Python CTR模式解密

谁来帮帮我。这是CTR模式解密，它应该打印字母，但它没有。这是解密公式。输入为十六进制值，输出应为字符/字母

def ctr_dec(ys):

  xs = [] 

  ss = ["10101000", "10101001", "10101010", "10101011", "10101100", "10101101"]

  key = int("0X08", 16)

  for i in range(len(ys)):

    #163*(block-key+256)%256

    ei = chr(((163 * int(ss[i], 2) - key + 256) % 256) ^ int(ys[i], 16))

    #yi = hex(xs[i] ^ ei)

    xs.append(ei)

  return xs



def main():
  
cipher_ctr = ['0X8a', '0X21', '0Xba', '0X24']
  
ps_ctr = ctr_dec(cipher_ctr)
  
print("\nCBC decryption ", ps_ctr)
main()