qistoph / arduinoaes256 Goto Github PK

Hi, is there some data available about the memory usage of this nice code?
Perhaps I want to use it on an ATmega328p with 32k flash and 2k RAM.
Thanks in advance, Karl

The library works great on a single processor. However if you encrypt the same string with the same keys, each processor (a duo and a pro mini), will generate a slightly different encrypted data array.

Is there something I am missing, or can do in order to "sync" the encription/ decription across multiple processors on a i2c bus?

Hi, when i try the example code it gives me this. The encrypted data is not normal, and more than 32byte because of the FFFFFF's. What are they ? I couldn't understand the problem. When i tried to write bytes one by one ( by doing a for loop ) i didn't get them.

Initializing AES256... 
Key: 
000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F
Unencrypted data: 
61736466617364666173646661736466
Encrypted data: 
024117FFFFFFFD2E737145582CFFFFFF976F47FFFFFFBEFFFFFFDA20
Back decrypted data: 
61736466617364666173646661736466

If I change the data in the examples to 32 bytes, for instance:

uint8_t data[] = {
    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
    0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
    0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F
};

the output on the serial monitor is:

Key: 
0001020304050607000102030405060700010203040506070001020304050607
Unencrypted data: 
000102030405060708090A0B0C0D0E0F000102030405060708090A0B0C0D0E0F
Encrypted data: 
7EE7EF984D51B1E3E1A31F8559988CF2000102030405060708090A0B0C0D0E0F
Back decrypted data: 
000102030405060708090A0B0C0D0E0F000102030405060708090A0B0C0D0E0F

As you can see, only the first 16 bytes are being encrypted (7EE7EF984D51B1E3E1A31F8559988CF2); the rest is still cleartext. Why is that?