Re: tamper resistant messages on 8051

eugene wrote:
I need to send short RF messages (approx: 2 bytes) between 8051
devices. How do I make sure that the messages are not tampered and that
the message really came from the device?

I was thinking of using CMAC AES. But found out that AES isn't
efficient on 8051.

How do I generate untamperable messages in 8051?

Regardless of the CPU, you are looking at "message authentication" (aka "signing"). It's usually done by taking some cryptographic function of the message, & sending that along with it.
The first thing you need to determine is, what level of threat do you face? A bored student filling in a rainy night, or a major government agency which *really* wants to hack your system? A large spectrum in between. Where you are on it, determines how much security (read, CPU cycles) you need to provide.
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