3ds_titlekey_crypt.c

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

#include <openssl/aes.h>

void chartohex(unsigned char* input, unsigned char* output)
{
	char tmp[3];
	memset(tmp, 0, 3);
	for (int i = 0; i < strlen(input); i++)
	{
		memcpy(tmp, &input[i * 2], 2);
		output[i] = (char)(strtol(tmp, NULL, 16));
	}
}

int encrypt_titlekey(unsigned char* titleId, unsigned char *titlekey, unsigned char *commonKey)
{
	AES_KEY aeskey_dec;
	unsigned char iv[16];

	int ret = 0;
	memset(iv, 0, 16);
	memcpy(iv, titleId, 8);

	ret = AES_set_encrypt_key(commonKey, 128, &aeskey_dec);
	if(ret<0)
	{
		printf("Failed to set key: %d\n", ret);
		return ret;
	}

	AES_cbc_encrypt(titlekey, titlekey, 16, &aeskey_dec, iv, AES_ENCRYPT);

	return 0;
}

int tikdecrypt_titlekey(unsigned char *titleId, unsigned char *titlekey, unsigned char* commonKey)
{
	// Convert the passed in values to binary arrays
	unsigned char titleIdData[0x08];
	unsigned char titleKeydata[0x10];
	unsigned char commonKeyData[0x10];
	chartohex(titleId, titleIdData);
	chartohex(titlekey, titleKeydata);
	chartohex(commonKey, commonKeyData);

	unsigned char encryptedTitlekey[0x10];
	memcpy(encryptedTitlekey, titleKeydata, 0x10);

	int ret = encrypt_titlekey(titleIdData, encryptedTitlekey, commonKeyData);
	if (ret)
	{
		return ret;
	}

	printf("\nDecrypted titlekey: ");
	for(int i=0; i<16; i++)printf("%02x", titleKeydata[i]);
	printf("\n");

	printf("Encrypted titlekey: ");
	for(int i=0; i<16; i++)printf("%02x", encryptedTitlekey[i]);
	printf("\n");

	return 0;
}

int main(int argc, char *argv[])
{
	printf("Title key encrypter by Drakia\n");

	if(argc != 4)
	{
		printf("Decrypt an encrypted titlekey\n");
		printf("%s <titleId> <decTitleKey> <0x3D Normal Key>\n\n", argv[0]);
		return 0;
	}

	if (strlen(argv[1]) != 16)
	{
		printf("Invalid title ID length\n\n");
		return 0;
	}

	if (strlen(argv[2]) != 32)
	{
		printf("Invalid title key length\n\n");
		return 0;
	}

	if (strlen(argv[3]) != 32)
	{
		printf("Invalid normal key length\n\n");
		return 0;
	}

	tikdecrypt_titlekey(argv[1], argv[2], argv[3]);
}