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发表于 2010-1-19 19:59:57
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tea.cpp
1 #include "tea.h" 4 _4 x% a- z$ v, m4 B# } J
2 #include <cstring> //for memcpy,memset : p% s3 q5 k/ z& i' `/ M2 M8 X
3
1 T; y) T7 N* o) Q9 T 4 using namespace std; , c/ A( C& ?: a0 ^8 K0 A# m& w" T1 k, g
5
( t) W) K; N* c! I 6 TEA::TEA(const byte *key, int round /*= 32*/, bool isNetByte /*= false*/) & |1 o3 y( x- `; V1 g2 V- M
7 :_round(round)
& T' u9 {* K }' C5 K3 m# _ 8 ,_isNetByte(isNetByte) { " K/ R* c a: d: S, _# i
9 if (key != 0) + M, G$ c4 a0 c0 d# M
10 memcpy(_key, key, 16);
. ~# q+ P8 s/ ~6 ~& f: V# t7 l2 D11 else
4 J( {6 @1 ^3 s+ l12 memset(_key, 0, 16); 8 J' r* L2 C( g) T, J/ [8 d( T; }, B) ^
13 } ( s8 c1 H' o3 k6 u M
14 6 T* ]" R9 r* O6 q" w; Q
15 TEA::TEA(const TEA &rhs) . q/ ~8 S- U T# D$ Y
16 :_round(rhs._round)
{8 r- b, ?: m8 l17 ,_isNetByte(rhs._isNetByte) {
* Y5 a$ ?/ y6 ]& H5 A: Y- R( j: V18 memcpy(_key, rhs._key, 16); " C$ M3 `: d4 i
19 }
) C: z9 n. V3 t4 m: [7 b20
3 m2 Y0 s8 _, e* S21 TEA& TEA::operator=(const TEA &rhs) { 6 U" Q2 l1 U; M
22 if (&rhs != this) { # c. K, v4 [7 J% R) m- d3 M, q. B
23 _round = rhs._round; , j+ t. A! L8 f5 y
24 _isNetByte = rhs._isNetByte;
4 c0 B! B0 M" L0 I5 c25 memcpy(_key, rhs._key, 16);
& q$ ^# F9 R: {- l' k2 j8 q) u26 }
( z9 u' \* i9 k2 X! V2 R% O R2 m. a* [27 return *this;
8 R0 g1 K& ], l+ B) C0 N28 }
2 Q* B! P+ R% |. P+ ^& {29 7 ?& v9 g: a! M8 A9 s5 p
30 void TEA::encrypt(const byte *in, byte *out) { % z, m& D3 }% l, l% f' v) C9 D: y
31 encrypt((const ulong*)in, (ulong*)out); ! A2 Z! t$ P$ g, K3 y: M9 a9 C9 G* U
32 }
6 R' y1 N% V8 ?; o% k33
1 y' E. Y$ q; h0 x5 T) N34 void TEA::decrypt(const byte *in, byte *out) { $ \, r/ ~' X1 t; u
35 decrypt((const ulong*)in, (ulong*)out);
4 e( l2 Y( B$ X& T- a9 I36 } 9 j8 P8 w! Y' @' _
37
' p! z1 D' |; ?) I; J! j9 l! I+ S38 void TEA::encrypt(const ulong *in, ulong *out) {
! |' m* ^. R4 i39 # y: n2 r: ~4 Y# U$ b
40 ulong *k = (ulong*)_key;
- N* E3 J, H* M1 J( Y41 register ulong y = ntoh(in[0]); 3 S" F/ }1 q+ d% O( W/ `1 X" E! e
42 register ulong z = ntoh(in[1]); 5 p+ u" F1 b% d
43 register ulong a = ntoh(k[0]);
$ r+ H" L7 u( J4 @+ K5 W" \44 register ulong b = ntoh(k[1]); }9 W. @ v" g0 `5 B* z R" {6 D* e
45 register ulong c = ntoh(k[2]); 1 L+ r: k" n) t2 i+ {
46 register ulong d = ntoh(k[3]); 5 I. a7 i2 r. p( V
47 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */ 9 M+ j! F% Q- c7 F; q7 N7 g
48 register int round = _round;
9 u, R) _# h4 b1 y9 z49 register ulong sum = 0;
8 M( i% Q3 H, a- K50 3 e: S$ x* s6 v7 O7 t6 T6 x
51 while (round--) { /* basic cycle start */
( q8 K9 v# t8 f& d) y52 sum += delta; 9 G7 p" b8 L4 e9 w! ~- z: ]
53 y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
6 A) x, L9 F' I/ {# F4 O54 z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
' X! C8 p R, N J4 ?+ d2 ]* b55 } /* end cycle */ , S* j/ k: e: d& N& ?+ j
56 out[0] = ntoh(y); 1 y0 W2 C' r' Y% `
57 out[1] = ntoh(z);
4 Z: ^# g1 M& b# k# `2 {58 } . H; e& C& \7 J( W$ _, o7 J
59
# m8 f' u6 A- ?) J0 l( d# x) z60 void TEA::decrypt(const ulong *in, ulong *out) { 6 H8 Y% w; l! |3 }# b/ G6 g
61
. M! M5 T3 D; f62 ulong *k = (ulong*)_key;
8 a, k9 w- }! T' o63 register ulong y = ntoh(in[0]);
% R( I$ U7 m1 H' J5 ~8 y/ h64 register ulong z = ntoh(in[1]); " }+ V4 E, D5 e" I2 Z% N7 b6 E
65 register ulong a = ntoh(k[0]); ; P" h' h, |8 P% W9 }# S/ l
66 register ulong b = ntoh(k[1]); " q) X* H1 {" v1 N
67 register ulong c = ntoh(k[2]); - J) v( R: c! d8 h: [( }
68 register ulong d = ntoh(k[3]); . g4 W/ R. A$ S* C" ~! g; c, Y
69 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */ L/ k' K0 ^0 C! G; h
70 register int round = _round; $ b. D0 J+ N" Y9 `8 L
71 register ulong sum = 0; 4 Z( {7 [! E, w+ ^$ J) K0 \
72 8 ?4 T; Z6 ^7 [7 L
73 if (round == 32) 1 d7 r1 K7 m. l+ J
74 sum = 0xC6EF3720; /* delta << 5*/
6 W# I% `" S- w/ t; u. B75 else if (round == 16)
3 }3 o. {& x6 v- R8 J4 _3 H76 sum = 0xE3779B90; /* delta << 4*/
& X$ E# d4 e' e5 J8 f77 else # a8 p+ [8 Y7 D! v' H
78 sum = delta << static_cast<int>(logbase(2, round)); 9 t5 X$ s; s Z4 w, D6 z, H
79 ' s8 `% J/ ?4 \6 Y$ s4 P8 \
80 while (round--) { /* basic cycle start */ ( \0 V6 Q* C- n/ D2 S9 L
81 z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
( b+ [$ q! e% P6 s/ t% f82 y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b); " t# y% _% }8 C& C4 C6 J1 B
83 sum -= delta;
1 {, V$ {3 b1 k9 R5 b6 i84 } /* end cycle */
" S3 ]% B; h& e$ p0 E85 out[0] = ntoh(y);
2 L: b& o- O& S( b3 K86 out[1] = ntoh(z); 8 N7 W) \9 G5 R# C3 d
87 }8 Z! c/ `# A# a' L$ k8 e
0 @3 U' E' n4 q# y6 v
需要说明的是TEA的构造函数: ' Y9 R, m# x( |- B; g
TEA(const byte *key, int round = 32, bool isNetByte = false); & _4 U$ m4 G V3 L ?6 a
1.key - 加密或解密用的128-bit(16byte)密钥。 ( y7 y! u# F; ]) W; I5 n. u
2.round - 加密或解密的轮数,常用的有64,32,16。 9 {+ }. R; }3 C& f
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 W: {. d% n
( X& J" D& C! Q0 L8 m" S最后当然少不了测试代码: |
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