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发表于 2010-1-19 19:59:57
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tea.cpp
1 #include "tea.h" ) U/ ^; }& }+ ^
2 #include <cstring> //for memcpy,memset
# F4 T% n: E" a, G0 t, Y 3
& T. D9 g& _+ D8 a 4 using namespace std; 6 J6 D: Z0 w6 w9 F6 F4 D
5 & E: `' W# t' q% |( Y% Z$ ^
6 TEA::TEA(const byte *key, int round /*= 32*/, bool isNetByte /*= false*/) 5 n+ A: i( {! _) j0 ^& v, H
7 :_round(round) 6 O% ?; R+ ^8 D9 b
8 ,_isNetByte(isNetByte) {
; V8 |' [0 x& N; [$ {0 W 9 if (key != 0) / P* U# m q) t! P3 l' ~* m
10 memcpy(_key, key, 16); / q) b ~( X' X
11 else 6 K2 e/ m9 J* i1 o- w/ I: P
12 memset(_key, 0, 16);
h- ~+ `# M5 _" m13 }
) Y3 {! j% I2 h3 R/ U14
& n; |# M% h7 e7 F0 |: H ?4 t15 TEA::TEA(const TEA &rhs)
" I i$ q9 g) y' Q- ]16 :_round(rhs._round)
1 h. U& H* Y! b+ d17 ,_isNetByte(rhs._isNetByte) { ' K" M1 A: F1 ^
18 memcpy(_key, rhs._key, 16); - r: |+ z& j# N4 T
19 } 9 u" h3 Z' x* i' Y. i! Z' B. ?! f4 V
20 1 K8 w2 l" k" e) h+ ~8 m
21 TEA& TEA::operator=(const TEA &rhs) { * t0 N6 c' n3 B) N) z; K2 v6 T
22 if (&rhs != this) {
5 |/ T R6 s Y5 ?# `) H23 _round = rhs._round;
9 l! s7 z# L9 D8 Z& O& S1 u24 _isNetByte = rhs._isNetByte; ( e( x! y2 H' D7 r @* o
25 memcpy(_key, rhs._key, 16);
+ b2 l3 @$ ~. s26 }
; m. P$ t3 P- z27 return *this;
1 r& T8 r+ w' J/ I1 f+ D3 E$ V- z+ y28 } - K; ?" `" F: t: u
29 ' _# ?8 L+ m9 L ?, ?7 c3 |
30 void TEA::encrypt(const byte *in, byte *out) {
- J* }: V& N1 `' Z" t6 W31 encrypt((const ulong*)in, (ulong*)out); ( k7 }- |! ^ Y k/ T4 P
32 } $ F$ X, q7 |' K
33
% A( I+ ~! g, _, h. u34 void TEA::decrypt(const byte *in, byte *out) { + k; ~. T0 f, @3 A+ N- K
35 decrypt((const ulong*)in, (ulong*)out);
8 x# i' ~5 ?+ X {7 E9 ?36 }
% R+ A. o% x! n* w7 L" A37
6 E+ \9 m3 q! S5 m' S: {6 y+ B38 void TEA::encrypt(const ulong *in, ulong *out) {
' @; }2 z2 L) G8 _39 ( o( m+ m" w& z
40 ulong *k = (ulong*)_key;
- D+ G" Y2 R( U3 b41 register ulong y = ntoh(in[0]);
9 d$ s {) ?7 n" C% p; k42 register ulong z = ntoh(in[1]);
: r" m* J/ V7 C6 Z7 ?43 register ulong a = ntoh(k[0]);
7 G3 y" I# p- Y% M; ]7 B# u44 register ulong b = ntoh(k[1]);
4 n; B% _0 h$ H45 register ulong c = ntoh(k[2]); : ^8 B! n! e+ Z" y, O
46 register ulong d = ntoh(k[3]);
' P6 C! M% J- ]. a47 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */ 1 ?7 S& r) E% a
48 register int round = _round;
: X1 F+ b |" j49 register ulong sum = 0; $ s3 d1 \/ z4 ~: V! l/ B
50
! e" x. X! K0 J8 t, u( W1 m51 while (round--) { /* basic cycle start */ 7 X6 w+ n" Y7 y: s( z7 V: @4 w
52 sum += delta; / X% U) W* }7 `* G
53 y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
, m! v2 H6 a5 \; N, r1 ?54 z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); & b% B; {3 I$ A! W2 U$ A
55 } /* end cycle */ ; \9 e j) U7 F. B2 ?( H/ k3 y7 L
56 out[0] = ntoh(y); ( v$ k( c! W0 j5 K
57 out[1] = ntoh(z); / e7 b$ u; w. t6 \& s+ Z8 s/ w
58 }
! X+ ?1 X. g: U' q59 $ ~( y7 O# B, W5 c
60 void TEA::decrypt(const ulong *in, ulong *out) { 7 G+ V) h& \: C3 B" n- F
61
0 j! p) P9 A0 z# L8 \62 ulong *k = (ulong*)_key; $ z* C2 O5 A- r: F5 O; f3 o
63 register ulong y = ntoh(in[0]);
3 X8 I3 Y9 M( h3 V# x. q" n64 register ulong z = ntoh(in[1]);
% i7 s6 D" l7 U8 d6 y65 register ulong a = ntoh(k[0]);
% E% @" M4 W& n9 |& C/ C4 B) d+ I66 register ulong b = ntoh(k[1]);
+ h4 C" r! w4 o3 G. M7 d2 k67 register ulong c = ntoh(k[2]);
( {: c9 h$ h( }68 register ulong d = ntoh(k[3]);
! T8 v% O+ A- r! Z& Q/ I$ i69 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */ & l6 H/ v$ ]* i0 p! o& z1 T
70 register int round = _round; 4 j5 D# I o9 _0 [
71 register ulong sum = 0; % x, w8 U0 ^; T4 A
72
/ k* N7 q7 Z; G% K73 if (round == 32)
; v% s" ~" Q* C74 sum = 0xC6EF3720; /* delta << 5*/
9 {" h5 }3 h- o7 n* @, F8 V9 X' k75 else if (round == 16) - m. ?1 Q k7 U* E
76 sum = 0xE3779B90; /* delta << 4*/
4 I, I, i0 C' E8 l9 |7 f4 G8 O2 z, L77 else % [6 B2 J; J! X2 d
78 sum = delta << static_cast<int>(logbase(2, round));
9 [, p# N% v( A- F" m" C79 $ P! e3 G- q8 o: R5 w0 L
80 while (round--) { /* basic cycle start */
: g+ V* R3 ]. O2 @7 a81 z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); _0 M6 o- Y K# [
82 y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b); & K# v0 A7 u4 p) n6 @. p6 M5 g
83 sum -= delta; - Y2 e' o+ O; [% w5 I
84 } /* end cycle */
0 r2 h: o }; a' P85 out[0] = ntoh(y);
/ U x) W( ?/ e0 @# r86 out[1] = ntoh(z);
' j# p+ H1 i1 b" f8 @87 }
. B' |2 d8 F K$ w$ I: M5 F4 V3 p. { h! a X, v6 ^% H/ u
需要说明的是TEA的构造函数: % {# W3 p" J9 ^, H. y3 }
TEA(const byte *key, int round = 32, bool isNetByte = false); , P# B* W% B/ I( e+ Z$ B8 |
1.key - 加密或解密用的128-bit(16byte)密钥。
- L4 v& }3 v: h; r- |- y* {- j2.round - 加密或解密的轮数,常用的有64,32,16。
/ U2 J) }' F3 g7 g- L# B% E3.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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1 I8 Y/ k* Z) z: ~1 O2 M: _$ r% x最后当然少不了测试代码: |
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