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发表于 2010-1-19 19:59:57
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tea.cpp
1 #include "tea.h" 4 u5 ^* I- @% X. f1 K5 ~. O
2 #include <cstring> //for memcpy,memset
3 V! g0 H8 {$ z* S, W( A/ Y 3
/ a3 ?3 ?( T9 N5 v! P; Q 4 using namespace std; i+ G4 n1 K- H: `
5
u3 u/ f( s* A, }- @ 6 TEA::TEA(const byte *key, int round /*= 32*/, bool isNetByte /*= false*/)
) R' `# q3 K4 Q- U& } 7 :_round(round) $ A0 b8 l8 E. ?/ c0 C5 Z
8 ,_isNetByte(isNetByte) { ( c0 o5 G( A- s0 A% G9 w4 ?. v4 ]
9 if (key != 0)
/ K' u& i1 A7 R+ T/ M10 memcpy(_key, key, 16);
. {/ {0 c/ R( J8 Y7 _11 else
3 ^- K3 O- l8 i5 l12 memset(_key, 0, 16);
8 A4 w6 K# J; b8 `13 }
. ]2 `0 c9 t/ j3 r1 y14 7 t' h- u$ W2 i) H9 u
15 TEA::TEA(const TEA &rhs)
& z1 Y( z: ]" p( p( E16 :_round(rhs._round) ) M7 b/ R+ H: [' w* p6 x |
17 ,_isNetByte(rhs._isNetByte) { 1 j: q- `. C, |& M+ M% L% d1 z
18 memcpy(_key, rhs._key, 16);
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20 + b+ G. V0 Q5 b* b9 I* q7 U
21 TEA& TEA::operator=(const TEA &rhs) {
: v# k7 t O# ^! M2 B7 D22 if (&rhs != this) {
' d6 S6 R3 L) \$ Q23 _round = rhs._round; ! z* l5 a( Y" j0 ^4 Z
24 _isNetByte = rhs._isNetByte; ; V1 F( l5 ]; T j) S7 v0 b- {6 d
25 memcpy(_key, rhs._key, 16); + F9 F( f- A J- x0 R& [
26 } $ u. N' A& R* i: `9 @ m
27 return *this; 6 {, M/ m W) }
28 } ; N, J1 y# O6 r4 |& o
29 + h# } c. r0 j$ u$ d8 P
30 void TEA::encrypt(const byte *in, byte *out) { % a( M0 K- R* c3 l* l6 s6 S: z% T0 c
31 encrypt((const ulong*)in, (ulong*)out);
- V' x9 }8 P/ l& ?* ]32 }
9 w( S4 t) o+ M' e) m, f: V2 L# {33
' U9 v7 V+ I, c: G34 void TEA::decrypt(const byte *in, byte *out) { 1 a1 P# B$ p% \3 T
35 decrypt((const ulong*)in, (ulong*)out);
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37
' z# @% Y8 b2 h& }8 ~9 D38 void TEA::encrypt(const ulong *in, ulong *out) {
, q' d, D: ~" l39 + M4 N9 Q! j' f- P/ ~
40 ulong *k = (ulong*)_key;
! B3 n& C8 H% G41 register ulong y = ntoh(in[0]);
* }$ }9 Q3 e; W# Z, n42 register ulong z = ntoh(in[1]);
1 e/ @8 f! z8 ], Q/ A43 register ulong a = ntoh(k[0]); 6 c6 {( \$ N' d7 H2 `+ k7 f2 z
44 register ulong b = ntoh(k[1]);
6 r1 p( R4 W) Q45 register ulong c = ntoh(k[2]); ! m- A0 t/ s" T( i
46 register ulong d = ntoh(k[3]); ; o, x+ T! N& q! \8 d
47 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */ 5 j/ C: h7 T1 {- z8 [6 C
48 register int round = _round; a8 ~' E* T4 p/ t
49 register ulong sum = 0;
& X$ G% J9 O! `, E6 f/ a50
1 g1 @9 M' \/ [" A/ \+ E2 B51 while (round--) { /* basic cycle start */
5 q4 R9 [' b7 w52 sum += delta;
- l! V. n; I1 _+ T H53 y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
7 J% z, C3 _. W54 z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); % f) `- V# ]) X& m$ S/ v6 W+ G
55 } /* end cycle */ # o. F3 E j8 x/ q& ~
56 out[0] = ntoh(y); " b$ Q# v3 P1 Y
57 out[1] = ntoh(z);
( y+ v6 z( r, z* _1 z8 b$ t" i58 } ' t6 u8 [3 j @6 B5 [
59
4 A" {: e0 ~$ {* l60 void TEA::decrypt(const ulong *in, ulong *out) {
) r* ]* V6 r) p6 B Z61
1 X% b) M1 O: F. D% O62 ulong *k = (ulong*)_key;
- W# _+ [, X. K4 W, ], G63 register ulong y = ntoh(in[0]);
4 n( P+ H* h3 u1 ]7 ~: O64 register ulong z = ntoh(in[1]);
2 |" y; _3 _% i/ Z7 i65 register ulong a = ntoh(k[0]); . ]$ R+ f: G7 k& p6 u
66 register ulong b = ntoh(k[1]);
4 j0 v# d( z1 G3 P6 a' B0 }; Q3 j67 register ulong c = ntoh(k[2]);
5 ?5 W% l1 t6 i) w5 z, C5 b68 register ulong d = ntoh(k[3]); ! ~/ X1 j. o% R0 x0 d
69 register ulong delta = 0x9E3779B9; /* (sqrt(5)-1)/2*2^32 */ " g1 ?( }- m& G& V* L B* K
70 register int round = _round;
2 [& S( A+ {0 e; \71 register ulong sum = 0;
5 t! M/ W% t8 Y+ J) U72 i. }- D j) w6 c* H' Z5 {: ~
73 if (round == 32)
& z: f1 k% g, H! [$ r" d74 sum = 0xC6EF3720; /* delta << 5*/ . d; N/ e* f) F$ ^/ C
75 else if (round == 16) ' e8 K( _0 t' q6 w0 f
76 sum = 0xE3779B90; /* delta << 4*/
( t4 P6 X$ ?8 g4 X6 v2 ? O77 else
8 w! k: d' t5 m8 y( \( Q78 sum = delta << static_cast<int>(logbase(2, round));
% ]" w; N" \+ s- U79 4 P! [3 b+ a1 p& n, _1 [7 d
80 while (round--) { /* basic cycle start */
) Z) h6 B# M0 M, @. G) D- ~81 z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d); * {0 W# m1 R$ ]* O$ E
82 y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
) U- ^+ b3 H7 U% N$ \83 sum -= delta;
/ |: T" Z4 j! W+ G) x84 } /* end cycle */
9 d5 H8 [: N+ E. u- w, I85 out[0] = ntoh(y); 2 Z% U3 {0 _" E+ ?4 b/ n2 i
86 out[1] = ntoh(z); . x4 u+ h" i+ |
87 }
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需要说明的是TEA的构造函数: 6 {0 M$ k7 T$ ~1 s
TEA(const byte *key, int round = 32, bool isNetByte = false); 2 T- i. P/ q, D
1.key - 加密或解密用的128-bit(16byte)密钥。
R3 C& S8 \# q4 Q9 j! F2.round - 加密或解密的轮数,常用的有64,32,16。 ' `: C z Y' S, }
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!
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$ R$ Z2 Z: O5 X: y最后当然少不了测试代码: |
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