my.py

# Mifare classic access bits
# Example: accessbits([0,0,0,1])
def accessbits(acbits):
  bm=[[0,0,0],[0,0,1],[0,1,0],[0,1,1],[1,0,0],[1,0,1],[1,1,0],[1,1,1]]
  invert = lambda arr: [[1,0][x] for x in arr]
  def convert(arr):
    s=0
    for n in range(len(arr)):
      s=s+arr[-1-n]*2**n
    return s
  ac=[bm[x] for x in acbits]
  arrn=[[],[],[],[]]
  for i in [2,1,0]:
    for j in [3,2,1,0]:
      arrn[i].append(ac[j][i])
  b6=convert(invert(arrn[1]) + invert(arrn[0]))
  b7=convert(arrn[0] + invert(arrn[2]))
  b8=convert(arrn[2] + arrn[1])
  return [hex(b6), hex(b7), hex(b8)]