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发表于 2010-1-19 19:59:57
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tea.cpp
1 #include "tea.h"
" ?& U2 ~% e7 K 2 #include <cstring> //for memcpy,memset
8 ^( W0 K5 S/ h/ q 3 4 _9 `; h5 a0 L4 \- g' H1 S
4 using namespace std;
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" f% k$ b C+ c 6 TEA::TEA(const byte *key, int round /*= 32*/, bool isNetByte /*= false*/) , `3 G9 T' }5 f# V+ k0 q& \
7 :_round(round) , y" i. H' C+ E3 }, x$ @) R0 S
8 ,_isNetByte(isNetByte) { + c) F+ K$ A- s% W# m# K" I
9 if (key != 0)
4 q/ F) E" \6 Z* H5 Q3 F7 b10 memcpy(_key, key, 16); 7 m+ Q* Y# R( L! C/ l9 S# P
11 else
e z& C5 e7 N# n/ l12 memset(_key, 0, 16); 4 K% I0 j+ ?( F8 B+ b {% L
13 } ) C2 X5 _+ [ \: r! S/ I
14
* m. E; J& _8 q+ e# t2 B% Z$ V15 TEA::TEA(const TEA &rhs) 9 O+ O6 C) l ^) g1 _
16 :_round(rhs._round) 2 ?, o `4 Y2 ?, d4 |' h# f
17 ,_isNetByte(rhs._isNetByte) {
% b0 _3 A( |2 m0 S% r18 memcpy(_key, rhs._key, 16);
6 g* \8 l& E4 t2 g; U) A1 \19 }
/ C5 E! Z1 c4 @* R" \20
# P# S1 D' ~, a% S21 TEA& TEA::operator=(const TEA &rhs) {
[* z2 N# }# q8 ^* M22 if (&rhs != this) { ) Q% Y' n9 E) U7 i7 s% q6 Z
23 _round = rhs._round; 2 p' d0 f4 ?0 k. C9 b& i
24 _isNetByte = rhs._isNetByte; 4 Y0 |( P" A7 f+ {3 L
25 memcpy(_key, rhs._key, 16);
3 ?$ ~( C- t% {26 } # `% O7 {0 H: g" X$ a
27 return *this; 4 M' d4 N- n8 _) i" @& R# G' U% v5 j
28 }
2 t# l" r. H, x; B3 d# _) y6 H* T29
* a% ]( d4 Z, b* [( `0 p30 void TEA::encrypt(const byte *in, byte *out) { 8 T5 d7 M+ _* \& ]; l0 H
31 encrypt((const ulong*)in, (ulong*)out);
# U$ R1 o- l6 N7 F2 E! s$ L32 }
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34 void TEA::decrypt(const byte *in, byte *out) {
6 `7 F7 [5 l: z7 S* p35 decrypt((const ulong*)in, (ulong*)out); # Y: z/ b+ \5 ~5 j" q. g6 ?
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37
0 l4 `, o$ E( A2 l1 @38 void TEA::encrypt(const ulong *in, ulong *out) { % r; H1 @8 D. S* {, Y
39
, v+ |# @8 x. X* A; u5 F0 n40 ulong *k = (ulong*)_key; ( t2 p; `3 w' h5 @% }5 c4 ?
41 register ulong y = ntoh(in[0]);
4 F; L! p' I1 g3 m4 N$ q1 f" Y4 d& t4 K$ z42 register ulong z = ntoh(in[1]);
$ G9 v4 E9 @& r `6 x5 c; z8 T: [43 register ulong a = ntoh(k[0]);
6 _4 I$ ]( ~& R% z* o* S44 register ulong b = ntoh(k[1]);
7 v% s. d5 r: ]9 W* O45 register ulong c = ntoh(k[2]);
1 _$ K. B4 b3 |+ H$ |46 register ulong d = ntoh(k[3]); 7 U; N& H5 X# r% v/ w( Y
47 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */ / f* ?7 W4 @: L8 {, {; d
48 register int round = _round; 1 l' q! |" q8 B+ U3 e
49 register ulong sum = 0; 9 m4 J3 g9 l; k
50
5 ` R6 ]" ^' i7 e* T% e51 while (round--) { /* basic cycle start */ 9 M4 O. ^- a$ V! z
52 sum += delta;
! p$ A8 ?8 r' A( U8 A8 z. k53 y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
" _( y. Q, O9 @1 h; C0 w. i54 z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
/ s6 n3 G3 w4 O1 z- s' d2 q55 } /* end cycle */ 2 `1 o6 v/ M! I' V% ?5 z
56 out[0] = ntoh(y); ' h" k) f% v: F$ k4 U
57 out[1] = ntoh(z);
- X3 d5 C$ J/ k/ y( o! \58 }
1 }, p9 u7 j: k: Y4 P* T59 : a# ?7 }# G/ U! @/ K2 }0 p
60 void TEA::decrypt(const ulong *in, ulong *out) {
/ b X W. C1 K3 Z" e61
9 E3 l, w$ x, b. Z/ O; l62 ulong *k = (ulong*)_key; 7 B( c+ r% _0 ?
63 register ulong y = ntoh(in[0]);
7 W, T8 N" a4 `! P2 C; a64 register ulong z = ntoh(in[1]);
( r5 b) I0 B* ]0 q5 U65 register ulong a = ntoh(k[0]); . [' k" d* ~, z; p
66 register ulong b = ntoh(k[1]);
0 o2 f* x, r& n, U J. M7 m9 I67 register ulong c = ntoh(k[2]); + Q: @- P7 L/ n
68 register ulong d = ntoh(k[3]);
% l; @" u. p- P+ X6 e69 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
3 s# b6 P! B5 p; s" U+ R2 z70 register int round = _round;
8 U3 A6 P l; J1 R71 register ulong sum = 0; # a8 `1 E0 Y- P$ t, U4 J
72
8 ?+ \4 t9 Y9 n) y1 m ~+ }73 if (round == 32)
/ c4 u( {0 k, D2 s74 sum = 0xC6EF3720; /* delta << 5*/
+ A5 K% [9 T0 M X75 else if (round == 16) - q2 o! W+ Y, l1 s5 J
76 sum = 0xE3779B90; /* delta << 4*/
# N/ z- f5 p9 Z# c2 h" A77 else ) x6 c% K% }) B2 ]* [
78 sum = delta << static_cast<int>(logbase(2, round)); $ Z$ G- G2 }6 a( O+ ^
79 , f& H9 x, b& A3 _
80 while (round--) { /* basic cycle start */ 8 K) M8 H6 k/ l) \
81 z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); ' }, q9 b. V$ U& H. a
82 y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
0 m9 O- v( B+ o$ g X m+ k83 sum -= delta;
4 B4 ?7 B% D- Q9 V84 } /* end cycle */ # i% c2 S. i$ u1 c8 t" d
85 out[0] = ntoh(y);
5 m* I! ^& t( a6 G) \% B86 out[1] = ntoh(z); $ T; y7 K( D7 o7 j' A' I2 N& k# k! ~
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需要说明的是TEA的构造函数:
- X+ w) @( s! xTEA(const byte *key, int round = 32, bool isNetByte = false);
- _) u9 X/ y% L7 n5 x; }, q1.key - 加密或解密用的128-bit(16byte)密钥。
5 y$ B5 {" z% q0 b$ L2.round - 加密或解密的轮数,常用的有64,32,16。 / G7 P& b! X3 z! i: W
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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$ E* i0 T. `. N" B最后当然少不了测试代码: |
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