A weblog focused on interesting circuits, ideas, schematics and other information about microelectronics and microcontrollers.
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Because I have not tested all electronic circuits mentioned on this pages, I cannot attest to their accuracy; therefore, I do not provide a warranty of any kind and cannot be held responsible in any manner.
Two algorithms for an AVR
If you need to protect your data, here is two things you'll need: The CRC algorithm and the Rijndael (AES) cipher.
CRC is a well-known method to compute a good enough checksum. See more about CRC. If you need to protect your data and its integrity, you can use the CRC algorithm, you can find here: How to calculate a CRC in AVR assembly language.
If you have to encrypt your data with strong cipher, you can use the AES (Rijndael) algorithm. Here is an AVR assembly implementation of this block cipher. The implementation given here is optimized for speed (versus codesize), and achieves an encryption rate of more than 100 kByte per second (on a 16MHz MCU). The decryption performs about 40% slower than encryption (typical for Rijndael). The implemented algorithm is restricted to block and key sizes of 128 bit. Rijndael (AES) on AVR
More about AES on AVR