Most littleweight Cryptography for PIC16F88

[gorkin]

Hello brothers!
Anyone know what the most littleweight cryptography method (algorithm)? Medium security are desire, but my microcontroller (PIC16F88) not have RAM or Flash resources...

Thanks in advance, Gorkin.

 

[C-Man]

It all depends on what needs to be done.

Can you specify what you want to do please?

best regards

 

[jonw0224]

I'm guessing you want to send a serial stream and it look like garbage. This is just a suggestion and doesn't offer much in the way of security but you could just define a map for each byte to another byte by a mathematical operation.

For example you could:

xor with some constant
swap a few bits

This wouldn't provide much protection, but people couldn't read the ascii stream.

People could however, watch the stream and observe frequencies of certain bytes and guess your map easily. If they used brute force, there aren't that many maps possible on only 8 bits.

It would be very easy to code.

 

[anddid]

i think the most lightweight with good enough security is TEA and its variants. **broken link removed** . It's actually very easy to implement in C on a 8bit micro.

 

[gorkin]

I need send 64 or 128 bytes package throught GPRS TCP conexion...I read about the TEA cyphering...very nice, I will write now my C code and next I will re-write it in assembly for my PIC16F88 microcontroller.

Thanks brothers!