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发表于 2010-1-19 19:59:57
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tea.cpp
1 #include "tea.h" ' ~; N- K6 c# i# g+ R
2 #include <cstring> //for memcpy,memset
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7 R$ Z; X) @0 u X 4 using namespace std;
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6 TEA::TEA(const byte *key, int round /*= 32*/, bool isNetByte /*= false*/) * K1 ~, I" u: r6 j
7 :_round(round) . X0 U4 B, _$ F
8 ,_isNetByte(isNetByte) {
7 l, D( B- z; @ 9 if (key != 0) $ D- C3 O) N. @/ N! O+ u. O
10 memcpy(_key, key, 16);
* E% r, X% {: f* m+ S0 }11 else
7 r1 s# a, w- c& X( R6 U- [12 memset(_key, 0, 16); ) l% Z' ]0 W5 R! S" T
13 }
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15 TEA::TEA(const TEA &rhs) 9 V. ?; H8 j6 w- H5 K
16 :_round(rhs._round) + Z$ ]7 O! _% f8 ?# b9 T
17 ,_isNetByte(rhs._isNetByte) {
4 u6 X2 N6 Q- b+ \4 d/ [ G18 memcpy(_key, rhs._key, 16);
+ {6 a( [. y. b: h, a+ o* I/ \% Q19 }
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21 TEA& TEA::operator=(const TEA &rhs) { : q+ }6 a# C' W/ R9 a: W" v: F
22 if (&rhs != this) { % L- F9 ~ @& k; i
23 _round = rhs._round;
9 s, v0 E8 w6 |# W2 ?8 r( p: R. }24 _isNetByte = rhs._isNetByte;
; n. g- r- [ s4 X% h& z5 H25 memcpy(_key, rhs._key, 16); & P+ b3 u6 A: B0 l$ \. a$ ^4 ?
26 }
3 c# I* E( r) y+ H7 s" @. B27 return *this;
/ @) p! ?1 g/ ?28 }
, f3 S: ]7 v Y9 p: ]29
2 X& S5 g( j2 E+ q/ ^30 void TEA::encrypt(const byte *in, byte *out) {
. |! y0 _) @5 ?% y5 \2 C+ R5 r7 Y: l& V31 encrypt((const ulong*)in, (ulong*)out); " _9 p# e% l W9 Q1 E1 Q7 T$ w
32 }
, b% H5 W! `6 z. a/ g* I7 W0 N9 U0 v33 * B4 d8 ]( e( ~& r
34 void TEA::decrypt(const byte *in, byte *out) {
8 }! `$ V2 S5 Z* G35 decrypt((const ulong*)in, (ulong*)out); ; \3 F7 V3 [0 v6 y9 q8 U o& L7 x4 j a
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38 void TEA::encrypt(const ulong *in, ulong *out) {
" }7 Q4 K$ `$ ^2 y& S0 F39 : {7 B( ]- U; u& C$ ?
40 ulong *k = (ulong*)_key;
/ g. ?8 _( ^. v! s( U7 i41 register ulong y = ntoh(in[0]); : h' r+ N4 V2 L$ c. ` ^' p
42 register ulong z = ntoh(in[1]);
4 j" [3 r' R* p5 p% q43 register ulong a = ntoh(k[0]);
# U; S4 y- d1 \# `- r1 N( m9 E44 register ulong b = ntoh(k[1]);
$ r; Z! g) U0 B2 x. D6 h/ x45 register ulong c = ntoh(k[2]);
- e3 x( ]/ R0 H" u- `' e" }46 register ulong d = ntoh(k[3]); ' G+ T3 \5 o; S* i3 H" z
47 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
4 a5 C5 A; y& a+ C; z. s1 z48 register int round = _round; , e+ j) Y. j3 ] z- T3 Z' e$ |( D# ^
49 register ulong sum = 0;
+ Y9 M) m: F( O: j$ i" A3 V50 5 v/ z% n5 O: y( h- H
51 while (round--) { /* basic cycle start */
. F0 r; H( E/ q* ^52 sum += delta; 3 j% I, T+ b. D( d3 E7 m* c
53 y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
$ J2 k. l" H5 \2 Y1 I54 z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
; }+ F: V% i# f ~0 r! ]! R$ t55 } /* end cycle */
! W2 i$ X6 x. x8 I* v, x" n56 out[0] = ntoh(y);
; o% |2 B; Y# S- l57 out[1] = ntoh(z); 1 U- B2 ], d7 l: D2 { x* b2 ]) j0 S& Z
58 }
3 A" p8 R7 \) n7 y- p59 * i& \) z& I! h+ O, c. n9 n9 V
60 void TEA::decrypt(const ulong *in, ulong *out) {
3 g6 T$ j: j) D) K61 2 _/ t$ I4 I: q5 D# _0 J% Q
62 ulong *k = (ulong*)_key; 1 J- s! N' w( a2 b
63 register ulong y = ntoh(in[0]);
" Y1 _, [( p7 y s, ~64 register ulong z = ntoh(in[1]); $ R2 T+ N! l" v, v
65 register ulong a = ntoh(k[0]);
1 q# _+ T7 p8 S. y! H66 register ulong b = ntoh(k[1]); + X% ]( m$ F5 s7 @! Z1 b6 L( l
67 register ulong c = ntoh(k[2]);
' d' D X2 i4 Y7 [* O; r+ f5 K68 register ulong d = ntoh(k[3]); : `& r) e3 K3 A; l" v
69 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */ $ n1 Y$ {" D% J
70 register int round = _round; ' R2 U1 a# _. Q6 b. j3 _
71 register ulong sum = 0; ) h" ^8 S/ z4 Z* K
72
. N3 ^$ W+ W7 x: K9 I73 if (round == 32)
7 K: `- _+ i3 L3 v3 e; D74 sum = 0xC6EF3720; /* delta << 5*/
1 [0 ] w* B( q" Z. \. P; ~75 else if (round == 16)
) Z/ X8 W0 \6 g; i1 g76 sum = 0xE3779B90; /* delta << 4*/ 6 l' k3 v9 [2 v( ~6 W
77 else C" R" R) o ^
78 sum = delta << static_cast<int>(logbase(2, round)); ! }, X" \. j; y
79
8 q2 q8 [0 }3 d9 P7 o80 while (round--) { /* basic cycle start */
3 @2 O* y- t2 E3 v, d) W7 X. i' u81 z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); 7 g4 {, Z) r- E$ y
82 y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
8 S+ [2 B/ J7 q) W+ v83 sum -= delta;
" G/ D/ U/ V- d7 p0 g84 } /* end cycle */
- _5 P- t/ }* q3 `& @85 out[0] = ntoh(y); # }4 K4 {- N+ J/ w" \' }1 y
86 out[1] = ntoh(z);
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需要说明的是TEA的构造函数: * e$ w$ `% m0 p$ Y, m
TEA(const byte *key, int round = 32, bool isNetByte = false); 4 F, b7 J+ U) h$ ?
1.key - 加密或解密用的128-bit(16byte)密钥。 # Z5 r# s2 I0 s( p0 r- q
2.round - 加密或解密的轮数,常用的有64,32,16。 ; Y/ Y! Q# j" `3 \
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! # X! Q- w2 m, w" F) G
9 }. P$ \; W, H9 J3 u( ~4 ^最后当然少不了测试代码: |
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