#include <stdio.h>
#include <openssl/aes.h>

int main(int argc, char *argv[]) {
	// Seems to come from section at 0x1cf700 in NOR.
	// More work needs to be done to figure out how it is decrypted
	const unsigned char key[] = {0x03, 0xBF, 0x2A, 0xE2, 0xE4, 0x6B, 0x63, 0x9B, 0xB8, 0xC0, 0x39, 0x71, 0x69, 0xD4, 0xB1, 0x5C,
	                             0x51, 0xD3, 0x39, 0xB9, 0x1D, 0x9C, 0xCE, 0x88, 0xBB, 0x46, 0x8F, 0x43, 0x6E, 0xCF, 0x8E, 0x4B};
//	0x35, 0x24, 0x79, 0xec, 0xce, 0xf2, 0xf1, 0xe8, 0x58, 0x8e, 0x93, 0x5c, 0x26, 0xc3, 0xa1, 0x15,
//				     0x2b, 0x43, 0x3f, 0x86, 0xbd, 0x1e, 0xd3, 0x15, 0xcc, 0x1c, 0xed, 0x16, 0xc4, 0x67, 0x5c, 0xa2};
	AES_KEY aesk;
	unsigned char in[16], out[16];
	int i;

	AES_set_decrypt_key(key, sizeof(key)*8, &aesk);

	if(argc < 2) {
		printf("%s nor_flash.bin", argv[0]);
		return -1;
	}

	FILE *fd = fopen(argv[1], "rb");

	if(fd == 0) {
		printf("Failed to open %s\n", argv[1]);
		return -1;
	}

#if 0
	fseek(fd, 0x100c9, SEEK_SET);
	fread(in, 1, 4, fd);
	fseek(fd, 0x100d3+0x80, SEEK_SET);

	unsigned int fw_size = (in[0]) | (in[1]<<8) | (in[2]<<16) | (in[3]<<24);
	fw_size -= 1;

	FILE *fd_out = fopen("decrypted_kernel.bin", "wb");
#else
	fseek(fd, 0x89, SEEK_SET);
	fread(in, 1, 4, fd);
	fseek(fd, 0x93+0x80, SEEK_SET);

	unsigned int fw_size = (in[0]) | (in[1]<<8) | (in[2]<<16) | (in[3]<<24);

	FILE *fd_out = fopen("decrypted_ota.bin.gz", "wb");
#endif

	// fw_size += 0x80;
	printf("Firmware size %x\n", fw_size);
	// for(i=0; i<fw_size; i+=16) {
	for(i=0; i<=fw_size-16; i+=16) {
		fread(in, 1, sizeof(in), fd);
		AES_decrypt(in, out, &aesk);
		if(i+16 <= fw_size)
			fwrite(out, 1, 16, fd_out);
		else
			fwrite(out, 1, fw_size-i, fd_out);
	}
	
        if (i < fw_size) {
           fread(in, 1, fw_size-i, fd);
           fwrite(in, 1, fw_size-i, fd_out);
           }
	fclose(fd);
	fclose(fd_out);
	return 0;
}