? ? ? Cryptography

1
?????????

• ???

2
1.????

• ???????
• ???
• ??
• ??
• ????????

3
1.1???????
??????
?????
1.??????????????
3.????
2.????
4.???? ??
5.??
????
???
??
??
????
4
1.2???

• ????????????????,??????????(?????????????),???????
  ??(???????)?
• ???????????????????????????

??????????????
????
?????
??????
????
5
1.3??

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

????? ????
??
??????
????
6
1.4??

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

???? ??
?????
????
7
1.5????????

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

8
2.???

• ??
• ???????
• ???????
• ?????
• ??????
• ???????

9
2.1??

• ?? ?????????????
• ??????????????????????????
• ??????????????????????

10
2.2???????
?? Encryption
?? Ciphertext
?? Plaintext
?/???? Key
?? Decryption
11
2.3???????
??
digital signature, Authentication, SSL,SET
?????
DES,RAS
???/???
Symmetric / Asymmetric Cryptography
12
2.4?????

• ???Symmetric Cryptography???????????
• ??,??
• DES (Data Encryption Standard)
• ????Asymmetric Cryptography???????????,??????(Pub
  lic Key)???
• RSA (Rivest, Shamir, and Adleman)

13
2.5?????????
?? ??
???????????
14
????????-DES

• DES(Data Encryption Standard)?????????1976????????
  ,????????,DES?????????????????(unclassified)???DES
  ????64??,???????????1??????(parity)??,?????56??,DE
  S?????????16???????????Key????

15
2.6???????

• ???? ????????(Public Key)???, ?1976?? Whitfield
  Diffie ? Martin Hellman ??????????????,???????????
  ???????????
• ????????????????,?????????,?????,??????(Private
  Key)????????,??????(Public Key)?

16
??????????
??
?? ??
?????????
17
?????????-RSA

• MIT??????1978????RSA???, ?????????,RSA????????????
  Rivest, Shamir and Adleman,??????????RSA?????????

18
3.?????????

• ????
• ????
• ???????
• ??????
• ????

19
3.1????

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

20
??????
?? ???
21
????????????
??? ????
??? ????
?? ???
?? ??
?? ??
??

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

??? ????
??? ????
22
3.2????

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

23
??????
??? ????
???/?? ??
???? ??
??
??
?? ??
??
??
??? ????
???? ??
???/?? ??
??
??
?? ??
??
24
3.3???????

• ?????????????,?????????,???????????????,??????????
  ???
• ????(message digest)??????????????,???????????????
  ?????

25
?????????-Hash

• ??(Hash)??????????????,????????????????????
• ?????????(???)??,??????????????????,???????,??????
  ??????????
• ????????????,???????????

26
Hash??
???????????????????????????,???????????????,??????
,?????????????????
27
3.4??????-???

2.??
3.??

5.??

1.????
4.??
28
3.4??????-???
6.????? ????
7.?????
4.????? ????
3.??
5.??
1.??

2.??
9.?? ????
8.????
29
4.????

• ??????
• ????
• ????
• ????
• ????
• ????

30
4.1??????

• ?????
• ?????????????,???????????
• ??????
• ????????
• ????????(??????E-Mail)
• ???(??)????
• ?????????

31
4.2??????

• ????
• ?????Certificate Server
• ??Cert Server?Key Server
• ????????????????
• ????Certificate Authority
• ??Public Key Infrastructure
• ?????????????
• ????????????

32
4.3??????
????
?????? ????? ?????
????
?????? ????? ??
????
????
????
????
??? ??? ???
?????? ?????? ?????
????
????
???? ????
33
4.4??????
???? ????
????
?????? ??????
????
????
????
????
????? ?????
????? ?????
???? ????
34
4.5??????

• ????
• ????
• ???????????????????????
• ????????????????????

35
4.6????

• ??????????????,???????????????????
• ???????????????????
• ?????????????????,?????????????????????(CRL,Certif
  icate Revocation List) ,????????

36
5.?????????

• SSL
• SET
• B2C????????

37
5.1SSL(Secure Sockets Layer)??

• ???????????,???????SSL?????????,?????????????????
  ?SSL????,??????????????TCP/IP????,?????????
• ????????????,???????????????????

38
SSL??
?????????TCP/IP???????????????SSL?,???????????????
??????????
TCP/IP
TCP/IP SSL
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5.2SET

• ????????(Secure Electronic Transactions, ??
  SET),?? VISA ? MasterCard ????????????????????????
  ????????????,??????? ????????????
• ???????????????

40
SET??
1.????
2.???????????,????
3.?????????
???
????
8.??????
4.?????? ??????, ??????
7.???? ??
????
????
????
6. ????
5.????
????
41
SSL v.s. SET
42
5.3??????-B2C????????

• 2003?3???????????867??,????38,????????,??????????
  ???????57?59??????1-3?,????????????(???ECRC)
• ????,???????????????????????(????47) (???MIC)

43
??????-B2C????????(?)

• ????????????????????????????????????????B2C???????
  ??????B2C???????????????,?????????????,???????????
  ???40,??40?????,???63????????

44
B2C????????
???? ??????????
45
????

• ????????????
• ??????????????
• ???????????????
• ????(????????)?????(??????) ??????(?????????)
  ?????(HyPOS EZ??????) ?????(e-Coin)
  ?????(OK!Payment??????) ???????(TWPay??????)
• ?????????????
• ???????