIT license

Usage: sweecrypt [encrypt|decrypt] (--shift <n>) <msg>

Commands
    encrypt [str] Encodes a message from stdin or parameter
    decrypt [str] Decodes a message from stdin or parameter

Flags
    --help        Shows this message
    --shift <int> Specifies a database shift

Notes about C API

Although this C API is more cursed than the other implementations, it's still quite simple to use.

These examples are valid, compilable C programs.

#include <stdio.h>
#include "sweecrypt.h"

int main() {
    // Input
    char text[] = "hello, world!";
    // Buffer
    char buf[14]; // Length should be equal to the length of the input including \0
    // Sweecrypting
    size_t size = sweecrypt_encrypt(text, buf, 14, 0);
    //                              ^     ^    ^   ^
    //                            input   |    |  shift
    //                          result buffer  |
    //                                      size of result buffer
    if (size) {
        printf("%s\n", buf);
    } else {
        printf("Failed to encode\n")
    }
    return 0;
}

Tip

Although the functions return the final buffer's size, you can just call the function without defining a variable for it, but it's usually a good idea to use the returned value for error handling
SweeCrypt will return 0 if either no characters are in db, or the buffer size is less than the input length (including \0)

Make sure to include -lsweecrypt when compiling.

Encode

#include <stdio.h>
#include "sweecrypt.h"
 
int main() {
    char text[] = "hello, world!";
    char buf[14];
    sweecrypt_encrypt(text, buf, 14, 0);
    printf("%s\n", buf);
    return 0;
}

$ sweecrypt encrypt "hello, world!"
!?~~(:,}(>~/a

Decode

#include <stdio.h>
#include "sweecrypt.h"
 
int main() {
    char text[] = "!?~~(:,}(>~/a";
    char buf[14];
    sweecrypt_decrypt(text, buf, 14, 0);
    printf("%s\n", buf);
    return 0;
}

$ sweecrypt decrypt '!?~~(:,}(>~/a'
hello, world!

Shifting DB

#include <stdio.h>
#include "sweecrypt.h"
 
int main() { 
    // Encode
    char text[] = "hello, world!";
    char enc[14];
    sweecrypt_encrypt(text, enc, 14, 3);
    printf("%s\n", enc);
    // Correct output (dec_correct will match text)
    char dec_correct[14];
    sweecrypt_decrypt(enc, dec_correct, 14, 3);
    printf("%s\n", dec_correct);
    // Incorrect output (Nonsense string)
    char dec_wrong[14];
    sweecrypt_decrypt(enc, dec_wrong, 14, 0);
    printf("%s\n", dec_wrong);
    return 0;
}

$ sweecrypt encrypt --shift 3 "hello, world"
\!((>ba_>](#
$ sweecrypt decrypt --shift 3 "\!((>ba_>](#"
hello, world
$ sweecrypt decrypt "\!((>ba_>](#"
khoor?!zruog