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发表于 2010-1-19 19:59:57
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tea.cpp
1 #include "tea.h"
' M% A' E& C2 @4 K 2 #include <cstring> //for memcpy,memset 2 I( {3 D3 _4 J1 j) k8 r. ?
3 5 Y: f# b$ z; Y+ M$ {2 ^0 H- g
4 using namespace std; # k# p8 A2 ?; ? c+ `6 [ v$ z
5 ! W# u' N5 Q" m0 J+ C
6 TEA::TEA(const byte *key, int round /*= 32*/, bool isNetByte /*= false*/) 8 |" V h$ r' U
7 :_round(round) ; E4 W+ M! |! y% e2 y
8 ,_isNetByte(isNetByte) { 5 @- o" q( F9 ]2 k! F8 i6 L
9 if (key != 0) . D% t( v) `, I9 C6 q
10 memcpy(_key, key, 16);
) y( a- H5 _ K/ {: c" n11 else
* K2 {2 o0 T2 C# h8 J, P( [8 g$ F12 memset(_key, 0, 16); 8 _5 P: [' K5 R* q
13 }
# k# S1 D2 N4 i/ k: q! g14 5 l* u7 x, y$ R
15 TEA::TEA(const TEA &rhs)
, W% a8 K/ S2 D2 ~16 :_round(rhs._round)
( n6 u+ Y1 {0 d( [17 ,_isNetByte(rhs._isNetByte) { + {: l' {# k3 L: V
18 memcpy(_key, rhs._key, 16); : W, W' ~7 o* {! s: }. s
19 } ( Q2 Y# B: o! h, J7 ?( Z2 s
20 ) ]) V8 x5 E6 F$ q Z# P
21 TEA& TEA::operator=(const TEA &rhs) {
2 t9 v0 {# S J/ r6 C' s+ r& b22 if (&rhs != this) {
- j/ S9 z$ T) ?+ o5 T23 _round = rhs._round; + L3 h2 |& C4 l% P( M# R# v
24 _isNetByte = rhs._isNetByte; + A6 N$ }; Y; | w$ P0 ?2 j
25 memcpy(_key, rhs._key, 16); 9 e* d* N" u) o1 S/ \, p% b7 O& J
26 } 5 b* t6 s9 r. l$ b; M
27 return *this; 0 ~" ?1 h, P$ }1 R
28 } % D# u7 e" ^5 q* D \
29 4 L( e4 U; Z# d( D/ u }
30 void TEA::encrypt(const byte *in, byte *out) {
" d- [1 J5 G# p1 U% B& p4 D1 l31 encrypt((const ulong*)in, (ulong*)out);
o, _) h8 F5 o# d# V+ Z32 } 1 j1 W1 I! V2 d& J5 `' q
33 ( l. y0 m4 U" I, E
34 void TEA::decrypt(const byte *in, byte *out) {
6 g% T# `" @0 H9 `* F- B35 decrypt((const ulong*)in, (ulong*)out);
" U3 K. u: @2 O; C2 l' |36 }
% H( f8 i4 s( U5 G& R: E, Q( G37
* y$ M- j1 t% ?" @' p38 void TEA::encrypt(const ulong *in, ulong *out) {
$ ]6 {& q* R! R39
, u" e* _# c5 f$ C% P* [40 ulong *k = (ulong*)_key; % B( O, u' M r
41 register ulong y = ntoh(in[0]);
- s% y5 i9 ? A& h$ {( o: a0 O42 register ulong z = ntoh(in[1]);
& h( g1 z% u: P# x43 register ulong a = ntoh(k[0]);
- m7 b" z; ] j3 Q" Y* q8 d; O44 register ulong b = ntoh(k[1]);
- z* o: |8 m$ y7 J45 register ulong c = ntoh(k[2]); ( \" D5 P+ f. M4 m9 b; _( l. B
46 register ulong d = ntoh(k[3]);
) V1 `( Q& _5 @% ^+ v; w1 w47 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
; ]. Y) r. V3 F& K) ?48 register int round = _round;
) ^0 l5 D( }( O4 [. g49 register ulong sum = 0; 2 g, R( a: ]$ d/ @ C
50 + ~9 E) E, o; P, N
51 while (round--) { /* basic cycle start */
5 G& z5 J1 A0 D# u52 sum += delta; 9 D6 N) C- w; j7 p8 ~+ ]- H
53 y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b); / @( B, D' e' S
54 z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
, _% Y% ^9 V2 c2 s' N7 ~55 } /* end cycle */
' P% |5 m6 C7 H5 V56 out[0] = ntoh(y);
3 C- a- w6 k# c" t( ^/ s& ~57 out[1] = ntoh(z); 2 I4 L/ \7 u+ h* p& i# K
58 }
8 X6 o4 P, O ?- W6 f" q- o+ S# n4 x59 5 `. A3 V. a1 ]3 w |5 }! y
60 void TEA::decrypt(const ulong *in, ulong *out) { 5 L% k* ?- l2 n- Q4 [; B" M
61
9 X& J% C; J: ^! D+ ]4 L: `62 ulong *k = (ulong*)_key; * H. C2 N' Z, W5 B3 Q! z
63 register ulong y = ntoh(in[0]); $ B2 d# E5 }' ?2 j) e$ E
64 register ulong z = ntoh(in[1]); ! r. e5 h- r3 @4 A" Z: i: p8 ^
65 register ulong a = ntoh(k[0]); ( P( D4 b: u9 z& d4 q
66 register ulong b = ntoh(k[1]); 9 |- C. c) j6 G( D9 Q: w1 R# }
67 register ulong c = ntoh(k[2]);
0 ]* A3 j- a( F68 register ulong d = ntoh(k[3]); : R5 ~. b% s5 A' f
69 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
% E* R* }1 \ g5 F" O" ~0 B, `- w70 register int round = _round;
9 H1 Y( M$ f2 ?' s' ]. h! H71 register ulong sum = 0; . D+ z9 Y4 C$ \9 o3 i" X: y; X& S" Q
72 * [0 v8 G; _4 T
73 if (round == 32) B3 J! Q0 o4 ?7 L# U
74 sum = 0xC6EF3720; /* delta << 5*/ 2 @6 W4 T9 p' \, e2 z
75 else if (round == 16) # A4 X6 L4 s1 Y3 ^7 V! B# z
76 sum = 0xE3779B90; /* delta << 4*/ t: q2 Z& Y) Y" Z) l* ^+ T
77 else
2 q) e l/ Q, Q& M0 U" A' N78 sum = delta << static_cast<int>(logbase(2, round));
$ P9 `# w# J, G79
6 ~' ^4 I& d" A$ \80 while (round--) { /* basic cycle start */
* }! u5 E; m% { k81 z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); / H' h! l4 {. {# {8 U3 z1 |
82 y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b); + A- k4 d7 \+ m) N/ A4 c) e+ ?
83 sum -= delta;
$ e: X6 ~- K1 p84 } /* end cycle */
) t# X+ X$ O- H6 g85 out[0] = ntoh(y);
1 ]) X/ l" J$ u4 B" J5 _9 D86 out[1] = ntoh(z);
4 U+ S B9 p* \. v0 v: P2 z0 I) r87 }, u2 n' _1 ^0 Z9 \$ _( u' N
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需要说明的是TEA的构造函数: 1 a5 \) G2 ]3 o( J, l# Z( u) X; Z. q
TEA(const byte *key, int round = 32, bool isNetByte = false);
. X! f3 R, q3 {+ n1.key - 加密或解密用的128-bit(16byte)密钥。
$ l6 e# P; K7 ^; ~+ }$ \2.round - 加密或解密的轮数,常用的有64,32,16。 ! i) U! f* `$ e+ Y2 U4 Q
3.isNetByte - 用来标记待处理的字节是不是来自网络,为true时在加密/解密前先要转换成本地字节,执行加密/解密,然后再转换回网络字节。偷偷告诉你,QQ就是这样做的!
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最后当然少不了测试代码: |
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