Implementing byte stream cipher

Hi all,

I am proficient programming microcontrollers, and I want to implement
some form of stream cipher for encrypting serial communications.

What I would like to do is have two serial ports connected to one chip,
and then have plaintext on one port and ciphertext on the other. It
need not be 1bit encryption, an octet at a time will do. Another chip
would be doing decryption.

I can have a symmetrical key hidden in the chip and it would be
impossible to extract it. I have considered using TEA, but how can I go
from block to stream? I understand this may be extremely basic, so
pointing to resources is appreciated, too.

I am considering TEA as I would like to use the smallest
microcontroller possible (maybe 128 bytes of RAM will do? otherwise I
have to go to 1K) (Thinking AVR Tiny2313 or MEGA8 for those who know
them)

Thanks to all,

Hugo

.

Relevant Pages

  • Re: Implementing byte stream cipher
    ... I am proficient programming microcontrollers, ... some form of stream cipher for encrypting serial communications. ...
    (sci.crypt)
  • Re: Implementing byte stream cipher
    ... I am proficient programming microcontrollers, ... some form of stream cipher for encrypting serial communications. ... What I would like to do is have two serial ports connected to one chip, ...
    (sci.crypt)