Transport Layer Security

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Transport Layer Security

• ?????? ????? ???
• ??? ????(????)

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?? ?? TLS Transport Layer Security protocol

• ??? ??? ??????????? ?????? ?????? ??????? ???
  ????????.
• ????????? ????? ?????????? ???/???? ????? ?????
  ?????? ????
• ?????.
• ????? ????.
• ????? ??????.

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????? ???????? TLS ????? ??????
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?????? ?? TLS

• TLS ????? ?????? ??????? ??? ??? ??????.
• TLS ??? ?????? ??? ????? ????? ?? 128 bit RSA
• TLS ???? ?????? "????" ?????? ??????????
  ??????? ???? ?????? ???? ????????? ???? ??????
  ????? ??????.

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?????? ?? TLS

• - Interoperability??????? ????????? ???? ??????
  ???? ????? ??? ??? ?????? ????? ??? ?? ?????? ???
  ????? ?????? ??? ??? ?? ??????.
• TLS ????? ????? ?????? ?? ??? ????????? ?????
  ??????? ????? ?????? ?? ???? ??? ???? ?????
  ????? ??? "?????" .
• ?????? ????? ???????? ???????????? ????? ??????
  ?? ????? (???? ???????) ??? TLS ???? ?????
  ???????? ??? ???? ?????? ?? ??? ?????? ?????.

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????? ?? TLS

• ????? ??????? ?? ???????? TLS ??? ???? ??????
  ?????? ???? ??? ??? ????????? ???????? ?????
  ???? ??????.
• ????????? ????? ???? ?????
• TLS record protocol
• TLS handshake protocol

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TLS record protocol

• TLS record protocol ???? ????? ?????? ?? ????????
  ?????? ???? (?????? TCP) ?????? ?????? ???????
  ???? ??? ????????
• ????? ???? ??????????? ??????? ????? ??????
  ?????? ????? (DES, RC4 ???...) ???? ???? ??????
  ???? ????? ?????? ??? ?????? ??-??? ???????? TLS
  handshake ???? ????? ?????? ?? TLS .

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TLS record protocol-continue

• ????? ???? ????? ?????? ????? ????? ??????
  ??????? ???? MAC. ????? ????? ??????? ????????
  HUSH ???????? ??? SHA , 5MD.
• ????????? ???? ????? ?? ??? MAC ???
  
• ???"? ?? ??????? ?? ?MAC
• ???? ?????? ?? TLS record protocol
• ??? MAC ??? ????? ??????? ??????.

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TLS handshake protocol

• TLS Handshake protocol
• - ????? ????? ????? ???? ????? ????? ????
  ????? ?????? ?????? ?????? ???????????? ??????
  ?????? ???? ??? ???? ?????? ???? ?????? (?????
  ??????).

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TLS handshake protocol-continue

• ????? ?????? ??????? ???? 3 ???????
• 1. ???? ???? ?????? ?? ??? ???? ?-?????? ??
  ?????? (RSA, DSS ???...).
• ????? ????? ?????? ??? ?? ???? ??????? ?? ???
  ??????? ??? ????? ?????? ??? ????? ?????. ?????
  ???? ?????? ??? ??? ?????? ?? ????? ????? ???.
• ????? ???? ????? ?????? ?? ????? ??? ????? ??
  ??? ???? ??????.

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TLS handshake protocol-continue

• ???? ??? ????? ??????? ?????? ???? ????? ??
  ??????? ?? ???? ????????? ???????? ?? ????????
  ??????????.
• ????? ?????? ?????? ???? ?? ??? ?????? ?"? ?????
  ????? ?????? ?????? ???? ??????.

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TLS handshake protocol-continue
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TLS handshake protocol-continue

• ???? ????? ?? ????? ClientHello ???? ???? ????
  ????? ????? ServerHello ???? ???? ????? ?????
  ??????? ?? ?????? ????.
• ?????? ?? ??????? ???????? ?????
• Protocol Version
• Session ID
• CipherSuite
• Compression Method
• random values are generated 2 ?????? ?? ????/????
  ????? ????????.

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TLS handshake protocol-continue

• ??? ??? ??? ???? ????? ?????.
• ?????????? ??? ???? ???? ServerKeyExchange
  ????? ?? ???????? Diffie-Hellman.
• ???? ?? ???????? ??????? ????? ?????? ???? ???
  ??? ?????.

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TLS ??? ??????
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Man in the middle

• Use public private key
• A-gtB hello
• B-gtA Hi, I'm Bob, bobs-public-key
• A-gtB prove it,
• B-gtA Alice, This Is bob
  digestAlice, This Is Bob
• bobs-private-key

This is not secure
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Man in the middle

• Use public private key
• A-gtB hello
• B-gtA Hi, I'm Bob, bobs-certificate
• A-gtB Hi, I'm Bob, bobs-public-key
• B-gtA Alice, This Is bob
  digestAlice, This Is Bob
• bobs-private-key

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Man in the middle

• Alice -gtBob random message
• Bob-gtAlice E(compute digest )
• Alice compute digest to random message, compare
  to Bobs message
• Man in the middle couldnt get the original
  message from the digest.

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Man in the middle

• Also MIM would tackle difficult trying to find a
  different message with the same digest value
  (digital signature)
• While using MAC key as autentification MIM cant
  do damage like in the "???? ????? "

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TLS handshake protocol-continue

• TLS handshake protocol ???? ????? ??-??????????
  ?????? ????? ???? ??????? ???????? ????? ??????
  ????? ???????? ?? ??????, ???? ?? ???? ?????? ??
  ?????? ??? ????.
• ??????????? ?????? ????? ?? "???? ????????" ??
  TLS record protocol ??????? ?? ??????? ?????

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TLS handshake protocol-continue

• - ???? ??? - ???? ???? ??? ????????????
  ??????.
• - ???????? ????? - ???? ?? ???????? ??????
• ?? ???? ??? .
• - ???????? ????? - ???? ?? ????????
• ?????? ?? ???? ???.

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??? ???? ?????????

• ???? ?????
• ??? ?????? ?-TLS ??? ????? ??????? ?? TLS record
  protocol.
• ???? ??????? ?? ???? ????????? ??????? ?? ??
  ??????? ???????? ????? ??????? ?????? ???????
  ????????? ??????, ???????? ??????, ?????????
  ?-MAC .
• ???????? ?? ??????????? ?????? ????
• Bulk encryption key, MAC secret

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??? ???? ?????????-????

• ????? ???? ?????? 4 ???? ?????
• ??? ????? ?????
• ??? ????? ?????
• ??? ??? ????? ?????
• ??? ????? ?????

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??? ???? ?????????-????

• ???????????? ?????? ?? ?????? ???????? ????? ??
  ???TLS handshake protocol ????????? ?? ??
  ???? ????? ??????? ???? ??? ????? ???? ?????.
• ????? ?? "????" ???? ?????? ?? ??? ???? ??????
  ?????? ????? ???? ?????? ?????? ???? ???.

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???? ???? ?????? ?? TLS ????? ????? ??? ?
???? ??? ????
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???? ???? ?????? ?? TLS ????? ????? ??? ?
???????? ???????
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???? ???? ?????? ?? TLS ????? ????? ??? ?
(Advanced????? ??????? ?????(
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???? ???? ?????? ?? TLS ????? ????? ??? ?
TLS" ??? V?? ???? " ?????
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( Thanks )