The Stanley Parable: Ultra Deluxe save file (de/en)cryptor. https://drinkybird.net/files/misc/tspuddec.exe

tspuddec.c

// To use, pass the input file and output file
// e.g.: tspuddec.exe "C:\Users\Sean\AppData\LocalLow\Crows Crows Crows\The Stanley Parable_ Ultra Deluxe\tspud-savedata.txt" data.json
// The algorithm is a simple XOR and works both ways, so you can swap the parameters to encrypt again.
// The save file is a JSON file, which then contains JSON data as a string. Fun to edit...

#include <stdio.h>
#include <string.h>

static const char *ENCRYPTION_KEY = "saRpmZ6mMgZpmcojUkvkyGEQGez9YkWoXZfJdRc9ZmmJrCzfM8JksVxQfQK8uBBs";

int main(int argc, char *argv[]) {
	if (argc < 3) {
		printf("Usage: %s <input file> <output file>\n", argv[0]);
		return 1;
	}
	
	FILE *input = fopen(argv[1], "rb");
	if (input == NULL) {
		printf("Failed to open input file %s\n", argv[1]);
	}
	
	FILE *output = fopen(argv[2], "wb");
	if (output == NULL) {
		printf("Failed to open output file %s\n", argv[2]);
	}
	
	size_t i = 0;
	while (1) {
		char b;
		if (fread(&b, sizeof(char), 1, input) != 1) break;
		b ^= ENCRYPTION_KEY[i % strlen(ENCRYPTION_KEY)];
		fwrite(&b, sizeof(char), 1, output);
		
		i++;
	}
	
	fclose(output);
	fclose(input);
	
	return 0;
}