How to send block of 16 bytes fr PC serially?

[ganavel9783]

hi guys,

i'm working on a project to encrypt text files from PC using PIC16f877.the encryption algorithm i'm using is AES.the encryption algorithm code for the PIC is implemented to work with block of 16 bytes of data.so i need to send continous block of 16 bytes of data to be encrypted and sent back to PC to display the cipher text.

I do realise that i need to implement buffers to transmit and receive 16 bytes blocks of data to be encrypted by the PIC.

1) So do i need to use buffers as well from the PC side to send continous blocks of 16 bytes serially to the PIC? (I'm using Visual C++ on the PC side.)
2) How do i implement this task?
3) Any code examples?

Regards,
ganavel9783

 

[Davood Amerion]

You must embed that block with some extra bytes.
And make a block which include start byte, size byte(if size is fixed not reuaierd), command ,
16 bytes data block (if any), and CRC (or check sum) bytes (2byte).
Somthing like that HDLC protocol.

Regards,
Davood.

 

[ganavel9783]

Hi Davood,

Thanks for ur reply.However Davood i still need more explanation regarding how can i implement the method u suggested??Do u mind giving me some more hints?

 

[Davood Amerion]

you can download IC MT8952 (MITEL or ZARLINK company) which is HDLC controller and read its description.
Then get its idea to implement it with RS232 serial port, with simpler algorithm.
for example: insted of CRC you can use checksum

its link :
**broken link removed**