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发表于 2010-1-19 19:59:57
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tea.cpp
1 #include "tea.h" " p" w" p) y; H/ m$ f0 }* \1 ?" b
2 #include <cstring> //for memcpy,memset 4 w W4 a" S7 o% W" K+ Q
3 + {0 B9 C! e: y3 f6 f) |5 j; u9 q
4 using namespace std;
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% ?1 [, @ P y( Z# z 6 TEA::TEA(const byte *key, int round /*= 32*/, bool isNetByte /*= false*/)
1 j* |& T X3 t7 b 7 :_round(round) ; Z* l7 c" T! H! l
8 ,_isNetByte(isNetByte) { ( v& I* v* Y+ ]+ q
9 if (key != 0)
, {/ _$ S7 P4 ^3 z2 @10 memcpy(_key, key, 16); ; o @' B: n/ j
11 else
; h/ }' ]/ a/ P1 z12 memset(_key, 0, 16);
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14 & A& O; P! G3 U& E
15 TEA::TEA(const TEA &rhs)
* I- G' b* [; O5 b+ }16 :_round(rhs._round) 5 H8 |5 o2 V. D5 K q: G: d9 X
17 ,_isNetByte(rhs._isNetByte) { 3 z" C1 P( i/ k5 l, S6 u" `: n) e! e
18 memcpy(_key, rhs._key, 16); 9 K2 B2 G) o0 ?3 ~- ^
19 } ! f' M& g6 S6 k
20
& @' Z0 a! ?/ M( s4 R4 d6 K21 TEA& TEA::operator=(const TEA &rhs) {
6 _ z7 y! s0 z- D6 I5 m22 if (&rhs != this) {
9 K* k& J( Q) S23 _round = rhs._round; * C' n' n- P# F3 t$ B
24 _isNetByte = rhs._isNetByte; ; \' |- R; O; L: ~' g
25 memcpy(_key, rhs._key, 16); : w% I9 j' T0 H' R8 ~
26 } # O4 Y, e: @7 r: T: m
27 return *this; s; l0 G. |3 R2 ? D$ Z0 S! m
28 }
! G% Z; T! X2 `& s: c' {29 # C" Z9 x7 Z: u6 `5 c0 d. ?
30 void TEA::encrypt(const byte *in, byte *out) { n: G+ Q& [' Z! ~
31 encrypt((const ulong*)in, (ulong*)out);
& h( h3 q4 ]1 @7 u9 h32 } ( f1 o6 ?5 D2 E+ u1 T
33 8 d$ a* l# R4 ~. G
34 void TEA::decrypt(const byte *in, byte *out) { 3 S& l6 t( m6 z; O4 z# M2 I
35 decrypt((const ulong*)in, (ulong*)out);
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37 6 a F5 B) h4 m8 ^9 V4 T2 o
38 void TEA::encrypt(const ulong *in, ulong *out) { 9 w: L- c! I- {& X. H
39
2 g0 j- d/ w: C J40 ulong *k = (ulong*)_key;
" B+ t6 i( q/ s5 L. c5 G41 register ulong y = ntoh(in[0]);
0 c. q z* {: i2 `6 {42 register ulong z = ntoh(in[1]); 1 X+ [$ ~8 w( }1 X0 a( k
43 register ulong a = ntoh(k[0]); . [! p/ K! h+ f9 R5 O
44 register ulong b = ntoh(k[1]);
* o9 M! S4 e- Y; s4 p) V' C45 register ulong c = ntoh(k[2]);
# s/ W3 ]: C* k0 _) x1 _+ P46 register ulong d = ntoh(k[3]); ! N$ P( I! \4 a* U
47 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */ . c/ n! C1 n6 ] N; c: G
48 register int round = _round; ) }% K4 ^* H' z2 E
49 register ulong sum = 0;
0 w# z% ], h0 X$ b50 + E. d6 v/ I$ M/ f5 Q4 b
51 while (round--) { /* basic cycle start */
# X7 L" ^7 F- e1 B1 \2 E52 sum += delta; 6 d$ n* s1 a& F' J$ ~
53 y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
$ T5 l& L* [* M* R6 K54 z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
# D' H* F3 ^8 s, B+ p* Z; P) U& E55 } /* end cycle */ 9 ?3 Q; a% z& Y& V* x, F
56 out[0] = ntoh(y); 3 K9 I1 y4 `- @7 m
57 out[1] = ntoh(z); : _5 P: @/ f: [3 z
58 }
7 ~. J1 s% k2 h59 , s- D2 N. Q' w) L" _) j0 S
60 void TEA::decrypt(const ulong *in, ulong *out) {
2 e# w# z+ r3 L61
& g' b/ V- W) l. Y3 _0 p2 s0 y2 S62 ulong *k = (ulong*)_key;
, F# m' @. B0 j# y$ T- ^( r63 register ulong y = ntoh(in[0]); : F% W8 Y6 ^4 d8 B; h: \; t
64 register ulong z = ntoh(in[1]); 5 K7 ]& F3 e1 I4 H$ d( n$ x/ F
65 register ulong a = ntoh(k[0]);
) D1 d. {* z% }: y3 B, u66 register ulong b = ntoh(k[1]); : @# Y) ?6 I: Y& [
67 register ulong c = ntoh(k[2]); , T- ]8 Y) k2 A \% q; L4 q
68 register ulong d = ntoh(k[3]); 0 k6 q' R1 J6 e. a6 Y% s4 S
69 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
: \1 U: H% j0 d8 ]70 register int round = _round;
' b/ i3 ^" W6 K# J0 W; \71 register ulong sum = 0; 8 p- K) f g( ?; F
72
) ]0 T( e9 d$ { \. D3 K; i( o73 if (round == 32) ( s7 X6 p- A0 k! Y
74 sum = 0xC6EF3720; /* delta << 5*/ 3 p* |4 ~ [( Q3 k- R* I6 ^
75 else if (round == 16)
5 T$ \5 g7 V# k; H& M( s2 G76 sum = 0xE3779B90; /* delta << 4*/
; @6 u3 y. z8 Q m77 else
7 z" {/ D2 a$ K2 n) ^0 |78 sum = delta << static_cast<int>(logbase(2, round));
# H/ y; ?/ y( u79 : U; f v' m9 G, S* n: s1 e3 P
80 while (round--) { /* basic cycle start */ . G( W" W7 j* [8 U
81 z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); ! d2 D8 F# A& N) [, g# p+ v
82 y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b); ) O7 `" z; D6 e+ N+ \$ Q
83 sum -= delta;
# [7 f8 J' Q9 W$ o$ a84 } /* end cycle */
! i( P8 w' }) n- K/ ]1 q85 out[0] = ntoh(y);
4 M9 N9 | ~9 o4 ~1 o# `86 out[1] = ntoh(z); & W! _+ y5 m7 @* z1 ?" n/ K
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需要说明的是TEA的构造函数: 6 ^3 G, x# M2 \3 k% s, p l
TEA(const byte *key, int round = 32, bool isNetByte = false);
Y7 B0 s; M. j- L) b1.key - 加密或解密用的128-bit(16byte)密钥。 ! z' ]+ U5 ^5 M7 q+ m5 P9 V
2.round - 加密或解密的轮数,常用的有64,32,16。 " ~3 w5 |/ |$ }( E0 Q2 \6 Z
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! F5 |( a: c _" w/ s
; ?0 w6 P7 g G& q4 }9 f最后当然少不了测试代码: |
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