Pokémon Battle Revolution basic encryption/decryption functions

functions.cpp

#define _CRT_SECURE_NO_WARNINGS
#define _SCL_SECURE_NO_WARNINGS

#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <cstdint>

using namespace std;

typedef uint8_t	 u8;
typedef uint16_t u16;
typedef uint32_t u32;

inline u16 read16(u8* buf) {
	return (buf[0] << 8) | buf[1];
}

inline void write16(u8* buf, u16 val) {
	buf[1] = (u8)val;
	buf[0] = (u8)(val >> 8);
}

inline u32 read32(u8* buf) {
	return (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
}


inline void write32(u8* buf, u32 val) {
	buf[3] = (u8)val;
	buf[2] = (u8)(val >> 8);
	buf[1] = (u8)(val >> 16);
	buf[0] = (u8)(val >> 24);
}


// THIS IS THE SAME ALGORITHM AS THE ONE USED IN Pokémon XD (with different boundaries)

inline void advanceKeys(u16 keys[4]) {
	u16 a = keys[0] + 0x43, b = keys[1] + 0x29, c = keys[2] + 0x17, d = keys[3] + 0x13;

	keys[0] = (a & 0xf) | ((b << 4) & 0xf0) | ((c << 8) & 0xf00) | ((d << 12) & 0xf000);
	keys[1] = ((a >> 4) & 0xf) | (b & 0xf0) | ((c << 4) & 0xf00) | ((d << 8) & 0xf000);
	keys[2] = (c & 0xf00) | ((b & 0xf00) >> 4) | ((a & 0xf00) >> 8) | ((d << 4) & 0xf000);
	keys[3] = ((a >> 12) & 0xf) | ((b >> 8) & 0xf0) | ((c >> 4) & 0xf00) | (d & 0xf000);
}

void decryptDataStructure(u8* in, u8* out, size_t size) {
	copy(in, in + 8, out);
	u16 keys[4] = { 0 };

	for (size_t i = 0; i < 4; ++i) keys[i] = read16(in + 2 * i);
	u16 tmp = 0;

	for (size_t i = 8; i < size; i += 8) {
		for (size_t j = 0; j < 4; ++j) {
			tmp = read16(in + i + 2 * j);
			tmp -= keys[j];
			write16(out + i + 2 * j, tmp);
		}
		advanceKeys(keys);
	}
}

void encryptDataStructure(u8* in, u8* out, size_t size) {
	copy(in, in + 8, out);
	u16 keys[4] = { 0 };

	for (size_t i = 0; i < 4; ++i) keys[i] = read16(in + 2 * i);
	u16 tmp = 0;

	for (size_t i = 8; i < size; i += 8) {
		for (size_t j = 0; j < 4; ++j) {
			tmp = read16(in + i + 2 * j);
			tmp += keys[j];
			write16(out + i + 2 * j, tmp);
		}
		advanceKeys(keys);
	}
}


bool checkDataChecksum(u8* data, size_t size, size_t checksumOffset = 8, bool fix = false) {
	// Decrypted save data
	u8* currentChecksum_addr = data + checksumOffset;

	u32 currentChecksum[16], checksum[16] = { 0 };
	for (size_t i = 0; i < 16; ++i) currentChecksum[i] = read32(currentChecksum_addr + 4 * i);
	
	u8 checksumBackup[64];

	copy(currentChecksum_addr, currentChecksum_addr + 64, checksumBackup);
	fill(currentChecksum_addr, currentChecksum_addr + 64, 0);

	for (size_t i = 0; i < size; i += 2) {
		u16 val = read16(data + i);
		for (size_t j = 0; j < 16; ++j)
			checksum[j] += (val >> j) & 1;
	}

	if (fix) {
		for (size_t i = 0; i < 16; ++i) write32(currentChecksum_addr + 4 * i, checksum[i]);
	}
	else {
		copy(checksumBackup, checksumBackup + 64, currentChecksum_addr);
	}

	return equal(checksum, checksum + 16, currentChecksum);
}

bool decryptSaveSlotAndCheckChecksums(u8* in, u8* out) { 
	decryptDataStructure(in, out, 0x1c0000);
	return checkDataChecksum(out, 0x1c0000, 0x1bff80) && checkDataChecksum(out, 0x100, 8); // end - 0x80
}

void encryptSaveSlotAndUpdateChecksums(u8* in, u8* out) {
	checkDataChecksum(in, 0x100, 8, true);
	checkDataChecksum(in, 0x1c0000, 0x1bff80, true); // end - 0x80
	encryptDataStructure(in, out, 0x1c0000);
}

bool decryptWiimoteTrainerCardAndCheckChecksum(u8* in, u8* out) {
	decryptDataStructure(in, out, 0x780);
	return checkDataChecksum(out, 0x780, 8);
}

void encryptWiimoteTrainerCardAndUpdateChecksum(u8* in, u8* out) {
	checkDataChecksum(in, 0x780, 8, true);
	encryptDataStructure(in, out, 0x780);
}

int main(void) {
	u8* buf = new u8[0x380000];
	u8* outBuf = new u8[0x380000];

	FILE *f = fopen("PbrSaveData", "rb");
	fread(buf, 1, 0x380000, f);
	fclose(f);

	for (size_t i = 0; i < 2; ++i) decryptSaveSlotAndCheckChecksums(buf + 0x1c0000*i, outBuf + 0x1c0000*i);

	FILE *of1 = fopen("PbrSaveData_decrypted_current", "wb+");
	FILE *of2 = fopen("PbrSaveData_decrypted_backup", "wb+");

	u32 saveCount1 = read32(outBuf + 0x4c), saveCount2 = read32(outBuf + 0x1c0000 + 0x4c);
	if (saveCount2 > saveCount1) swap(of1, of2);

	fwrite(outBuf, 1, 0x1c0000, of1);
	fwrite(outBuf + 0x1c0000, 1, 0x1c0000, of2);
	fclose(of1);
	fclose(of2);

	delete[] buf;
	delete[] outBuf;

	return 0;
}

I've decrypted my battle revolution save file using this code but how do I re-encrypt it so I can put it back into battle revolution after I've edited it with a hex editor?