|
|
发表于 2010-1-19 19:59:57
|
显示全部楼层
tea.cpp
1 #include "tea.h" + k u5 F1 d3 G, H: V; Q& f
2 #include <cstring> //for memcpy,memset " f; R) A3 x8 m6 ?
3
% ^5 z8 f+ y7 `; ~* f# e1 ]& t3 C$ _ 4 using namespace std;
+ [3 K- d# ~, X! ^7 g4 O" c 5 y( h* i# H( n9 ?3 y$ \) C2 r; N
6 TEA::TEA(const byte *key, int round /*= 32*/, bool isNetByte /*= false*/)
: h" Y% w, r& s% g- ] 7 :_round(round) : s K9 R+ A/ s4 `2 m
8 ,_isNetByte(isNetByte) { , S. o9 {5 j5 E% L7 ]$ \
9 if (key != 0) 1 y M! E- A2 @% I# g G; v
10 memcpy(_key, key, 16); . W: g9 \; U" ]( P% i, `2 M# ~. h
11 else % g7 ^3 m) s0 C e, c8 G6 k9 S" R
12 memset(_key, 0, 16);
m8 I0 e( A0 p( t8 j- W e13 } # x( y7 h k+ b' j1 o
14 $ z/ h; t/ E4 \5 N) y! r* H- N V
15 TEA::TEA(const TEA &rhs)
3 f% J8 w u" a16 :_round(rhs._round) / Q: M+ h4 a, L% p5 T/ i
17 ,_isNetByte(rhs._isNetByte) {
% H. t5 k1 C8 l: C# a, Z18 memcpy(_key, rhs._key, 16);
' {- p% Z V7 G$ z19 }
J f' s# j8 [' e( n20 , s2 Z5 x, M6 u; y& N2 @
21 TEA& TEA::operator=(const TEA &rhs) {
; N S7 S: [7 v; O22 if (&rhs != this) { * W) L- p8 G+ n6 ~ ]: V" b; R
23 _round = rhs._round;
5 Q9 e* R$ k8 e. I6 p: A24 _isNetByte = rhs._isNetByte;
$ t( ^% b7 f7 f& {2 p/ E25 memcpy(_key, rhs._key, 16);
# v4 S+ H7 [# h$ X. r26 } + i1 g8 ~) o- J2 }2 n' E
27 return *this;
0 R% q6 p" j% J# E( e1 U28 }
' i! v+ }& V! |1 D; U; b* v, Z29 $ a; l p8 k7 s2 N& s9 g( [/ @- m
30 void TEA::encrypt(const byte *in, byte *out) { ( E5 H: W/ V( L1 r- a
31 encrypt((const ulong*)in, (ulong*)out); ! K( m& a* g# e5 Y9 e
32 }
: @, m$ j& I& z! A! A4 l( l33
- C7 l, o$ s" E0 d% M) [! d34 void TEA::decrypt(const byte *in, byte *out) { # @# V; g# K# m1 K1 u' w
35 decrypt((const ulong*)in, (ulong*)out);
$ B; h. `+ x! b* e1 Q5 N36 } 5 v) L5 B5 l4 t8 X( @" h8 d
37 * u8 R/ h l Y* W9 ]9 x
38 void TEA::encrypt(const ulong *in, ulong *out) {
: u7 k- K+ ~" U3 v/ S39 ! ]& g1 Y4 A5 H) q
40 ulong *k = (ulong*)_key;
% e- f# Y8 e: b! J- D# B5 N- y" ]41 register ulong y = ntoh(in[0]); A7 {+ ~8 `1 I; W6 e# w6 X/ ^' `) U
42 register ulong z = ntoh(in[1]); : \6 V6 D+ X/ T. Y& j$ J1 z! J$ o9 V
43 register ulong a = ntoh(k[0]); - C. G2 l. m, f% J; n
44 register ulong b = ntoh(k[1]); 5 |! u2 \, N: C: ~# h2 s
45 register ulong c = ntoh(k[2]); 2 k. u* n# C" B% @% B
46 register ulong d = ntoh(k[3]);
) L) H# z+ S9 k" n- m" g47 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
6 W( c/ Y' D0 {1 v4 I' D48 register int round = _round; ' X5 ]% T5 } X" j; r' i- Q% J5 y
49 register ulong sum = 0;
7 V4 C. n; H6 T k; B50
8 j' h- h+ {' X% o9 X! F; a( `51 while (round--) { /* basic cycle start */ 7 m, O( k P. c) o5 Y1 `
52 sum += delta;
0 c1 A+ g1 F+ d53 y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b); " h6 Y: a7 K0 Y2 h+ y# L8 l" a
54 z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
+ ~" N% |: X) x* }55 } /* end cycle */ 8 w3 r9 l/ K$ n( K7 g) X
56 out[0] = ntoh(y); " G4 B1 H& Z q6 o$ e
57 out[1] = ntoh(z); ! O- f' v6 w4 i" @& Y. A8 A
58 }
8 U" b9 N: n* w: W3 I' d1 _59
6 {0 |. _5 c% [- c1 g! C60 void TEA::decrypt(const ulong *in, ulong *out) {
: @; @3 Q0 `- u2 O2 x61
) {3 i$ G; _* Y3 _" ~62 ulong *k = (ulong*)_key; ; _2 Q) k/ w' N6 A( o9 A
63 register ulong y = ntoh(in[0]); 2 h& X/ T4 X* {& x$ T& v, {
64 register ulong z = ntoh(in[1]); 9 G! E+ n+ z8 i8 b6 s
65 register ulong a = ntoh(k[0]);
% Q! U+ p7 _' P. U2 n" |* f66 register ulong b = ntoh(k[1]); , g( u2 a9 P; n! W
67 register ulong c = ntoh(k[2]); 6 c- p) h. X* ?8 e: u' R% C
68 register ulong d = ntoh(k[3]);
2 N. d! P' T4 |6 p2 T6 p, B' ]7 N69 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */
7 a4 G% U+ Y W% U* i70 register int round = _round; ! ^6 T/ L, i& I. s2 w
71 register ulong sum = 0; % S0 {, F& S( T, j) C3 G
72
. T5 O# I- |2 ?8 ~73 if (round == 32)
d, k. ?2 T* T! W74 sum = 0xC6EF3720; /* delta << 5*/
6 j; H3 [7 F; [75 else if (round == 16)
% L3 \2 y6 M% U, a" t76 sum = 0xE3779B90; /* delta << 4*/ 7 s- E0 |8 x2 k9 j& C/ ?
77 else " n: t" _9 W0 p" ]# g, {
78 sum = delta << static_cast<int>(logbase(2, round)); ! Q4 c/ D5 O8 Q& u/ s6 i" U
79 0 ?1 n3 S. w6 n2 V7 l/ l/ D& U9 ^" ]
80 while (round--) { /* basic cycle start */
$ m- n6 q ^6 ]# t. H81 z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); 0 `! e+ E* Z7 Y* N1 V! X! q, [
82 y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b); - }$ e3 j8 t$ F) \
83 sum -= delta;
9 n9 @4 `( |7 B84 } /* end cycle */
7 P5 l* J" c- T8 r5 f( N85 out[0] = ntoh(y);
% o, E {( A0 @' k* P! e$ R9 [( e86 out[1] = ntoh(z); . p- J2 u D5 _' Y+ r1 b
87 }
9 s4 S v# H6 G, _" H. e0 t& q
$ X# r Q, k& I, G7 w需要说明的是TEA的构造函数: ! A' A; r2 b9 q; g3 k' F- X- n6 }8 F1 o
TEA(const byte *key, int round = 32, bool isNetByte = false); 1 a4 N9 B4 O0 g! B2 ~( E+ Z
1.key - 加密或解密用的128-bit(16byte)密钥。 : S3 V+ y) K+ F9 h, v% Q. }
2.round - 加密或解密的轮数,常用的有64,32,16。 , ~0 M& k* ^+ P/ Z9 p: o
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! . I9 J- ?2 I8 }5 o
5 }# Y7 A* d& x; z6 N& ~最后当然少不了测试代码: |
|