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发表于 2010-1-19 19:59:57
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tea.cpp
1 #include "tea.h" ; B' e% O$ d/ k
2 #include <cstring> //for memcpy,memset
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/ G1 x. k7 y3 }1 t& y. } 4 using namespace std; ' ~& M" X r/ r1 a. m3 G+ D8 T
5
4 w4 @6 `/ \! l @- R- m 6 TEA::TEA(const byte *key, int round /*= 32*/, bool isNetByte /*= false*/)
9 c. ?: `5 R9 j# E 7 :_round(round) ; m- G0 T" p5 M5 z. R$ k
8 ,_isNetByte(isNetByte) {
* F! U4 _ v0 i 9 if (key != 0) " O3 U' E$ L" t: |/ n7 U" }
10 memcpy(_key, key, 16); 9 a7 W0 e6 c; F% {
11 else 7 B4 `8 I1 F" V9 M. X1 K! v
12 memset(_key, 0, 16); ' R) X; S0 _, B9 l; ^
13 } 8 S2 N3 F0 U+ K/ H
14
# ^" e, `8 Q# X8 {8 Z0 {' T9 O15 TEA::TEA(const TEA &rhs) & |7 i/ X& U7 P0 E+ B
16 :_round(rhs._round)
3 x' }8 q% r# }6 d0 V17 ,_isNetByte(rhs._isNetByte) {
) U/ Q6 Z" J: b) o# J) l18 memcpy(_key, rhs._key, 16); % C7 U" k u& O
19 }
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21 TEA& TEA::operator=(const TEA &rhs) {
" h* s+ ?/ B5 K/ s) \6 j6 ~' t22 if (&rhs != this) {
I0 n( M6 _' s$ d+ ?23 _round = rhs._round;
5 D0 r. [- I ~- X+ A24 _isNetByte = rhs._isNetByte; 3 q4 h: R. f( m7 v: s
25 memcpy(_key, rhs._key, 16);
0 ~ t j- @2 {( `26 }
9 H4 V- p; a7 Z: c27 return *this; 5 n- L5 E7 V+ i( ^
28 }
3 U4 s( V8 a! m9 d4 B' y29 5 G5 |" l/ B# M1 R: J# U
30 void TEA::encrypt(const byte *in, byte *out) {
# }0 {3 j0 f. `* l6 | r/ O+ C/ ^# g31 encrypt((const ulong*)in, (ulong*)out); , @! |5 s! Z! U1 F# U! ^
32 }
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( f# i0 w( k! }+ |# @34 void TEA::decrypt(const byte *in, byte *out) {
9 a; p8 ~" m' F. F' A. m6 v1 S35 decrypt((const ulong*)in, (ulong*)out);
% m2 |; H- e, @, j3 }36 }
2 }" V. E# G! n. N37
: d2 p( f( m( u4 E" E" ]5 R i38 void TEA::encrypt(const ulong *in, ulong *out) { + `$ n8 O" {7 ]" Z1 Z. D
39 + |4 d) V, P# Q1 t2 f
40 ulong *k = (ulong*)_key;
9 Z3 S$ a- X8 J0 v) f41 register ulong y = ntoh(in[0]); & t* V2 c l8 b1 m3 ~% z( c7 z
42 register ulong z = ntoh(in[1]); * G% f# C' ^2 y1 S, h9 [( {( p% J
43 register ulong a = ntoh(k[0]);
2 j: L) l9 t! G9 x' f' m0 y5 S6 m44 register ulong b = ntoh(k[1]); 5 l% y/ N$ W2 g3 M
45 register ulong c = ntoh(k[2]);
Y' ?3 U% H5 Z- H/ u3 I46 register ulong d = ntoh(k[3]);
7 [( |/ S# c5 u47 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
, ~' D* Z: _# K) I ]) l+ N48 register int round = _round;
4 {: I0 X6 v" h0 s5 L0 r49 register ulong sum = 0;
- y% K& L% U: F+ A) V50 1 e0 q, o+ C) T y7 ~* I
51 while (round--) { /* basic cycle start */ ) E% x# k2 C) s4 t: [9 h
52 sum += delta; / Z% ?- t* b: d( Y
53 y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
/ ]7 L* z# S; }: x& D54 z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
3 s6 R4 o/ V% {9 F55 } /* end cycle */
8 Q4 s7 ?0 V; {) [8 n56 out[0] = ntoh(y); 0 E1 A9 S/ ?, C1 t: j
57 out[1] = ntoh(z); # `0 O ?; k- S) q) [
58 } 0 H! \- X5 [ X5 d. x. }; ~, ]- `
59 1 u0 e* @8 s" N# a c2 f8 _- i; j& V
60 void TEA::decrypt(const ulong *in, ulong *out) { # ~' h4 E9 e8 p$ L6 C6 F
61
: h4 y/ \9 G) e# Q8 g2 S62 ulong *k = (ulong*)_key;
8 Z: w% D6 ?) i- P" e) `63 register ulong y = ntoh(in[0]); 4 f& Q: j* s6 c( B( s" ^6 U' y
64 register ulong z = ntoh(in[1]); 9 z4 c4 L# D/ U7 }" }8 C1 X
65 register ulong a = ntoh(k[0]); 6 A7 s3 f3 Q( m. P6 _
66 register ulong b = ntoh(k[1]); . k. ~8 z+ T+ ~: C, U: t' {
67 register ulong c = ntoh(k[2]);
) b6 H; k# k1 Z5 k8 I7 ~68 register ulong d = ntoh(k[3]); ; k* v) h4 Y ^& X! u
69 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */ * j, i/ |" v( U8 j- B1 h' i. J# A
70 register int round = _round; $ f" H! J! _6 g- O5 l9 ]8 V7 l) Y
71 register ulong sum = 0; 0 q1 F6 i& v9 @) W
72 ' o; P& t0 Z; C; N7 S- @9 o/ }
73 if (round == 32) 8 P4 C9 B; ^/ q: Y: I, E
74 sum = 0xC6EF3720; /* delta << 5*/
% T+ Z4 H$ R/ e) e& s& R2 y75 else if (round == 16) 6 j8 v7 B- h4 ]- P% N1 v
76 sum = 0xE3779B90; /* delta << 4*/
5 w* a& ^/ P# u; d4 x1 m6 @3 d77 else . h6 J4 _7 [) i% H
78 sum = delta << static_cast<int>(logbase(2, round));
w6 h, m; _/ O5 ~) D* }79
$ [) @5 M8 `7 J80 while (round--) { /* basic cycle start */ - }- R* D! f( L l9 |' i( Y
81 z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
% R2 I' j9 u f3 T; I0 m82 y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
" F, _7 E* ~) k5 ?7 m83 sum -= delta;
1 x( `" I1 x- g& i. U84 } /* end cycle */
j) M" A% U. P l7 g3 k" w/ D: r( z/ l85 out[0] = ntoh(y); * D3 f3 y& A# M: K
86 out[1] = ntoh(z);
! `, v- [5 N! O1 l; N7 s87 }
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: Y4 _% T' E) Q需要说明的是TEA的构造函数:
4 j2 C$ _( y. {4 ~5 U NTEA(const byte *key, int round = 32, bool isNetByte = false); 6 ~, F1 I' Y, E5 I2 J/ Y- K0 `; V
1.key - 加密或解密用的128-bit(16byte)密钥。
& y! W3 A* T/ _' x2.round - 加密或解密的轮数,常用的有64,32,16。
6 I6 Q1 ~3 q" l- b3.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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- Y! W0 F( T$ Y) W7 N& U" N最后当然少不了测试代码: |
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