Internet Protocol - Research by Kirils Solovjovs

Recommendations

Info

Skype protocol 78 password is used as a shared secret with the login server. The plain session key is hashed into a 256-bit AES key that is used to encrypt the session's public RSA key and the shared secret. The encrypted session key and the AES encrypted value are sent to the login server. On the login server side, the plain session key is obtained by decrypting the encrypted session key using the login server's private RSA key. The plain session key is then used to decrypt the session's public RSA key and the shared secret. If the shared secret match, the login server will sign the user's public RSA key with its private key. The signed data is dispatched to the super nodes. Upon searching for a buddy, a super node will return the buddy's public key signed by Skype. The SC will authenticate the buddy and agree on a session key by using the mentioned RSA key. UDP UDP packets: IP UDP Skype SoF Skype Crypted Data01 The Start of Frame (SoF) consists of: 1. frame ID number (2 bytes) 2. payload type (1 byte) • obfuscated payload • Ack/NAck packet • payload forwarding packet • payload resending packet • other Obfuscation Layer The RC4 encryption algorithm is used to obfuscate the payload of datagrams. 1. The CRC32 of public source and destination IP, Skype's packet ID are taken 2. Skype obfuscation layer's initialization vector (IV). The XOR of these two 32-bit values is transformed to an 80-byte RC4 key using an unknown key engine. A notable misuse of RC4 in Skype can be found on TCP streams (UDP is unaffected). The first 14 bytes (10 of which are known) are XOR-ed with the RC4 stream. Then, the cipher is reinitialized to encrypt the rest of the TCP stream. [8]
Skype protocol 79 TCP TCP packets: TCP Skype Init TCP packet The Skype Init TCP packet contains • the seed (4 bytes) • init_str string 00 01 00 00 01 00 00 00 01/03 Low-level datagrams Almost all traffic is ciphered. Each command has its parameters appended in an object list. The object list can be compressed. Enc -> Cmd -> Encod / Object List ... -| ^ \ Compressed List ... -| Frag | | Ack NAck Object Lists |------------------ Forwarded..Message An object can be a number, string, an IP:port, or even another object list. Each object has an ID. This ID identifies which command parameter the object is. Object: Object List Number IP:Port List of numbers String RSA key List Size (n) Object 1 . . Object n
Page 1 and 2:
An Introduction to Computer Network
Page 3 and 4:
--WEEK ONE-- 1
Page 5 and 6:
Internet 3 Internet portal World Wi
Page 7 and 8:
Internet 5 in the late 1980s and ea
Page 9 and 10:
Internet 7 Internet, though they ma
Page 11 and 12:
Internet 9 Services World Wide Web
Page 13 and 14:
Internet 11 Digital media streaming
Page 15 and 16:
Internet 13 In an American study in
Page 17 and 18:
Internet 15 Internet, Berdal also n
Page 19 and 20:
Internet 17 [32] Walter Willinger,
Page 21 and 22:
Internet 19 • "The Internet sprea
Page 23 and 24:
Internet protocol suite 21 The netw
Page 25 and 26:
Internet protocol suite 23 Layers i
Page 27 and 28:
Internet protocol suite 25 3. The S
Page 29 and 30: Internet protocol suite 27 Applicat
Page 31 and 32: Internet protocol suite 29 implemen
Page 33 and 34: OSI model 31 OSI model The Open Sys
Page 35 and 36: OSI model 33 Parallel SCSI buses op
Page 37 and 38: OSI model 35 While Generic Routing
Page 39 and 40: OSI model 37 5 Session ISO/IEC 8327
Page 41 and 42: OSI model 39 citeseerx. ist. psu. e
Page 43 and 44: Internet Protocol 41 The Internet P
Page 45 and 46: Transmission Control Protocol 43 re
Page 47 and 48: Transmission Control Protocol 45 tw
Page 49 and 50: Transmission Control Protocol 47 Co
Page 51 and 52: Transmission Control Protocol 49 Er
Page 53 and 54: Transmission Control Protocol 51 se
Page 55 and 56: Transmission Control Protocol 53 Co
Page 57 and 58: Transmission Control Protocol 55 Al
Page 59 and 60: Transmission Control Protocol 57
Page 61 and 62: Transmission Control Protocol 59
Page 63 and 64: User Datagram Protocol 61 Checksum
Page 65 and 66: User Datagram Protocol 63 Applicati
Page 67 and 68: Internet Control Message Protocol 6
Page 69 and 70: Internet Control Message Protocol 6
Page 71 and 72: Hypertext Transfer Protocol 69 HTTP
Page 73 and 74: Hypertext Transfer Protocol 71 Is u
Page 75 and 76: Hypertext Transfer Protocol 73 Secu
Page 77 and 78: Hypertext Transfer Protocol 75 [17]
Page 79: Skype protocol 77 Login A Skype cli
Page 83 and 84: Skype protocol 81 • L. De Cicco,
Page 85 and 86: BitTorrent 83 Operation A BitTorren
Page 87 and 88: BitTorrent 85 order to complete the
Page 89 and 90: BitTorrent 87 table capacities. Bit
Page 91 and 92: BitTorrent 89 torrent for each encl
Page 93 and 94: BitTorrent 91 Legal issues There ha
Page 95 and 96: BitTorrent 93 [50] http:/ / bittorr
Page 97 and 98: Architectural Principles Encapsulat
Page 99 and 100: Packet switching 97 Baran's study m
Page 101 and 102: Packet switching 99 References [1]
Page 103 and 104: Hostname 101 rr.pmtpa.wikimedia.org
Page 105 and 106: End-to-end principle 103 History Th
Page 107 and 108: End-to-end principle 105 [5] Saltze
Page 109 and 110: Finite-state machine 107 Finite-sta
Page 111 and 112: Finite-state machine 109 Fig. 2 SDL
Page 113 and 114: Finite-state machine 111 Classifica
Page 115 and 116: Finite-state machine 113 orthogonal
Page 117 and 118: Finite-state machine 115 [8] Alur,
Page 119 and 120: Finite-state machine 117 Finite Mar
Page 121 and 122: Article Sources and Contributors 11
Page 127: License 125 License Creative Common
show all

Internet Protocol - Research by Kirils Solovjovs

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?