文档介绍：应用密码学与PKI介绍
1
目录
对称加密技术 ↓
more OP-MODE ↓
公钥密码技术 ↓
认证和Hash算法 ↓
数字签名 ↓
PKI原理 ↓
PKI应用与实验 ↓
案例分析
2
Mode
CN-1
Dec
PN
CN
X
+
X
CN
Dec
PN-1
+
K
CN-2
0
K
26
DES标准文档
FIPS 46-3, Data Encryption Standard (DES)
DES实现
OpenSSL
Microsoft CryptoAPI
27
DES应用实例分析
/etc/passwd|shadow
username:Npge08pfz4wuk:503:100:FN:/home/username:/bin/sh
char *crypt(const char *key, const char *salt);
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Zip cracker sample
Advanced ZIP Password Recovery statistics:
Encrypted ZIP-file:
Total passwords: 2,091,362,752
Total time: 6m 58s 725ms
Average speed (passwords/s): 4,994,597
Password for this file: 7uee23
Password in HEX: 37 75 65 65 32 33
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DES已不再安全
使用穷举密钥攻击，如果每秒能尝试100万个密钥(70s)，则约需要1000年才能枚举完所有2^56个密钥。
使用特制的专用硬件芯片，结合互联网分布式计算，最快曾经在1天内攻击成功。
30
“Deep Crack” Hardware Cracker
Developed by the Electronic Frontier Foundation
Cost
$80,000 design
$210,000 materials (chips, boards, chassis etc)
Chip by Advanced Wireless Technologies
40 MHz /16 cycles per encryption = million keys/s
24 search units per chip，64 chips per board ，29 boards into 6 cabinets
90 billion keys/s，solved RSA’s DES-III in 22 hours
Jan 18, 1999
37,000 search units
. Distributed Net’s 34 billion keys/s
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3DES
关于2DES
关于3DES
32
AES
“Rijndael”
分组128bits
密钥128bits(也可192/256)
常量S盒
使用有限域GF(2^8)构造
1+9+1轮
FIPS-197
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AES Overview
34
1 Round
35
S-box in AES
x/y 0 1 2 3 4 5 6 7 8 9 A B C D E F
0 63 7C 77 7B F2 6B 6F C5 30 01 67 2B FE D7 AB 76
1 CA 82 C9 7D FA 59 47 F0 AD D4 A2 AF 9C A4 72 C0
2 B7 FD 93 26 36 3F F7 CC 34 A5 E5 F1 71 D8 31 15
3 04 C7 23 C3 18 96 05 9A 07 12 80 E2 EB 27 B2 75
4 09 83 2C 1A 1B 6E 5A A0 52 3B D6 B3 29 E3 2F 84
5 53 D1 00 ED 20 FC B1 5B 6A CB BE 39 4A 4C 58 CF
6 D0 EF AA FB 43 4D 33 85 45 F9 02 7F 50 3C 9F A8
7 51 A3 40 8F 92 9D 38 F5 BC B6 DA 21 10 FF F3 D2
8 CD 0C 13 EC 5F 97 44 17 C4 A7 7E 3D 64 5D 19 73
9 60 81 4F DC 22 2A 90 88 46 EE B8 14 DE 5E 0B DB
A E0 32 3A 0A 49 06 24 5C C2 D3 AC 62 91 95 E4 79
B E7 C8