Best embedded processor for data encryption

[AndrewM]

As the titles states, I'm looking for opinions on the best mcu or embedded processor for handling data encryption and decryption.  I know from PC experience that it can be very processor intensive (mathematically).  Anyone have any experience on the mcu level with this type of thing?

[coldkryten]

Can you give a more detailed idea of what you're trying to do?  There are lots of types of encryption depending on what the goal is.  AES encryption can be pretty easily implemented on any 8-bit microcontroller.  (Plus, if you're ambitious and are not that concerned with security, you can program it yourself!)  Or are you looking for something higher performance and dealing with a 32-bit microprocessor?

[emmannuel]

Yeah there are lot of details that you need to mention to get the reply you want.

Cause the best processor for data encryption would be one that has hardware support for that encryption.  Which you didn't mention.

[AndrewM]

I'm shooting for encryption and decryption of an analog signal (voice), which means it would need to be pretty fast to avoid lag.  I figured conversion to digital, encrypt, transmit, decrypt, convert back to analog.  I found this for SHA hardware encryption/decryption:  http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2822/t/al

[coldkryten]

So assuming you are just sending voice you can get away with 8-bit sampling at 8kHz or so.  Better quality will likely require external ADCs and get 16-bit 16-20kHz or something similar.  Assuming the low figures, you need a processor capable of encrypting/decrypting data at roughly 62 kilobits/second and sending/receiving this data, as well as the ADC/DAC process.

The big question is why is this being encrypted?  If it's basically just for the hell of it, you could use a fast-ish AVR or PIC type processor and run a simplified stream cypher on it - I don't think? you could run full TEA or RC4 on something like that, but you could do an approximation. 

The simplest microcontroller I'm aware of that has hardware encryption support is the Atmel SAM7XC - quite a step up from 8-bit controllers but not impossible for the casual user to deal with since it doesn't need external memory etc...  They have hardware AES and 3-DES blocks, and support DMA so you could probably encrypt CD-quality audio and manage to do some other stuff at the same time on one of those.