Fourth Edition by William Stallings

1
???????????5?????????AES

• Fourth Edition by William Stallings
• Slides by ???
• syang_at_ustc.edu.cn
• http//staff.ustc.edu.cn/syang
• 2012?9?

2
??????AES??

• AES???????,????DES????????????128?,?????128??192??
  256??
• AES????Feistel??,?????????????????????????????,??
  ?????????

3
AES?????

• AES???
• ??DES????,???3DES,??168?,???????????3DES?????????,
  ???,?64??
• ??????????NIST?1997??????,????128?,??128?192?256??
  
• 15??????1998?6?????????,??5??????1999?8??????????
  
• 2000?10?,NIST??Rijndael??AES??,
  Rijndael????????????Joan Daemen???Vincent
  Rijmen???
• 2001?11?,NIST???????????? FIPS PUB 197?

4
AES???

• AES?????????
• ?????????????????????
• ????AES?????????????,??????
• ????????????????????????????????,???????

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(No Transcript)
6
(No Transcript)
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AES????

• ?????
• ??????????????
• ????
• ??????,???????????????????
• ??????
• ??????????
• ????
• ?????????????????
• ??????
• ????????
• ?????
• ?????
• ???????????
• ???????????
• ??????????

8
(No Transcript)
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(No Transcript)
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NIST?AES???

• ????????
• 128???,?????????128/192/256?
• ???Triple-DES??????
• ????????20-30?
• ??????????????
• ???C?Java??
• NIST???????????????????,??????,???Rijndael

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AES??

• AES??????128?,??????? 128/192/256?????
• ???Feistel???????????
• ????4?,??4??
• ????????????
• Rijndael??????
• ?????????????
• ???CPU??????????????
• ????

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AES???
13
AES??????
14
AES?????
15
AES???

• ?Feistel??
• ???????44?32???????wi
• ?????????
• ???????S????????????
• ??????????
• ???????GF(28)?????????
• ???????????????????????XOR
• ????????
• ??????????????
• ???????????????????????
• ???????
• ?????????????,?????????
• ?????????,??????????????
• ????????????????????

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Rijndael??

• 128?????4?,??4??(state)
• ??state??9/11/13???
• ????(????????S?)
• ?????(????????)
• ?????(???????)
• ????(?????state)
• ????????????????,???????????

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AES???????
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??????

• ????????????
• ????16x16????,???????256?8?????
• ??????4????,?4?????????
• ????95??9??5???????
• ?????2A
• S???GF(28)????????????
• ??????????

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AES???????????????????
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(No Transcript)
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(No Transcript)
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?????

• ???????
• State??1?????
• State??2?????1???
• State??3?????2???
• State??4?????3???
• ???????????????????
• ??State??????,??????????????????

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(No Transcript)
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?????

• ????????????????
• ????????????????,?????4???????????
• ?????????State???????,??????m(x) x8x4x3x1,
  GF(28)
• ???????????????

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??????

• ?????????128??State???128???????(XOR)
• ????State????,??State?????4????????1??????
• ???????????????????,????????????
• ??????????,????State?????

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AES?????

• AES??????????4?(16??),???44?(??52?, ?60?),??32?
• ??????????????????4??
• ?????4???????????????
• ?????????????

27
??????

• AES????????????,??????????????????????
• ????????????????,????????????
• ??????????
• ??????????

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AES???

• ???8????????????
• ????????????????,?????256????
• ????????????
• ???????????
• ?????????GF(28)????,????????????,?????????
• ???32????????????
• ??????32????
• ?????4?256???
• ????????????4????????????
• ??16Kb??????4??

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Summary

• We have considered
• the AES selection process
• the details of Rijndael the AES cipher
• looked at the steps in each round
• the key expansion
• implementation aspects