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发表于 2010-1-19 19:59:57
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tea.cpp
1 #include "tea.h" , }5 n; q: ?) a5 S7 g
2 #include <cstring> //for memcpy,memset
) t. f! L5 N: e9 q) ] 3 Y! s% \9 e6 j8 {
4 using namespace std;
1 p' E* z$ A0 W, u/ u4 b3 r 5
8 D7 K, z, r, E# h 6 TEA::TEA(const byte *key, int round /*= 32*/, bool isNetByte /*= false*/)
+ e/ ^+ [3 N9 d8 r: Z 7 :_round(round) - z' e& i+ Z5 d- v
8 ,_isNetByte(isNetByte) { 8 u$ _( v L% L3 _
9 if (key != 0)
3 k9 D2 p5 |" I+ V) J10 memcpy(_key, key, 16); 3 z7 Y V$ t7 V1 u+ Y5 |, S: }) R
11 else 5 |$ G" U9 i+ { I: z( j
12 memset(_key, 0, 16); 4 m. H0 B8 }& u. M- N8 j
13 } ; c F. f3 n% H% ]; }; w
14 $ G* @ Y, Z7 l* J5 J: f7 p
15 TEA::TEA(const TEA &rhs) f) u/ [9 b; u- d8 m. V) y
16 :_round(rhs._round)
! ^: _5 k2 U( N3 Y17 ,_isNetByte(rhs._isNetByte) { ) Z' c& U) U5 ^: R
18 memcpy(_key, rhs._key, 16); 4 _* y6 d/ g1 B- b" T% ^8 s' s
19 } 3 {* ]( `9 O& l' L
20
( T9 g% w5 i! S1 B21 TEA& TEA::operator=(const TEA &rhs) {
$ q# }( l }* X/ s f22 if (&rhs != this) {
: m4 ]9 q6 e0 o" h) h23 _round = rhs._round;
6 w! l3 z$ c! M4 H& X5 X: ?24 _isNetByte = rhs._isNetByte;
4 {) \6 A' j8 J( Q' K/ o% h3 D25 memcpy(_key, rhs._key, 16); 1 i1 s z0 i2 p
26 }
' x0 }9 b" v2 `% I27 return *this; ( Y- O0 c# z& ?1 i
28 }
2 m( G, t+ k; N; ]0 T29
3 Y3 e9 q; x4 z( F% C30 void TEA::encrypt(const byte *in, byte *out) {
% q$ L5 J$ E8 b& e1 a- H8 k31 encrypt((const ulong*)in, (ulong*)out); ( n) S# o' G! t2 |- a2 \- {' |; @
32 }
# c5 x1 }3 c! ^33
9 A* B% q1 }: c: Y" a9 Q$ w" N34 void TEA::decrypt(const byte *in, byte *out) { . l: U$ M2 X: |( D8 u( e
35 decrypt((const ulong*)in, (ulong*)out);
$ ]. w) H' z- Q- T; c6 m36 } ! h* m1 S3 ~; E4 E& X! c9 _: `
37
$ y1 H% n. `% Q* a38 void TEA::encrypt(const ulong *in, ulong *out) {
8 P! [* o6 F1 W, Z9 I39
}+ {3 m, ?$ E3 g40 ulong *k = (ulong*)_key;
# l; m9 K. E1 i, @5 r' N }41 register ulong y = ntoh(in[0]); + M h/ p- K9 i) G6 g6 e8 c) Z2 v/ X
42 register ulong z = ntoh(in[1]);
3 [+ k* F$ f- g3 T, Y7 V8 f43 register ulong a = ntoh(k[0]);
1 @4 s& W3 ?: ]0 d F) G44 register ulong b = ntoh(k[1]);
$ u; s% K! w$ y. \45 register ulong c = ntoh(k[2]); ( K% E( h+ @) e7 Q# I
46 register ulong d = ntoh(k[3]); 5 V$ g" D3 }/ U/ R* {0 S; U
47 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */ ! p6 g9 V- Z8 p- f! `6 G: w
48 register int round = _round; 5 `9 q$ |1 k0 W6 z
49 register ulong sum = 0;
1 V$ N S4 x3 u2 B# Z50 6 ~, I+ I( v5 `
51 while (round--) { /* basic cycle start */
. b7 Z) Z6 `( v) | ?52 sum += delta; ) s' E- r, |6 B U
53 y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b); * ] `% T. P8 p, I3 l
54 z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
1 ~. y- b" T2 i55 } /* end cycle */ 2 Y3 s8 Z6 D' t; R4 z
56 out[0] = ntoh(y); 9 y; s. G+ g' ~& Q+ h; ~8 i" G
57 out[1] = ntoh(z); , d: I! ?+ R' v& f7 ^3 {
58 }
% z N- s' e7 [ K59 0 P3 U/ F# q5 r& b+ x% V, c
60 void TEA::decrypt(const ulong *in, ulong *out) { 5 w, c1 J K/ p- i& o, ?4 Z
61 6 I9 ?' a6 _0 ~% e/ j8 g
62 ulong *k = (ulong*)_key;
9 |1 c3 B: i: D1 I) j3 W8 G9 {63 register ulong y = ntoh(in[0]); 3 i2 z# M4 Z$ a8 ^3 ~
64 register ulong z = ntoh(in[1]); ) W2 @1 I2 H) B& j0 I1 H
65 register ulong a = ntoh(k[0]); 6 a \& z+ B1 ~# P# x
66 register ulong b = ntoh(k[1]);
# Q6 ]& [ l/ e- [& r67 register ulong c = ntoh(k[2]); B3 c! z+ X/ b: [9 d/ y3 ~
68 register ulong d = ntoh(k[3]); " {4 v* p- S& g
69 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
8 j d2 _; X- b70 register int round = _round;
! B# K. H+ v, d/ B71 register ulong sum = 0;
% [; h$ I* R" ^72
! w: v1 v' q5 X' _1 O73 if (round == 32)
1 q$ e3 ?5 J' h74 sum = 0xC6EF3720; /* delta << 5*/
?6 F. H, v# B) x$ c75 else if (round == 16) / A( W0 U! h: X) H( o- ?6 R
76 sum = 0xE3779B90; /* delta << 4*/ , f4 K$ B1 W h d& @, y
77 else 8 m* K: H0 G2 Z8 ]/ W$ q" `
78 sum = delta << static_cast<int>(logbase(2, round)); 7 x, N8 a& y1 A7 E7 x
79 & p, q8 ^/ N: Q5 b, a2 K
80 while (round--) { /* basic cycle start */ / `% L) T- F/ U; W! L. L
81 z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); & a, B! s9 M2 {, K ]
82 y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b); ) ]3 m V: M4 K* v+ e3 ^) E
83 sum -= delta;
9 ?5 D, Z: z' S84 } /* end cycle */
% G1 m @+ W; k85 out[0] = ntoh(y);
$ P! f+ R4 t( B6 d5 j0 h7 [8 ^86 out[1] = ntoh(z);
2 ^6 G9 U8 l" B6 ~$ V, b6 H87 }
) Z; F( s5 o5 d9 x+ v$ [
0 o( q7 w3 O# M7 ~需要说明的是TEA的构造函数: ' z1 N3 D5 F; P) y
TEA(const byte *key, int round = 32, bool isNetByte = false); ( U. V. B; D# X" o
1.key - 加密或解密用的128-bit(16byte)密钥。
7 l+ z2 |: e5 {9 p2.round - 加密或解密的轮数,常用的有64,32,16。 , [8 C: [ Q' 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! 5 s; ^5 E9 a# t1 u+ Q" H
/ I8 S9 R+ }+ w z, m$ x最后当然少不了测试代码: |
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