Implementation of crc16 (CRC-16-CCITT) in python

crc16.py

def crc16(data: bytes, poly=0x8408):
    '''
    CRC-16-CCITT Algorithm
    '''
    data = bytearray(data)
    crc = 0xFFFF
    for b in data:
        cur_byte = 0xFF & b
        for _ in range(0, 8):
            if (crc & 0x0001) ^ (cur_byte & 0x0001):
                crc = (crc >> 1) ^ poly
            else:
                crc >>= 1
            cur_byte >>= 1
    crc = (~crc & 0xFFFF)
    crc = (crc << 8) | ((crc >> 8) & 0xFF)
    
    return crc & 0xFFFF

fromhex won't work if you're using upython? You could try import binascii bits_string = ''.join(str(bit) for bit in input_list) int_value = int(bits_string, 2) hex = hex(int_value)[2:] hex_value = binascii.unhexlify(hex)

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On Thu, 27 Apr 2023 at 19:03, TrajcheKrstev ***@***.***> wrote: ***@***.**** commented on this gist. ------------------------------ return('{:04X}'.format(crc)) Thanks, it works. Is there a better way to convert the list to be in a suitable format than this ChatGPT suggestion? bits_string = ''.join(str(bit) for bit in input_list) int_value = int(bits_string, 2) hex_value = hex(int_value) hex_string = hex_value.replace('0x', '0x0') if len(hex_value) % 2 == 1 else hex_value hex_value = bytes.fromhex(hex_string[2:]) crc=crc16(hex_value) — Reply to this email directly, view it on GitHub <https://gist.github.com/oysstu/68072c44c02879a2abf94ef350d1c7c6#gistcomment-4550238> or unsubscribe <https://github.com/notifications/unsubscribe-auth/AV562M34PM55UV4Y3T4S5PTXDIY53BFKMF2HI4TJMJ2XIZLTSKBKK5TBNR2WLJDHNFZXJJDOMFWWLK3UNBZGKYLEL52HS4DFQKSXMYLMOVS2I5DSOVS2I3TBNVS3W5DIOJSWCZC7OBQXE5DJMNUXAYLOORPWCY3UNF3GS5DZVRZXKYTKMVRXIX3UPFYGLK2HNFZXIQ3PNVWWK3TUUZ2G64DJMNZZDAVEOR4XAZNEM5UXG5FFOZQWY5LFVAZTOMRWGU4DSOFHORZGSZ3HMVZKMY3SMVQXIZI> . You are receiving this email because you commented on the thread. Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub> .

@pragma31 if I have a payload like this : " 623e0200000000000000000000000000" where 623e is crc given by a software i want to verify it , so what should i pass to get this value to the function that you have written here crc16 , thanks
same if i want to use https://crccalc.com/

@oysstu could you please guide me how could I use this code.
My data is (hex) E3BCBEBEA65EB3B87266124B2B238B6B
Polynomial is 0x1021