Hi I am trying to implement D Function in python. import hashlib from Crypto.Cipher import AES from Crypto.Hash import SHA from Crypto.Util.Padding import pad as padding from Crypto.PublicKey import RSA PRIME = 813416437 NB_RD = 16 def dfunction(R2, ASk): tmp = bytearray(20) pad = bytearray(64) MBlock = [0] * 14 P = PRIME if len(R2) >= 56: return -1 # kDRMSKDServerParamErr # Padding until a multiple of 56B pad[:len(R2)] = R2 pad[len(R2)] = 0x80 pad[len(R2) + 1:56] = [0] * (56 - len(R2) - 1) # Create 14 32b values for i in range(14): MBlock[i] = (pad[4 * i] << 24) ^ (pad[4 * i + 1] << 16) ^ (pad[4 * i + 2] << 8) ^ pad[4 * i + 3] # Reunify into 2 32 bits values #MBlock[0] += sum(MBlock[1:7]) #MBlock[1] = 0 #MBlock[1] += sum(MBlock[7:]) # Reunify into 2 32 bits values for i in range(1, 7): MBlock[0] += MBlock[i] MBlock[1] = 0 for i in range(7): MBlock[1] += MBlock[i + 7] # Apply the function (C_r) for i in range(2): for r in range(NB_RD): if MBlock[i] & 1: MBlock[i] >>= 1 else: MBlock[i] = (3 * MBlock[i] + 1) % P # Append to M for i in range(4): pad[56 + i] = (MBlock[0] >> (8 * i)) & 0xFF pad[60 + i] = (MBlock[1] >> (8 * i)) & 0xFF h = hashlib.sha1() h.update(pad) hh = h.digest()[:16] cipher = AES.new(ASk, AES.MODE_ECB) DASk = cipher.encrypt(padding(hh, AES.block_size)) return DASk Then, i am trying to match integrities and they does not match. I think there is an mistake in D Function implementation. Any clue whats wrong? Thank you

Hi I was wondering if there any D Function implementations on Python to derive dASK? Thank you