drsuapi.py 文件源码

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