| ??? 05/04/05 15:36 Read: times |
#92895 - it's easy Responding to: ???'s previous message |
Erik Malund said: Of course not. I just use "winter diesel" when the outer temeprature gets below 0°C.
But you can not pour gas in a diesel engine. Erik Malund said: If the whole user program has to be reprogrammed, simply convert to binary, make the encryption and convert back to hex. Hex2bin2hex utilities laying around in piles.
1) make something that massages the .hex file without changing the control and address portion of the records.
But making it working directly on the hexfile is really a piece of cake... Erik Malund said: The bootloader has to be only modified in one and only place - where the program gets burned, the decryption routine has to be inserted. Oh yes, and the CRC and readback routines have to be cut out (or, the kosher solution is to make the encryption too, but I don't feel there is any real reason to do it).
2) make a modified ISP to be loaded into the ISPsection of the flash that echo to FlashMagic exactly the same way an unmodified ISP would. Erik Malund said:
and it is all for naught .... Please, believe me, there are reasons to do it and there is really no point discussing it further. Erik Malund said: Well that would be a really bad move from Philips to allow this... Please note that the LPC9xx's have separate lockbits for each sector, so it should be enough to fully protect the sectors the bootloader occupies.
Now if someone erase the program memory, leaving the ISP section the security bits are gone (I hope - if not so, "regular" programming would be a nightmare) so anyone can read the modified ISP and deduct the scrambling algorithm. Jan Waclawek |
| Topic | Author | Date |
| ISP-AES(or other tiny encryption)for LPC | 01/01/70 00:00 | |
| so it works? | 01/01/70 00:00 | |
| re so it works? | 01/01/70 00:00 | |
| could it be | 01/01/70 00:00 | |
| TEA | 01/01/70 00:00 | |
| re could it be? | 01/01/70 00:00 | |
| double-xor | 01/01/70 00:00 | |
| LPC935 | 01/01/70 00:00 | |
| TEA | 01/01/70 00:00 | |
| Tea time! | 01/01/70 00:00 | |
| TEA time ;) | 01/01/70 00:00 | |
More tea | 01/01/70 00:00 | |
| Please clarify requirements | 01/01/70 00:00 | |
| what i want, Dan | 01/01/70 00:00 | |
| Looks like you are set then | 01/01/70 00:00 | |
| to Dan | 01/01/70 00:00 | |
| Re: to Dan | 01/01/70 00:00 | |
| Mode of operation | 01/01/70 00:00 | |
| I underdstand now., thanks | 01/01/70 00:00 | |
| better done in hardware | 01/01/70 00:00 | |
| what about this? | 01/01/70 00:00 | |
| what are you making | 01/01/70 00:00 | |
| theft has to be prevented | 01/01/70 00:00 | |
| either or | 01/01/70 00:00 | |
| FM is just a "vehicle"... | 01/01/70 00:00 | |
| but a diesel | 01/01/70 00:00 | |
| it's easy | 01/01/70 00:00 | |
| again, why | 01/01/70 00:00 | |
| unsecure? | 01/01/70 00:00 | |
| yes | 01/01/70 00:00 | |
| Individual sector security bits removal | 01/01/70 00:00 | |
| lockbits | 01/01/70 00:00 | |
| Now i understand! | 01/01/70 00:00 | |
| same thing | 01/01/70 00:00 | |
| what am i making? | 01/01/70 00:00 | |
| be careful | 01/01/70 00:00 | |
| why GSM? | 01/01/70 00:00 | |
| FM | 01/01/70 00:00 | |
| FM | 01/01/70 00:00 | |
| for the xor method to work | 01/01/70 00:00 | |
| RC4 | 01/01/70 00:00 | |
| RC4 | 01/01/70 00:00 | |
| A reminder | 01/01/70 00:00 | |
| encryption | 01/01/70 00:00 | |
| pgpi.org | 01/01/70 00:00 | |
| ok thanks jez | 01/01/70 00:00 |