21 VoIP An encrypted VoIP communication system for mobile telephones 1095702 2010 3 4
VoIP, IP., IP, VoIP(Voice over Internet Protocol)., VoIP,., VoIP over SSL(VoIPs), VoIPs.,,.,, VoIP., LAN VoIP. LAN VoIP, VoIP,. VoIP,,, SAS-2,, IP, i
Abstract An encrypted VoIP communication system for mobile telephones Yuta, Ishii In recent years, movement to integrate the public telephone net and the IP network is advanced. In the movement, VoIP(Voice over Internet Protocol) to communicate the voice-data by the IP network is used. However, VoIP using the public network has danger. In order to solve this problem, there is a method of using VoIPs(VoIP over SSL). However, VoIPs keeps using the same encryption key while talking over the mobile phone. Therefore, when he/she had the encryption key stolen, hiding the content of the telephone call secretly can not be kept. As the earlier study, the VoIP communication that improve degree of hiding the content of the telephone call have been As the earlier study, the VoIP communication in same LAN with a portable terminal has been achieved. In this study, we have achieved the VoIP communication with different LAN, and exchanged address information of the lobby server with other party beforehand. key words VoIP, Encryption, One-time password, SAS-2, lobby server, IP network, mobile phone ii
1 1 1.1................................... 1 1.2................................. 2 2 VoIP 3 2.1 VoIP..................................... 3 2.1.1 VoIP/H.323.............................. 3 2.1.2 VoIP/SIP............................... 5 2.2 VoIP over SSL................................ 8 3 9 3.1 SAS-2.............................. 9 3.1.1............................... 9 3.1.2 SAS-2........................... 10 3.1.3 /.............................. 13 4 SAS-Phone 14 4.1................................. 15 4.2.................................. 16 4.2.1 SET UP PHASE........................... 16 4.2.2 AUDIO TRANSEFER PHASE................... 17 5 VoIP 19 5.1................................... 20 5.2................................. 20 iii
5.2.1............................. 21 5.2.2............................. 22 5.2.3............................. 23 5.2.4............................. 23 6 26 6.1................................... 26 6.2................................... 26 6.3...................................... 27 7 28 29 30 iv
2.1 H.323................................ 4 2.2 H.323............................. 6 2.3 VoIP/SIP.......................... 7 3.1 H.323................................ 11 3.2 H.323................................ 12 4.1 SAS-Phone............................. 15 4.2 SAS-Phone.......................... 16 4.3 SET UP PHASE............................... 17 4.4 AUDIO TRANSEFER PHASE....................... 18 5.1.............................. 21 5.2......................... 21 5.3 VoIP....................... 22 5.4 VoIP............................. 23 5.5......................... 24 5.6......................... 25 v
2.1 H.323.......................... 5 2.2 VoIP/SIP........................ 7 6.1.................................... 27 6.2................................ 27 vi
1,,.,. 1.1, LAN, IP [1].,, PBX Private Branch exchange,,.,, 2., PBX IP-PBX,,.[2].,. IP, VoIP Voice over Internet Protocol [3]. VoIP, LAN VoWLAN Voice over Wireless LAN., VoWLAN,, VoWLAN [4]. VoWLAN,,.,,, [5].,, VoIPs 1
1.2 VoIP over SSL. VoIPs, VoIP SSL,. VoIPs,,,.,, VoIP., LAN VoIP., VoIP, VoIP, LAN VoIP. 1.2, LAN, VoIP., VoIP,.,, SAS-2., SAS-Phone,.,.,,.,,.,,. 2
2 VoIP VoIP, VoIP., VoIP. 2.1 VoIP, IP.,, IP.,, LAN WAN IP, VoIP. VoIP, (ITU-T) VoIP/H.323, VoIP/SIP(Voice over Internet Protocol / Session Initiation Protocol)., VoIP/H.323 VoIP/SIP. 2.1.1 VoIP/H.323 H.323,, [6]. VoIP/H.323, 2.1,,,, MCU(Multipoint Control Unit).,,,., ISDN H.323 3
2.1 VoIP 2.1 H.323 H.323, IP., IP,. MCU,.,,. 2.1. H.323 4,., H.225.0 RAS Q.931. H.225.0 RAS, VoIP, Q.931 VoIP., H.245 RTP(Real - time Transport Protocol), RTCP(Real - time Transport Control Protocol) H.245, VoIP, RTP, RTCP VoIP. H.323, 4. 2.2, H.323., SET UP, H.225.0 RAS Q931. 4
2.1 VoIP 2.1 H.323 RTP RTCP RAS Q.931 H.245 ( ) (H.225.0) (H.225.0) (H.225.0) UDP TCP IP CONTROL SIGNALLING, H.245. AUDIO,. RELEASE, H.245 VoIP. VoIP/H.323, IP., VoIP/H.323 DoS,, VoIP/SIP., VoIP/SIP, VoIP/H.323, ASN.1(Abstract Syntax Notation One),. 2.1.2 VoIP/SIP SIP,,,, [7][8]. SIP,, H.323,. 2.2. VoIP/SIP,,, /. VoIP/SIP, VoIP/SIP, SIP. SIP,, 2 5
2.1 VoIP 2.2 H.323.,,.,,., VoIP/SIP, 2.3., A SIP A INVITE. INVITE 6
2.1 VoIP 2.2 VoIP/SIP SIP RTP SDP SIP RTPRTCP/ DNS TCP UDP 2.3 VoIP/SIP SIP, SIP INVITE, 100 Trying., INVITE, 100 Trying, INVITE. B INVITE, SIP A 180 Ringing, 200 OK. A 7
2.2 VoIP over SSL 200 OK, A B., A SIP, B ACK.,,,., BYE, BYE 200 OK.,,,. 2.2 VoIP over SSL VoIP over SSL, VoIP. H.323 VoIP/SIP,,., VoIP SSL, VoIP,., VoIP.,,.,,,., VoIP over SSL,,,,.,,. 8
3,, SAS-2., SAS-2,,. 3.1 SAS-2 SAS-2, [9].,, Replay Attack Man-in-the-middle Attack.,,,.,., SAS-2,. 3.1.1 SAS-2. User,. Server, User. ID,. S,. 9
3.1 SAS-2 X, F, H,., H(x) x.,. i,. N i, i. +,.,. 3.1.2 SAS-2 SAS-2,.,,.,,,., 3.1,. 1., ID, S., N 1,. ID, S, N 1, A + X(ID, S N 1 ). 2., ID, A. 3., ID, A.,. 3.2,,. 1., ID, S., N i, A = X(ID, S bigoplus N i )., N i +1,., C = X(ID, S N i +1), F(C) = F(ID, C), C, F(C), N i +1 α = C (F(C) + A), β = F(C) A. 10
3.1 SAS-2 3.1 H.323 2., ID, α, β.,. 3., β A, F(C) + β A., C = α (F(C) + A). F(C), F(ID, C),.,. 4., A C,., γ = H(ID, F(C)). 5., γ. 6., H(ID, F(C)), γ.,.,. 11
3.1 SAS-2 3.2 H.323,.,.,,. SAS-2 (i+1),. α E (F (E) + C) β F (E) C ID,,. 12
3.1 SAS-2 α x (F (E) + C) β F (x) C ID, i,., SAS-2. 3.1.3 / SAS-2, SAS-2,..,,.,. 13
4 SAS-Phone, SAS-Phone, [10].,,. X,. Y,. ID, S,. D, X, F, H,., H(x) x.,. i,. N i, i. X a, X. Y a, Y. T,. M,. M k,. M e, M M k. +,.,. 14
4.1 4.1 ipod touch 2G.,, API. SAS-Phone VoIP, 4.1.,, [10].,., 200ms,,., AES. WirelessLAN.,..,.,..,, SAS-2. 4.1 SAS-Phone 15
4.2 4.2, 4.2., SET UP PHASE.,, FIRST KEY EXCHANGE.,, AUDIO TRANSEFFR PHASE.,,. 4.2 SAS-Phone 4.2.1 SET UP PHASE SET UP PHASE 4.3, SET UP PHASE. SET UP PHASE,, X Y., X X a., X Y., Y, Y a., Y. Y, X. X, X a Y. X a Y,, 16
4.2., Y, X a, Y a, T., Y X, X T., SET UP PHASE. 4.3 SET UP PHASE 4.2.2 AUDIO TRANSEFER PHASE AUDIO TRANSEFER PHASE,., SAS-2., 4.4., X F(C) M k., M M k. M e, LAN X Y., Y F(C) M k., Y M k, M k M., Y M., AUDIO TRANSEFER PHASE. 17
4.2 4.4 AUDIO TRANSEFER PHASE 18
5 VoIP, VoIP,.,,, VoIP.,,.,. X,. Y,. Z,,. ID, S,. D, X, F, H,. F(x) x.,. i,. N i, i. M,. M k,. M e, M M k,. 19
5.1 +,.,. 5.1, VoIP, VoIP IP. VoIP 5.1, IP VoIP. 1. A, 2. VoIP B 3. VoIP 4. URL, B 5. B URL, 6. B, A 7. A, VoIP 5.2, SAS-2 VoIP.,,,,., 5.2., VoIP. VoIP 3,,,.,. 20
5.2 5.1 5.2 5.2.1, VoIP, SAS-2. 5.3, VoIP., X, LAN SSL., X, SAS-2. 21
5.2 5.3 VoIP 5.2.2, VoIP. VoIP, 5.4., X SSL,. X, VoIP Y,., VoIP, Y URL. Y, URL. 22
5.2 5.4 VoIP 5.2.3, VoIP VoIP Socket. 5.5, VoIP Socket., Y,. Y, X., X, Y OK, X Y VoIP. 5.2.4, VoIP VoIP. 5.6,., X F(x) M k., M M k. M e, LAN, X Z. Z, F(C), M k. Z, M k M k M., Z Y. Y, M. 23
5.2 5.5 24
5.2 5.6 25
6,.,,.,,,. 6.1,,., 1MB(1,085,597byte)., 6.1., iphone, MacBookAir MacPro. 6.2,, TCP., TCP.,,., 6.2. 26
6.3 LAN 6.1 MacBookAir 1.6GHz Intel Core 2 Duo 2GB 1067MHz DDR3 CentOS Intel(R) Pentium(R) 4 CPU 3.00GHz 1GB MacPro 2 x 2 GHz Dual-Intel Xeon 4GB IPN-W500AP 54Mbps 6.2 5.270000ms 0.050000ms 1.670000ms 6.3 0.05,.,, SAS-2. 27
7,, SAS-2.,,,., LAN,., SAS-2,.,,, SAS-2 VoIP. 28
,,,,,,,., 29
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