1 00:00:00,660 --> 00:00:06,120 The first encryptions they are going to talk about breaking it is going to be WEP encryption because 2 00:00:06,150 --> 00:00:07,280 it's the oldest one. 3 00:00:07,320 --> 00:00:09,090 It's the easiest one to break. 4 00:00:09,270 --> 00:00:14,340 But we still need to learn how to break it because you will see networks that still use with encryption 5 00:00:15,480 --> 00:00:23,550 encryption uses an algorithm called R-S.C. for each packet is encrypted at the access point and then 6 00:00:23,550 --> 00:00:25,020 it's sent to the air. 7 00:00:25,020 --> 00:00:30,750 Once the client receives it since the client has the key it will be able to decrypt the packet and read 8 00:00:30,750 --> 00:00:32,280 the information inside it. 9 00:00:32,280 --> 00:00:37,890 So very simple Acholi the IP encrypted packet sent that client to receive it. 10 00:00:37,890 --> 00:00:40,680 The client has the key so the client decrypt it. 11 00:00:40,680 --> 00:00:47,100 Same way when the client says the packet it's encrypted encrypted and then send it in the air the access 12 00:00:47,100 --> 00:00:48,310 point to receive it. 13 00:00:48,420 --> 00:00:52,030 The access point has the key so it'll decrypt the packets. 14 00:00:52,200 --> 00:01:00,060 So each packet sent into the air has a unique keystream which ensures that the keystream is unique by 15 00:01:00,130 --> 00:01:03,980 using 24 bit initialization vector. 16 00:01:04,050 --> 00:01:11,310 So the initialization vector is a random number it's sent into each packet and it's sent into plaintext. 17 00:01:11,310 --> 00:01:13,890 So this part is not encrypted. 18 00:01:13,890 --> 00:01:17,600 If you read the packet you'll be able to read it in plain text. 19 00:01:17,810 --> 00:01:24,110 The problem with the IP or the initialization vector it's very short the 24 bits is not that long. 20 00:01:24,120 --> 00:01:30,180 So in a busy network there would be a very large number of packets sent into the air. 21 00:01:30,180 --> 00:01:38,040 This means the number of possibilities of random IPs will be exhausted and we will have to Pakistan 22 00:01:38,040 --> 00:01:41,460 have the same initialization vector. 23 00:01:41,530 --> 00:01:49,030 So the initialization vector is a 24 bit random keep it sent into the air in each packet and it's sent 24 00:01:49,120 --> 00:01:53,500 into plaintext as the plaintext in a busy network. 25 00:01:53,500 --> 00:01:56,150 We're going to have a very large number of packets. 26 00:01:56,170 --> 00:02:03,580 This means that the possibilities of unique IPs will be exhausted and that we will who are sniffing 27 00:02:03,580 --> 00:02:10,360 these all these packets who will be able to collect two packets that have the same initialization vector. 28 00:02:10,360 --> 00:02:17,720 Once we have two packets they have the same initialization vector aircraft energy can be used to use 29 00:02:17,740 --> 00:02:21,130 statistical attacks to determine the keystream. 30 00:02:21,130 --> 00:02:24,480 And after that it will be able to determine the work. 31 00:02:25,010 --> 00:02:25,360 OK. 32 00:02:25,360 --> 00:02:32,350 So from the above we know the more Ivey's or initialization vectors that we collect the more likely 33 00:02:32,350 --> 00:02:35,390 that will successfully crack the whip. 34 00:02:35,680 --> 00:02:43,670 So our main goal now when we try to crack WEP is to collect as much as we can because once we have a 35 00:02:43,680 --> 00:02:49,560 lot a large number of IPs and we're going to have two packets they use the same IP then aircraft ngi 36 00:02:49,570 --> 00:02:53,940 is more likely to be able to determine the keystream. 37 00:02:53,980 --> 00:02:59,010 And they were key for the target network and the next video will do that. 38 00:02:59,020 --> 00:03:00,970 We'll see how that actually works. 39 00:03:01,180 --> 00:03:03,120 And it should be easier to understand.