def decrypt_secret(secret, key):
    """Python implementation of SystemFunction005.

    Decrypts a block of data with DES using given key.
    Note that key can be longer than 7 bytes."""
    decrypted_data = ''
    j = 0   # key index
    for i in range(0,len(secret),8):
        enc_block = secret[i:i+8]
        block_key = key[j:j+7]
        des_key = str_to_key(block_key)

        des = DES.new(des_key, DES.MODE_ECB)
        decrypted_data += des.decrypt(enc_block)
        
        j += 7
        if len(key[j:j+7]) < 7:
            j = len(key[j:j+7])

    (dec_data_len,) = unpack("<L", decrypted_data[:4])
    return decrypted_data[8:8+dec_data_len] 

def get_hbootkey(samaddr, bootkey):
    sam_account_path = ["SAM", "Domains", "Account"]

    root = get_root(samaddr)
    if not root: return None

    sam_account_key = open_key(root, sam_account_path)
    if not sam_account_key: return None

    F = None
    for v in values(sam_account_key):
        if v.Name == 'F':
            F = samaddr.read(v.Data.value, v.DataLength.value)
    if not F: return None

    md5 = MD5.new()
    md5.update(F[0x70:0x80] + aqwerty + bootkey + anum)
    rc4_key = md5.digest()

    rc4 = ARC4.new(rc4_key)
    hbootkey = rc4.encrypt(F[0x80:0xA0])
    
    return hbootkey 

def get_hbootkey(sam_registry, bootkey):
    sam_account_path = ["SAM", "Domains", "Account"]

    sam_account_key = sam_registry.open_key(sam_account_path)

    # Get the F value
    F = sam_account_key.open_value("F").DecodedData
    if not F:
        return F

    md5 = MD5.new()
    md5.update(F[0x70:0x80] + aqwerty + bootkey + anum)
    rc4_key = md5.digest()

    rc4 = ARC4.new(rc4_key)
    hbootkey = rc4.encrypt(F[0x80:0xA0])

    return hbootkey 

def getHBootKey(self):
        LOG.debug('Calculating HashedBootKey from SAM')
        QWERTY = "!@#$%^&*()qwertyUIOPAzxcvbnmQQQQQQQQQQQQ)(*@&%\0"
        DIGITS = "0123456789012345678901234567890123456789\0"

        F = self.getValue(ntpath.join('SAM\Domains\Account','F'))[1]

        domainData = DOMAIN_ACCOUNT_F(F)

        rc4Key = self.MD5(domainData['Key0']['Salt'] + QWERTY + self.__bootKey + DIGITS)

        rc4 = ARC4.new(rc4Key)
        self.__hashedBootKey = rc4.encrypt(domainData['Key0']['Key']+domainData['Key0']['CheckSum'])

        # Verify key with checksum
        checkSum = self.MD5( self.__hashedBootKey[:16] + DIGITS + self.__hashedBootKey[:16] + QWERTY)

        if checkSum != self.__hashedBootKey[16:]:
            raise Exception('hashedBootKey CheckSum failed, Syskey startup password probably in use! :(') 

def __decryptSecret(self, key, value):
        # [MS-LSAD] Section 5.1.2
        plainText = ''

        encryptedSecretSize = unpack('<I', value[:4])[0]
        value = value[len(value)-encryptedSecretSize:]

        key0 = key
        for i in range(0, len(value), 8):
            cipherText = value[:8]
            tmpStrKey = key0[:7]
            tmpKey = self.__cryptoCommon.transformKey(tmpStrKey)
            Crypt1 = DES.new(tmpKey, DES.MODE_ECB)
            plainText += Crypt1.decrypt(cipherText)
            key0 = key0[7:]
            value = value[8:]
            # AdvanceKey
            if len(key0) < 7:
                key0 = key[len(key0):]

        secret = LSA_SECRET_XP(plainText)
        return secret['Secret'] 

def __decryptLSA(self, value):
        if self.__vistaStyle is True:
            # ToDo: There could be more than one LSA Keys
            record = LSA_SECRET(value)
            tmpKey = self.__sha256(self.__bootKey, record['EncryptedData'][:32])
            plainText = self.__cryptoCommon.decryptAES(tmpKey, record['EncryptedData'][32:])
            record = LSA_SECRET_BLOB(plainText)
            self.__LSAKey = record['Secret'][52:][:32]

        else:
            md5 = hashlib.new('md5')
            md5.update(self.__bootKey)
            for i in range(1000):
                md5.update(value[60:76])
            tmpKey = md5.digest()
            rc4 = ARC4.new(tmpKey)
            plainText = rc4.decrypt(value[12:60])
            self.__LSAKey = plainText[0x10:0x20] 

def computeResponseNTLMv1(flags, serverChallenge, clientChallenge, serverName, domain, user, password, lmhash='',
                          nthash='', use_ntlmv2=USE_NTLMv2):
    if user == '' and password == '':
        # Special case for anonymous authentication
        lmResponse = ''
        ntResponse = ''
    else:
        lmhash = LMOWFv1(password, lmhash, nthash)
        nthash = NTOWFv1(password, lmhash, nthash)
        if flags & NTLMSSP_NEGOTIATE_LM_KEY:
           ntResponse = ''
           lmResponse = get_ntlmv1_response(lmhash, serverChallenge)
        elif flags & NTLMSSP_NEGOTIATE_EXTENDED_SESSIONSECURITY:
           md5 = hashlib.new('md5')
           chall = (serverChallenge + clientChallenge)
           md5.update(chall)
           ntResponse = ntlmssp_DES_encrypt(nthash, md5.digest()[:8])
           lmResponse = clientChallenge + '\x00'*16
        else:
           ntResponse = get_ntlmv1_response(nthash,serverChallenge)
           lmResponse = get_ntlmv1_response(lmhash, serverChallenge)
   
    sessionBaseKey = generateSessionKeyV1(password, lmhash, nthash)
    return ntResponse, lmResponse, sessionBaseKey 

def decryptSecret(key, value):
    # [MS-LSAD] Section 5.1.2
    plainText = ''
    key0 = key
    for i in range(0, len(value), 8):
        cipherText = value[:8]
        tmpStrKey = key0[:7]
        tmpKey = transformKey(tmpStrKey)
        Crypt1 = DES.new(tmpKey, DES.MODE_ECB)
        plainText += Crypt1.decrypt(cipherText) 
        cipherText = cipherText[8:]
        key0 = key0[7:]
        value = value[8:]
        # AdvanceKey
        if len(key0) < 7:
            key0 = key[len(key0):]

    secret = LSA_SECRET_XP(plainText)
    return (secret['Secret']) 

def SamDecryptNTLMHash(encryptedHash, key):
    # [MS-SAMR] Section 2.2.11.1.1
    Block1 = encryptedHash[:8]
    Block2 = encryptedHash[8:]

    Key1 = key[:7]
    Key1 = transformKey(Key1)
    Key2 = key[7:14]
    Key2 = transformKey(Key2)

    Crypt1 = DES.new(Key1, DES.MODE_ECB)
    Crypt2 = DES.new(Key2, DES.MODE_ECB)

    plain1 = Crypt1.decrypt(Block1)
    plain2 = Crypt2.decrypt(Block2)

    return plain1 + plain2 

def SamEncryptNTLMHash(encryptedHash, key):
    # [MS-SAMR] Section 2.2.11.1.1
    Block1 = encryptedHash[:8]
    Block2 = encryptedHash[8:]

    Key1 = key[:7]
    Key1 = transformKey(Key1)
    Key2 = key[7:14]
    Key2 = transformKey(Key2)

    Crypt1 = DES.new(Key1, DES.MODE_ECB)
    Crypt2 = DES.new(Key2, DES.MODE_ECB)

    plain1 = Crypt1.encrypt(Block1)
    plain2 = Crypt2.encrypt(Block2)

    return plain1 + plain2 

def decrypt(cls, key, keyusage, ciphertext):
        if len(ciphertext) < 24:
            raise ValueError('ciphertext too short')
        cksum, basic_ctext = ciphertext[:16], ciphertext[16:]
        ki = HMAC.new(key.contents, cls.usage_str(keyusage), MD5).digest()
        ke = HMAC.new(ki, cksum, MD5).digest()
        basic_plaintext = ARC4.new(ke).decrypt(basic_ctext)
        exp_cksum = HMAC.new(ki, basic_plaintext, MD5).digest()
        ok = _mac_equal(cksum, exp_cksum)
        if not ok and keyusage == 9:
            # Try again with usage 8, due to RFC 4757 errata.
            ki = HMAC.new(key.contents, pack('<I', 8), MD5).digest()
            exp_cksum = HMAC.new(ki, basic_plaintext, MD5).digest()
            ok = _mac_equal(cksum, exp_cksum)
        if not ok:
            raise InvalidChecksum('ciphertext integrity failure')
        # Discard the confounder.
        return basic_plaintext[8:] 

def DecryptAttributeValue(dce, attribute):
    sessionKey = dce.get_session_key()
    # Is it a Kerberos Session Key?
    if isinstance(sessionKey, crypto.Key):
        # Extract its contents and move on
        sessionKey = sessionKey.contents

    encryptedPayload = ENCRYPTED_PAYLOAD(attribute)

    md5 = hashlib.new('md5')
    md5.update(sessionKey)
    md5.update(encryptedPayload['Salt'])
    finalMD5 = md5.digest()

    cipher = ARC4.new(finalMD5)
    plainText = cipher.decrypt(attribute[16:])

    #chkSum = (binascii.crc32(plainText[4:])) & 0xffffffff
    #if unpack('<L',plainText[:4])[0] != chkSum:
    #    print "RECEIVED 0x%x" % unpack('<L',plainText[:4])[0]
    #    print "CALCULATED 0x%x" % chkSum

    return plainText[4:]

# 5.16.4 ATTRTYP-to-OID Conversion 

def ComputeSessionKeyStrongKey(sharedSecret, clientChallenge, serverChallenge, sharedSecretHash = None):
    # added the ability to receive hashes already

    if sharedSecretHash is None:
        M4SS = ntlm.NTOWFv1(sharedSecret)
    else:
        M4SS = sharedSecretHash

    md5 = hashlib.new('md5')
    md5.update('\x00'*4)
    md5.update(clientChallenge)
    md5.update(serverChallenge)
    finalMD5 = md5.digest()
    hm = hmac.new(M4SS) 
    hm.update(finalMD5)
    return hm.digest() 

def aes_encrypt(key, iv, content):
    """
    AES加密
    key,iv使用同一个
    模式cbc
    填充pkcs7
    :param key: 密钥
    :param content: 加密内容
    :return:
    """
    cipher = AES.new(key, AES.MODE_CBC, iv)
    # 处理明文
    content_padding = pkcs7padding(content)
    # 加密
    encrypt_bytes = cipher.encrypt(bytes(content_padding, encoding='utf-8'))
    # 重新编码
    result = str(base64.b64encode(encrypt_bytes), encoding='utf-8')
    return result 

def aes_decrypt(key, iv, content):
    """
    AES解密
     key,iv使用同一个
    模式cbc
    去填充pkcs7
    :param key:
    :param content:
    :return:
    """
    cipher = AES.new(key, AES.MODE_CBC, iv)
    # base64解码
    encrypt_bytes = base64.b64decode(content)
    # 解密
    decrypt_bytes = cipher.decrypt(encrypt_bytes)
    # 重新编码
    result = str(decrypt_bytes, encoding='utf8')
    # 去除填充内容
    result = pkcs7unpadding(result)
    return result 

def decrypt_aes(secret, key):
    """
    Based on code from http://lab.mediaservice.net/code/cachedump.rb
    """
    sha = SHA256.new()
    sha.update(key)
    for _i in range(1, 1000 + 1):
        sha.update(secret[28:60])
    aeskey = sha.digest()

    data = ""
    for i in range(60, len(secret), 16):
        aes = AES.new(aeskey, AES.MODE_CBC, '\x00' * 16)
        buf = secret[i : i + 16]
        if len(buf) < 16:
            buf += (16 - len(buf)) * "\00"
        data += aes.decrypt(buf)

    return data 

def get_lsa_key(secaddr, bootkey):
    root = get_root(secaddr)
    if not root:
        return None

    enc_reg_key = open_key(root, ["Policy", "PolSecretEncryptionKey"])
    if not enc_reg_key:
        return None

    enc_reg_value = enc_reg_key.ValueList.List[0]
    if not enc_reg_value:
        return None

    obf_lsa_key = secaddr.read(enc_reg_value.Data.value,
            enc_reg_value.DataLength.value)
    if not obf_lsa_key:
        return None

    md5 = MD5.new()
    md5.update(bootkey)
    for i in range(1000):
        md5.update(obf_lsa_key[60:76])
    rc4key = md5.digest()

    rc4 = ARC4.new(rc4key)
    lsa_key = rc4.decrypt(obf_lsa_key[12:60])

    return lsa_key[0x10:0x20] 

def decrypt_single_hash(rid, hbootkey, enc_hash, lmntstr):
    (des_k1,des_k2) = sid_to_key(rid)
    d1 = DES.new(des_k1, DES.MODE_ECB)
    d2 = DES.new(des_k2, DES.MODE_ECB)

    md5 = MD5.new()
    md5.update(hbootkey[:0x10] + pack("<L",rid) + lmntstr)
    rc4_key = md5.digest()
    rc4 = ARC4.new(rc4_key)
    obfkey = rc4.encrypt(enc_hash)
    hash = d1.decrypt(obfkey[:8]) + d2.decrypt(obfkey[8:])

    return hash 

def ds_decrypt_pek(bootkey, enc_pek):
    md5=MD5.new()
    md5.update(bootkey)
    for i in range(1000):
        md5.update(enc_pek[0:16])
    rc4_key=md5.digest();
    rc4 = ARC4.new(rc4_key)
    pek=rc4.encrypt(enc_pek[16:])
    return pek[36:] 

def ds_decrypt_single_hash(rid, enc_hash):
    (des_k1,des_k2) = sid_to_key(rid)
    d1 = DES.new(des_k1, DES.MODE_ECB)
    d2 = DES.new(des_k2, DES.MODE_ECB)
    hash = d1.decrypt(enc_hash[:8]) + d2.decrypt(enc_hash[8:])
    return hash 

def handshake(key, chall):
    #https://tools.ietf.org/html/rfc6143#section-7.2.2
    #http://www.vidarholen.net/contents/junk/vnc.html
    #Truncate to 8 chars
    key = key[:8]
    # Convert to binary
    binary = (' '.join(format(ord(x), 'b') for x in key))
    binaryList = binary.split()
    count = 0
    #Add leading zeros
    for x in binaryList:
        binaryList[count] = ("0" * (8 - len(binaryList[count]))) + binaryList[count]
        count += 1

    # Function to mirror the byte
    def bitMirror(byte):
        return byte[::-1]
    flipkey = ""
    # turn back into binary
    for x in binaryList:
        flipkey += struct.pack('B', int(bitMirror(x), 2))
    #Pad with NULL bytes
    flipkey += "\x00" * (8 - len(flipkey))
    #Encryptwith DES
    des = DES.new(flipkey, DES.MODE_ECB)

    #challenge from server
    challenge = chall
#    challenge= chall.decode("hex")
    response = des.encrypt(challenge)
#    return ''.join(x.encode('hex') for x in response)
    return response 

def decrypt_xor(key, data):
    cipher = XOR.new(key)
    return cipher.decrypt(data)


# RC4 

def decrypt_arc4(key, data):
    cipher = ARC4.new(key)
    return cipher.decrypt(data)


# DES 

def decrypt_des_ecb(key, data, iv=None):
    mode = DES.MODE_ECB
    if iv:
        cipher = DES.new(key, mode, iv)
    else:
        cipher = DES.new(key, mode)
    return cipher.decrypt(data) 

def decrypt_des_cbc(key, data, iv=None):
    mode = DES.MODE_CBC
    if iv:
        cipher = DES.new(key, mode, iv)
    else:
        cipher = DES.new(key, mode)
    return cipher.decrypt(data)


# DES3 

def decrypt_des3(key, data):
    cipher = DES3.new(key)
    return cipher.decrypt(data)


# AES 

def decrypt_aes_cbc_iv(key, iv, data):
    mode = AES.MODE_CBC
    cipher = AES.new(key, mode, IV=iv)
    return cipher.decrypt(data)


# Blowfish 

def decrypt_blowfish(key, data):
    cipher = Blowfish.new(key)
    return cipher.decrypt(data)


# RC6 - Custom 

def hash_lm(pw):
    pw = pw[:14].upper()
    pw = pw + ('\0' * (14 - len(pw)))
    d1 = DES.new(str_to_key(pw[:7]), DES.MODE_ECB)
    d2 = DES.new(str_to_key(pw[7:]), DES.MODE_ECB)
    return d1.encrypt(lmkey) + d2.encrypt(lmkey) 

def hash_nt(pw):
    return MD4.new(pw.encode('utf-16-le')).digest()