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发表于 2010-1-19 19:59:57
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tea.cpp
1 #include "tea.h" # _! U0 U9 D$ e4 F% X! N
2 #include <cstring> //for memcpy,memset 7 T( N2 N9 C+ Q. |. c" z
3
: c1 C1 l8 M9 Q# v& ]& [8 A7 {: m+ A! |) h% _ 4 using namespace std; 5 }( b6 W3 }8 E5 Y4 V' t# ]
5 , x5 \' C6 B4 Y
6 TEA::TEA(const byte *key, int round /*= 32*/, bool isNetByte /*= false*/) , h/ C5 ^) v/ E! f
7 :_round(round) ' Z4 r# t' Q& ^& Y7 F
8 ,_isNetByte(isNetByte) {
' o0 [8 l1 P; T7 D1 d 9 if (key != 0) 2 @6 X) Y" K( c+ l0 u& ^" Z/ ?) h
10 memcpy(_key, key, 16);
) X6 F* U. A% e0 Y11 else ; t8 w; l1 @* \- r8 |
12 memset(_key, 0, 16);
3 {2 _; C8 f( s+ k5 ?13 }
/ [# t- A$ L: k+ r4 S14
3 o' b" X# L- H9 v t15 TEA::TEA(const TEA &rhs) ( A( x; E6 P: S' }3 T
16 :_round(rhs._round)
1 Q; j* R+ H5 M' K1 w% h17 ,_isNetByte(rhs._isNetByte) { 8 C) g1 D" @- r/ {, q9 l$ X
18 memcpy(_key, rhs._key, 16);
3 \4 d* T: d1 @. m/ p5 W8 J" Y19 } : P9 U, ^, z& c8 r$ |2 M
20 4 a" x, R+ m( P0 D- Q% N, S
21 TEA& TEA::operator=(const TEA &rhs) {
; B5 u4 J. y3 l; q; e' X% y' H* d22 if (&rhs != this) { g) a O) h2 p* V, y
23 _round = rhs._round; 7 d5 E1 C% s, \
24 _isNetByte = rhs._isNetByte;
w( L: ^$ a; `. n0 s25 memcpy(_key, rhs._key, 16);
- c, ]$ V5 f U, [- C26 }
+ H3 ]' j( t9 ^27 return *this;
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29
1 | I& w+ Z/ ]" |+ x0 Q30 void TEA::encrypt(const byte *in, byte *out) {
* Z# c* Q( V2 a! H31 encrypt((const ulong*)in, (ulong*)out); 4 |2 I0 P0 \$ x- @9 w, r2 ~1 E
32 }
$ G2 L% A1 r/ Q+ P/ _33 1 Z( V9 u6 R# D1 W9 _6 `
34 void TEA::decrypt(const byte *in, byte *out) {
! v2 r5 U, `' M35 decrypt((const ulong*)in, (ulong*)out); 3 O0 A: s# @ N6 Y* B
36 }
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38 void TEA::encrypt(const ulong *in, ulong *out) {
/ ~* @. H; w4 O4 |5 L) I# e% M39
P" p8 q! x+ j6 B$ J/ |7 A4 ?40 ulong *k = (ulong*)_key; ' Z! s% E: l4 M
41 register ulong y = ntoh(in[0]);
4 b" T0 [0 t8 r2 q: p- j3 m# u& R0 h42 register ulong z = ntoh(in[1]); 6 z; F2 p4 ]; Q" u6 J. n$ y
43 register ulong a = ntoh(k[0]); ' ] j7 Y, d# A) h* Y5 _4 Q
44 register ulong b = ntoh(k[1]); : K$ L, n2 U: z t8 O0 X
45 register ulong c = ntoh(k[2]);
! o1 R" L# y3 x46 register ulong d = ntoh(k[3]); 2 s! D0 w9 D8 `
47 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
' |; b; |2 m: |: r) P. O48 register int round = _round; 5 D9 B! N5 p1 o+ D9 K2 s; P
49 register ulong sum = 0; ( m I" y# y* ]" _4 L. n
50 3 e1 z- t: U4 Q- i7 G1 U
51 while (round--) { /* basic cycle start */
0 H7 x! c+ q* W$ V7 u. U52 sum += delta;
# M4 \4 |) R; T9 }. a53 y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b); - q6 H/ v6 ]) n" ?5 {
54 z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); 2 y, U+ Z; q. z7 |
55 } /* end cycle */
' {1 _9 P7 X8 }+ Y& a5 W56 out[0] = ntoh(y);
( v0 Q; q; I5 o( T/ {+ M0 w8 l57 out[1] = ntoh(z);
! c8 G" V Q# O" Q F3 n58 } 1 l1 w' h; {( G K/ J& {. K: ^+ H- g
59
2 ^6 O- q- Q$ w# A: y# B; R; |60 void TEA::decrypt(const ulong *in, ulong *out) { 2 C: n6 H, ^* N5 ^' S
61 . U* X* e2 o1 C6 X. N2 G* {- a( c
62 ulong *k = (ulong*)_key;
* |+ |3 O3 G0 s7 S( h* @7 ~63 register ulong y = ntoh(in[0]);
* K7 R5 N: e [ }; I6 G7 T64 register ulong z = ntoh(in[1]);
6 e" F" S- M1 d9 X9 Q65 register ulong a = ntoh(k[0]);
# J8 c8 L. h; H" D0 _1 b66 register ulong b = ntoh(k[1]); $ `/ a" ~# u B9 [4 V1 o
67 register ulong c = ntoh(k[2]); : _' m( H% I% j6 H% t% x
68 register ulong d = ntoh(k[3]);
$ R3 ^" \& v+ s8 @& |! L. G3 X4 U69 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
: Q; m" Q# s2 a/ A70 register int round = _round; 6 L8 D2 \# n2 ~
71 register ulong sum = 0;
6 A6 B- s# \' a% s) F72 $ ~- E" m. c& [$ ^& A/ T
73 if (round == 32)
' N1 h+ `; t7 W7 y- [74 sum = 0xC6EF3720; /* delta << 5*/
& J9 Y* g; p, s* M75 else if (round == 16)
0 r" F9 Q5 U5 |5 h |: k% d" L76 sum = 0xE3779B90; /* delta << 4*/
2 t0 l( [' J/ @9 @5 }/ d77 else
0 z3 q' g( u1 v C! O% a78 sum = delta << static_cast<int>(logbase(2, round)); 1 P' w, j, k# q7 y! b( \+ t0 z! {
79 ' q6 G" ^4 i# t$ m+ Q
80 while (round--) { /* basic cycle start */ : \& e5 d: } R7 ~3 p* g% ?
81 z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); 7 ~+ `3 c! w+ K7 l; o3 b8 H$ [
82 y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b); / @) t D7 T8 i# t1 N; l- }$ x7 ]
83 sum -= delta; # h# Y% r$ g D/ Y7 i
84 } /* end cycle */
$ W# }) h4 R8 Y! ~- Y85 out[0] = ntoh(y); ; w- b) l7 j# `, l B! ~
86 out[1] = ntoh(z); 3 j# T' L% ?( ^" F* j; o
87 }: S6 z% x0 C* o( n0 X6 p/ o
7 @9 c$ Q3 w( f需要说明的是TEA的构造函数:
. P8 y5 `* V9 \5 OTEA(const byte *key, int round = 32, bool isNetByte = false);
1 t9 |( _6 U3 ]" j1.key - 加密或解密用的128-bit(16byte)密钥。 * D9 C: X, E* v; ~' b' o: h+ D( ^, H
2.round - 加密或解密的轮数,常用的有64,32,16。
1 _: |* }2 P0 _5 G8 l) S( j. F3.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!
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4 L$ G' q# g& C M! @/ j最后当然少不了测试代码: |
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