response = base64_enc(challenge+" "+CRC32(challenge)) use crc poly=0x04C11DB7 and print as decimal number https://www.crccalc.com/?crc=JSYCBPFOWSSKPK&method=CRC-32/ISO-HDLC&datatype=ascii&outtype=dec "JSYCBPFOWSSKPK 1029423621" || vv "SlNZQ0JQRk9XU1NLUEsgMTAyOTQyMzYyMQ=="