Re: I have problem in AUTHENTICATION

[nimaltd]

hi again
Sorry for my English.

My current key is uint8_t key = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
when i change uint8_t key = {0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0};
AUTHENTICATION worked with no error.
when uint8_t key = {0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0};
AUTHENTICATION not worked


I have one other question .
How can I change key :-)

1 : first AUTHENTICATION with old key
2 : xor Old key and new key. [16 byte with 16 byte]
3 : calc crc16 . [ 2 byte ]
4 : set to zero next 6 byte buffer.
5 : Decrypt 24 byte with old key.
6 : add 0xc4 and 0x00 to first of block and send data

but not work.


my crc16 function is


uint16_t crc16(uint8_t * data_p, uint8_t length)
{
uint8_t x;
uint16_t crc = 0xFFFF;

while (length--){
x = crc >> 8 ^ *data_p++;
x ^= x>>4;
crc = (crc << 8) ^ ((unsigned short)(x << 12)) ^ ((unsigned short)(x <<5)) ^ ((unsigned short)x);
}
return crc;
}


thanks for your answer

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