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发表于 2010-1-19 19:59:57
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tea.cpp
1 #include "tea.h"
2 D% } \0 B) {: V$ l# @ 2 #include <cstring> //for memcpy,memset
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4 using namespace std; ) w; @( X3 o$ o4 Q2 e7 y
5
" o3 U) c2 w4 S5 K+ r9 M. [# a& O 6 TEA::TEA(const byte *key, int round /*= 32*/, bool isNetByte /*= false*/) , A2 c u8 q+ C
7 :_round(round)
3 b- y3 c$ j/ o! D5 I 8 ,_isNetByte(isNetByte) { 2 V# F, E9 t+ j- t' G* ^ w' b/ C
9 if (key != 0)
* `5 _* d3 o# g& R5 C1 B10 memcpy(_key, key, 16);
/ \: Q- b% b, w ~! s; z `0 f9 [11 else
* F. `, t/ @, o9 q1 {12 memset(_key, 0, 16); % |: M# G9 P4 B9 M- b4 ^) N" T) [
13 }
4 \: p. ~- ]3 `# b( C v8 d4 H; I; l14
1 F& ]- s+ O2 G+ Q15 TEA::TEA(const TEA &rhs)
- u1 n/ o1 }6 P) u+ h8 j" B0 }16 :_round(rhs._round)
, Y1 x) k& i, M) _% [6 H! |1 s17 ,_isNetByte(rhs._isNetByte) { ' o* K' f4 @$ C- }
18 memcpy(_key, rhs._key, 16); " P/ Z1 `9 R# b/ J P! Q) N# P
19 }
" B1 \* ^5 T2 C, y+ u" v u20
! F) c0 F( x1 j1 x21 TEA& TEA::operator=(const TEA &rhs) {
7 E& e# L+ u' m1 m L* N( C2 e22 if (&rhs != this) {
% d. D0 G0 `' k; s23 _round = rhs._round; $ i; B% H) o8 l- w7 p5 v
24 _isNetByte = rhs._isNetByte; " a/ r& l. i+ E& K+ @7 k
25 memcpy(_key, rhs._key, 16); 4 G0 J& j% E+ J0 w6 m
26 }
+ B# G7 l) T+ l$ M2 H9 H27 return *this;
# i0 A' s& Y0 w/ P3 ~3 m+ m8 J# j. V28 }
. ~# Y# m6 X, F9 c29 0 L; k- V! S# m, C3 i a4 N9 I9 i$ }
30 void TEA::encrypt(const byte *in, byte *out) {
- H$ K$ m) G2 [) j9 n! S31 encrypt((const ulong*)in, (ulong*)out); 7 f& G5 \ ]: V7 v3 d6 {) }
32 } $ ]) }7 K' k/ G$ [. g8 F) E: U
33 ( y% O. a- B7 t( Z- F7 ?
34 void TEA::decrypt(const byte *in, byte *out) {
9 f- w |( ]; T8 s1 ~( D8 g35 decrypt((const ulong*)in, (ulong*)out);
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37
$ T8 |5 K* i; a: L3 m, l+ T- w38 void TEA::encrypt(const ulong *in, ulong *out) { , J) S+ V/ p5 U$ J( N7 O
39 ' B) H3 L( [1 d$ s$ q5 a
40 ulong *k = (ulong*)_key;
: U+ l& Q3 }! M. [. b41 register ulong y = ntoh(in[0]);
' b1 a. Z! l1 G# d y42 register ulong z = ntoh(in[1]); # I9 X1 v" b5 B- P" W) T
43 register ulong a = ntoh(k[0]);
$ l3 s2 ]" I' b5 U6 y44 register ulong b = ntoh(k[1]); ! w$ G( n) ^9 Y; \1 U9 Z8 P0 ^
45 register ulong c = ntoh(k[2]);
: @( |9 _* D6 ]! \8 D6 U46 register ulong d = ntoh(k[3]); T! Q) w5 B- h! g6 G6 O$ w
47 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */ , `2 z6 f) R& N, I) M
48 register int round = _round; ! a7 [) b1 E+ d) n
49 register ulong sum = 0;
- @0 h* Y6 D, W& O# [50 9 s5 }7 H4 q" M0 E) }* R
51 while (round--) { /* basic cycle start */
1 t5 K- h& [3 F52 sum += delta; % e7 A7 v& m! }7 j6 z) y
53 y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b); 3 ~2 K' C; R9 M& ?
54 z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
% P' {/ ~# p* _7 ~) N3 z9 L55 } /* end cycle */ % C4 y% R% j: v1 ^1 g7 M
56 out[0] = ntoh(y);
# d9 e; G$ {( M/ S57 out[1] = ntoh(z);
) k9 U+ v( o- e9 M! m" F/ e58 }
, R; H q+ [2 j! x! V: G59
. h( d' D4 I1 f7 C60 void TEA::decrypt(const ulong *in, ulong *out) { - Y' y4 n1 G k7 ^1 I
61 : H, j+ Y/ X5 ^/ ?
62 ulong *k = (ulong*)_key; 4 q8 w: ^$ v3 D* n
63 register ulong y = ntoh(in[0]); ! H3 a8 r9 p6 s7 C
64 register ulong z = ntoh(in[1]);
4 w( d% B! C+ R1 A4 w0 @65 register ulong a = ntoh(k[0]); 9 W+ g& y, [1 ^8 ~& w2 I
66 register ulong b = ntoh(k[1]);
5 e" a( g$ i Y* F8 D67 register ulong c = ntoh(k[2]); ' I) ]0 ~3 h- Z+ x& ^
68 register ulong d = ntoh(k[3]);
; h! I6 M) z7 C) J9 n69 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
( ? g3 d- ? u2 ^) C# [( _& X70 register int round = _round;
: j" y# B( h3 |! z1 g3 t6 z71 register ulong sum = 0;
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73 if (round == 32) * [- ~& x! L" B7 v
74 sum = 0xC6EF3720; /* delta << 5*/
! d8 U) G) q+ i4 q$ w75 else if (round == 16)
7 z. l S* E. f, V3 I76 sum = 0xE3779B90; /* delta << 4*/ 2 T+ C" P) y2 ^: j
77 else
9 e* X# ?; E4 o# I78 sum = delta << static_cast<int>(logbase(2, round)); % {" t9 }% c# ~! E, L
79
( ^9 Q# O5 {4 D6 _1 l1 A+ B80 while (round--) { /* basic cycle start */
" F4 Y+ A% S: N$ l/ ?# y- i$ {5 E81 z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
* w( s% n) U! _" J/ [82 y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
* h) G- m# Z: u' m3 o7 Y2 a83 sum -= delta; ; Z$ h; [4 O: _$ Y
84 } /* end cycle */ ) F( W8 Q0 O O- }
85 out[0] = ntoh(y); 9 w6 [1 a( C5 t% u" D r
86 out[1] = ntoh(z); % t- B: x( P' q5 [. e" w
87 }8 t! h/ u' I' O6 q/ s
% i* X) R2 [: I' U4 v( J需要说明的是TEA的构造函数:
# X3 ]5 [; \6 D- aTEA(const byte *key, int round = 32, bool isNetByte = false);
( u% X+ g: H5 O, q1.key - 加密或解密用的128-bit(16byte)密钥。
! C0 }8 c" V) U) }/ Y6 Y- r2.round - 加密或解密的轮数,常用的有64,32,16。 . E6 o! t; b! C4 _% Z3 j) r; v' ]
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! 8 {6 h) c d2 s
0 @$ Z) g4 u: d/ K+ Z! n2 b最后当然少不了测试代码: |
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