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发表于 2010-1-19 19:59:57
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tea.cpp
1 #include "tea.h"
6 `. g' o( \; {# D. L! a 2 #include <cstring> //for memcpy,memset , k R, }. f J) U; e
3
7 J5 }: z6 p( ? 4 using namespace std; 2 x' m3 G+ ?( w* N
5 2 c/ O" W9 h; |; ]' Q; A# W% l
6 TEA::TEA(const byte *key, int round /*= 32*/, bool isNetByte /*= false*/)
0 d5 J& H4 W; q( a 7 :_round(round)
2 g9 A1 ?& v F! S8 v 8 ,_isNetByte(isNetByte) {
. R: }! P' i* A+ ? 9 if (key != 0)
* Q$ |" j. I8 g10 memcpy(_key, key, 16); 7 ], n# ?3 `: x8 c# X$ y
11 else
. E4 L& o" L* ^! ~: T5 [; L: n' Y12 memset(_key, 0, 16); - P9 G' R( g7 w- o/ ]) R, H
13 }
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15 TEA::TEA(const TEA &rhs)
) b; t0 o* j! a. S3 e) z! {16 :_round(rhs._round) ' Q2 q! e% s- L5 l/ }2 r* _* L
17 ,_isNetByte(rhs._isNetByte) {
2 p2 L" r9 H, d- t7 L, U; {3 F18 memcpy(_key, rhs._key, 16); g. D! ?7 _; P% M
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20
% X# T2 p$ i+ V& k- o21 TEA& TEA::operator=(const TEA &rhs) { ; e% J% o8 q8 H1 P- r+ S \9 ?
22 if (&rhs != this) { - J1 f2 K7 ?$ A
23 _round = rhs._round; ; O! a0 L1 Q7 ?/ r& a
24 _isNetByte = rhs._isNetByte; 4 t9 ~" K+ O2 w. I
25 memcpy(_key, rhs._key, 16);
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27 return *this;
% ^! z/ _& ?! b h( o28 } 1 q1 K" A% ?2 A2 d3 {/ T4 {, q
29
: Q; s5 T* b& b# V* F, N30 void TEA::encrypt(const byte *in, byte *out) {
) w- {4 C. u" h0 t H/ Z4 N% ?31 encrypt((const ulong*)in, (ulong*)out); $ I( ?/ T& v' Q3 R+ I
32 }
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# J) t; ], @3 o y9 ?% y7 }34 void TEA::decrypt(const byte *in, byte *out) { / S% {, {% t, E' S& Z0 }, s3 m
35 decrypt((const ulong*)in, (ulong*)out); , U6 c8 h5 e' q, W4 V/ g% F- E6 |
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38 void TEA::encrypt(const ulong *in, ulong *out) { " ~( {1 A) d2 G8 e( h% @7 R( T
39
* y7 u6 ?5 [" n; B* ?$ t40 ulong *k = (ulong*)_key; 2 T. ~8 \9 h( N" k5 o
41 register ulong y = ntoh(in[0]); 6 d3 X& g }' i# Y
42 register ulong z = ntoh(in[1]);
3 x5 u" f! K" o43 register ulong a = ntoh(k[0]);
: W# [: G: e# t+ Q44 register ulong b = ntoh(k[1]);
" T+ b3 ^7 V) u" G0 S1 p45 register ulong c = ntoh(k[2]); # U7 N3 n& {* X& x' a5 F
46 register ulong d = ntoh(k[3]); 1 M# H1 d, M9 `
47 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
/ [2 _" R7 h( ?2 N4 z48 register int round = _round;
( K# z3 r0 i7 G+ c5 l/ K( M9 n8 U49 register ulong sum = 0;
: b2 ~2 Y$ V7 U ?3 l W50 & a' b' R) S0 M* @3 N/ J+ |
51 while (round--) { /* basic cycle start */
5 |% k1 R/ ~; |1 o, S& i( l52 sum += delta; # b, l7 {0 x$ b) c/ F* b4 c# I% f
53 y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b); ) V. ~) W1 F, a1 p$ |& \/ N5 I- ]" v
54 z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); 1 o: [ c- N9 M( l0 d: k# X/ q5 M
55 } /* end cycle */
! {& `7 O" C; A, ~56 out[0] = ntoh(y);
8 |! A& }8 m2 t57 out[1] = ntoh(z);
! a4 @1 j; P% _$ q) ?58 } , C/ D5 k! A$ N; x
59
' I7 M8 C2 P# }, l; e% ^) k60 void TEA::decrypt(const ulong *in, ulong *out) {
) d/ E2 `0 o% O' Y5 W; `6 f+ K8 G61 ) ~% u7 ?; N! w* c
62 ulong *k = (ulong*)_key; / L [1 P9 w% |( h
63 register ulong y = ntoh(in[0]);
$ l3 {4 `8 D. M ]: O64 register ulong z = ntoh(in[1]);
( @; v" f: f: Z65 register ulong a = ntoh(k[0]);
3 ]* l: {2 Q) }& ?" P- i, l66 register ulong b = ntoh(k[1]); 0 V3 _+ c& g# i/ n- f4 _1 ~8 V
67 register ulong c = ntoh(k[2]); 1 L) z' `2 v2 F- w K' F- {
68 register ulong d = ntoh(k[3]);
4 r/ B: n* T% r( k# |2 t) R69 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */ S. w( A& x- w# `3 W
70 register int round = _round; " {7 t6 G* p. t+ j9 M
71 register ulong sum = 0;
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73 if (round == 32) 0 o7 w3 A! K' N8 c: F; Q
74 sum = 0xC6EF3720; /* delta << 5*/ 3 p h2 b6 g5 L
75 else if (round == 16) 8 g4 m. x s& G! U0 U
76 sum = 0xE3779B90; /* delta << 4*/ ( E. b9 [& J- X; V1 x. f! F" y9 R1 f
77 else
. a, q; e) n9 l* M$ N78 sum = delta << static_cast<int>(logbase(2, round));
" m% u4 e6 d5 O8 s+ }79
- O* O4 j' z1 i3 f+ ]80 while (round--) { /* basic cycle start */ ) X3 P$ H) P' @) W& ?# j1 K) c
81 z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); 0 M/ y7 ]0 b* f
82 y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
. d5 m# }' A; S" f" T( ^83 sum -= delta;
$ t F. f$ [' k3 q7 M! ~84 } /* end cycle */ , D* f, ?6 G5 B8 F
85 out[0] = ntoh(y);
% B, }7 c; ?: K$ ?: P. d5 F. Z86 out[1] = ntoh(z); " e, R1 S3 M- u, H
87 }
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需要说明的是TEA的构造函数:
. }. p8 m8 U0 N2 k% u: x+ qTEA(const byte *key, int round = 32, bool isNetByte = false); ) }0 o+ l1 ^2 T% ^/ b
1.key - 加密或解密用的128-bit(16byte)密钥。 ; i& u4 E. h3 ~# C/ w$ }
2.round - 加密或解密的轮数,常用的有64,32,16。 & V/ |6 N; @, q- A9 n6 J& Y0 P0 L
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! : w) H" |$ _5 o- T( Z
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最后当然少不了测试代码: |
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