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发表于 2010-1-19 19:59:57
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tea.cpp
1 #include "tea.h" * ?+ o/ ^5 M+ ]' M. A
2 #include <cstring> //for memcpy,memset
5 `! P5 S V7 h( g 3 6 q4 v5 c) y L- H5 h
4 using namespace std; ; _3 Y0 o1 _% C* P: ?' V
5
7 I6 Y+ C g: Z1 i 6 TEA::TEA(const byte *key, int round /*= 32*/, bool isNetByte /*= false*/) " [, n) @; S' G1 ?% L
7 :_round(round) 1 M" f. K @* _( z
8 ,_isNetByte(isNetByte) { 3 d2 R: x# a5 G
9 if (key != 0) : R% z0 n: V S% y7 ]% m7 `
10 memcpy(_key, key, 16);
C- @6 ?) G4 [9 e! E4 q11 else $ g" i# J; M/ v/ l
12 memset(_key, 0, 16); 5 W) I5 @, S. _' Y4 Z; B
13 } ; j) s) {* W/ c$ [
14 , X- z5 B& t0 |( l0 X* ^8 _/ Q
15 TEA::TEA(const TEA &rhs)
, o; W. e' F0 w5 Z' {8 ^0 X7 q16 :_round(rhs._round)
1 F) p2 A! d3 C17 ,_isNetByte(rhs._isNetByte) {
% B" `3 I9 T8 _! N- I6 r18 memcpy(_key, rhs._key, 16); . b- x( P1 y) z: w
19 }
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21 TEA& TEA::operator=(const TEA &rhs) { ! v* S/ P8 f" K% k* k
22 if (&rhs != this) {
2 S0 E0 d; H. g% a4 W. f: N23 _round = rhs._round;
$ J' ^. x$ C. L7 X" h24 _isNetByte = rhs._isNetByte; 7 q. c8 P' k6 U" C9 E8 l2 Q5 {
25 memcpy(_key, rhs._key, 16); 0 h$ y& Y" Y. F; C$ _# r
26 } * i5 V; O& X5 I9 Q" [1 m) Y
27 return *this;
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29 " s9 o- f7 f4 b: Q# n% L) l
30 void TEA::encrypt(const byte *in, byte *out) {
4 U5 e4 @0 x E- R$ G8 p5 Q31 encrypt((const ulong*)in, (ulong*)out);
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33 ' |: ?* R4 d- O. r7 o9 Y3 S, n
34 void TEA::decrypt(const byte *in, byte *out) { : @1 N& x+ F' x- ? Q+ ~: H Z
35 decrypt((const ulong*)in, (ulong*)out); 2 r; R) P! @& w" l! ]
36 }
{# f% g: s) A& @* J37
4 Z2 C6 S( p) R/ p" D38 void TEA::encrypt(const ulong *in, ulong *out) {
$ G% [" y( @' ?5 O39 ) i' h4 d5 r. f k
40 ulong *k = (ulong*)_key; / k/ K }9 v, v _. B- \ v
41 register ulong y = ntoh(in[0]);
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43 register ulong a = ntoh(k[0]); : ^# ~: D0 O- t* V4 u, Z
44 register ulong b = ntoh(k[1]); . u7 V( E: j, [6 K- _, w
45 register ulong c = ntoh(k[2]);
( a/ Y4 Y& J9 y46 register ulong d = ntoh(k[3]);
6 s8 X4 B, y n' a47 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
6 q' X9 J# ?" X7 `8 K48 register int round = _round;
- \5 i# u8 g% ]) G+ _49 register ulong sum = 0;
) L0 c7 ^/ S% f50
% `/ V) S: I7 H, z) P W# m51 while (round--) { /* basic cycle start */ 6 \0 a& @& N, ^; n8 S; U
52 sum += delta; ( @, C9 v+ H8 r4 R
53 y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
% g; x; T- j+ ?% h/ n5 O54 z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); & Z+ @6 b. r2 t0 A" e: w
55 } /* end cycle */ 6 H( }" P4 ]6 g _5 v2 f
56 out[0] = ntoh(y); ; Z$ B8 F" G5 h+ k1 f5 _
57 out[1] = ntoh(z);
5 @+ K: \$ _! ~5 V58 }
) X! d% Z3 \$ \4 a9 i59
1 g( T3 |# L4 Z# ^" u( O1 r5 m1 J/ A60 void TEA::decrypt(const ulong *in, ulong *out) { & W; X" D* W& R& F# C1 D8 e
61
) d, ~+ ~/ `; ?3 h, h- j62 ulong *k = (ulong*)_key; M" f8 E' f! q7 z% F' C$ D4 u
63 register ulong y = ntoh(in[0]); . j5 d s. B8 _( r; o K" ]$ q) L
64 register ulong z = ntoh(in[1]); 8 V l! s- m/ A) `. L
65 register ulong a = ntoh(k[0]); - G9 T& Y$ K, h( f
66 register ulong b = ntoh(k[1]);
" W( r" L/ U* G# f/ n' e67 register ulong c = ntoh(k[2]); & R$ q4 C1 n$ ^
68 register ulong d = ntoh(k[3]); 8 R2 ]; E; _: ~- u3 ]$ W
69 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
/ S$ Y+ W8 U- p0 r70 register int round = _round; % F6 E) N9 C2 @1 }
71 register ulong sum = 0; 2 Y5 a3 S4 i. c% d+ V; O2 D* J
72
: _( X+ Z5 w6 l0 m+ d' f73 if (round == 32) , h, S0 j: f, y; w; s$ ?$ w
74 sum = 0xC6EF3720; /* delta << 5*/ 6 w% e: {0 s/ V. ?$ Z
75 else if (round == 16)
& V2 ?7 V4 [) U7 d+ _/ ]; d76 sum = 0xE3779B90; /* delta << 4*/
- d/ _9 q( K" m+ Z77 else + V! }: Z& V0 U- d. @
78 sum = delta << static_cast<int>(logbase(2, round)); 2 A. _; O# f( s/ B
79
; C0 L' `, l, x& }6 o a! ?80 while (round--) { /* basic cycle start */
7 |6 Q' X+ t$ H, k. M6 j81 z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
3 d5 s3 P0 G/ B7 ?4 X, V82 y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
2 l" a8 z+ {$ t4 ~; f83 sum -= delta;
/ O9 y" k" }7 [8 y- ?% ?84 } /* end cycle */
- m: J$ @) a2 b1 @5 G85 out[0] = ntoh(y); / n6 w/ P- C. ~1 ~- q' G7 W: \0 d a
86 out[1] = ntoh(z);
8 ?1 |# s- C, q87 }
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需要说明的是TEA的构造函数:
% C" q) @8 d/ U$ z' NTEA(const byte *key, int round = 32, bool isNetByte = false); + r. z; `! } e# D. n
1.key - 加密或解密用的128-bit(16byte)密钥。 ; K! [8 T/ a$ \: R( b- J2 `
2.round - 加密或解密的轮数,常用的有64,32,16。 2 @$ T, h" P# x* v1 G G4 _( N3 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! ( u: p$ K( B7 f
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最后当然少不了测试代码: |
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