大数运算(转)

[cpp]
Code:
/*****************************************************************
大数运算库头文件:BigInt.h
作者:afanty@vip.sina.com
版本:1.2 (2003.5.13)
说明:适用于MFC,1024位RSA运算
*****************************************************************/

//允许生成1120位(二进制)的中间结果
#ifndef BI_MAXLEN
#define BI_MAXLEN 35
#define DEC 10
#define HEX 16

class CBigInt
{
public:
//大数在0x100000000进制下的长度
unsigned m_nLength;
//用数组记录大数在0x100000000进制下每一位的值
unsigned long m_ulValue[BI_MAXLEN];

CBigInt();
~CBigInt();

/*****************************************************************
基本操作与运算
Mov,赋值运算,可赋值为大数或普通整数,可重载为运算符“=”
Cmp,比较运算,可重载为运算符“==”、“!=”、“>=”、“<=”等
Add,加,求大数与大数或大数与普通整数的和,可重载为运算符“+”
Sub,减,求大数与大数或大数与普通整数的差,可重载为运算符“-”
Mul,乘,求大数与大数或大数与普通整数的积,可重载为运算符“*”
Div,除,求大数与大数或大数与普通整数的商,可重载为运算符“/”
Mod,模,求大数与大数或大数与普通整数的模,可重载为运算符“%”
*****************************************************************/
void Mov(unsigned __int64 A);
void Mov(CBigInt& A);
CBigInt Add(CBigInt& A);
CBigInt Sub(CBigInt& A);
CBigInt Mul(CBigInt& A);
CBigInt Div(CBigInt& A);
CBigInt Mod(CBigInt& A);
CBigInt Add(unsigned long A);
CBigInt Sub(unsigned long A);
CBigInt Mul(unsigned long A);
CBigInt Div(unsigned long A);
unsigned long Mod(unsigned long A);
int Cmp(CBigInt& A);

/*****************************************************************
输入输出
Get,从字符串按10进制或16进制格式输入到大数
Put,将大数按10进制或16进制格式输出到字符串
*****************************************************************/
void Get(CString& str, unsigned int system=HEX);
void Put(CString& str, unsigned int system=HEX);

/*****************************************************************
RSA相关运算
Rab,拉宾米勒算法进行素数测试
Euc,欧几里德算法求解同余方程
RsaTrans,反复平方算法进行幂模运算
GetPrime,产生指定长度的随机大素数
*****************************************************************/
int Rab();
CBigInt Euc(CBigInt& A);
CBigInt RsaTrans(CBigInt& A, CBigInt& B);
void GetPrime(int bits);
};
#endif
/*****************************************************************
大数运算库源文件:BigInt.cpp
作者:afanty@vip.sina.com
版本:1.2 (2003.5.13)
说明:适用于MFC,1024位RSA运算
*****************************************************************/
#include "stdafx.h"
#include "BigInt.h"

//小素数表
const static int PrimeTable[550]=
{ 3, 5, 7, 11, 13, 17, 19, 23, 29, 31,
37, 41, 43, 47, 53, 59, 61, 67, 71, 73,
79, 83, 89, 97, 101, 103, 107, 109, 113, 127,
131, 137, 139, 149, 151, 157, 163, 167, 173, 179,
181, 191, 193, 197, 199, 211, 223, 227, 229, 233,
239, 241, 251, 257, 263, 269, 271, 277, 281, 283,
293, 307, 311, 313, 317, 331, 337, 347, 349, 353,
359, 367, 373, 379, 383, 389, 397, 401, 409, 419,
421, 431, 433, 439, 443, 449, 457, 461, 463, 467,
479, 487, 491, 499, 503, 509, 521, 523, 541, 547,
557, 563, 569, 571, 577, 587, 593, 599, 601, 607,
613, 617, 619, 631, 641, 643, 647, 653, 659, 661,
673, 677, 683, 691, 701, 709, 719, 727, 733, 739,
743, 751, 757, 761, 769, 773, 787, 797, 809, 811,
821, 823, 827, 829, 839, 853, 857, 859, 863, 877,
881, 883, 887, 907, 911, 919, 929, 937, 941, 947,
953, 967, 971, 977, 983, 991, 997, 1009, 1013, 1019,
1021, 1031, 1033, 1039, 1049, 1051, 1061, 1063, 1069, 1087,
1091, 1093, 1097, 1103, 1109, 1117, 1123, 1129, 1151, 1153,
1163, 1171, 1181, 1187, 1193, 1201, 1213, 1217, 1223, 1229,
1231, 1237, 1249, 1259, 1277, 1279, 1283, 1289, 1291, 1297,
1301, 1303, 1307, 1319, 1321, 1327, 1361, 1367, 1373, 1381,
1399, 1409, 1423, 1427, 1429, 1433, 1439, 1447, 1451, 1453,
1459, 1471, 1481, 1483, 1487, 1489, 1493, 1499, 1511, 1523,
1531, 1543, 1549, 1553, 1559, 1567, 1571, 1579, 1583, 1597,
1601, 1607, 1609, 1613, 1619, 1621, 1627, 1637, 1657, 1663,
1667, 1669, 1693, 1697, 1699, 1709, 1721, 1723, 1733, 1741,
1747, 1753, 1759, 1777, 1783, 1787, 1789, 1801, 1811, 1823,
1831, 1847, 1861, 1867, 1871, 1873, 1877, 1879, 1889, 1901,
1907, 1913, 1931, 1933, 1949, 1951, 1973, 1979, 1987, 1993,
1997, 1999, 2003, 2011, 2017, 2027, 2029, 2039, 2053, 2063,
2069, 2081, 2083, 2087, 2089, 2099, 2111, 2113, 2129, 2131,
2137, 2141, 2143, 2153, 2161, 2179, 2203, 2207, 2213, 2221,
2237, 2239, 2243, 2251, 2267, 2269, 2273, 2281, 2287, 2293,
2297, 2309, 2311, 2333, 2339, 2341, 2347, 2351, 2357, 2371,
2377, 2381, 2383, 2389, 2393, 2399, 2411, 2417, 2423, 2437,
2441, 2447, 2459, 2467, 2473, 2477, 2503, 2521, 2531, 2539,
2543, 2549, 2551, 2557, 2579, 2591, 2593, 2609, 2617, 2621,
2633, 2647, 2657, 2659, 2663, 2671, 2677, 2683, 2687, 2689,
2693, 2699, 2707, 2711, 2713, 2719, 2729, 2731, 2741, 2749,
2753, 2767, 2777, 2789, 2791, 2797, 2801, 2803, 2819, 2833,
2837, 2843, 2851, 2857, 2861, 2879, 2887, 2897, 2903, 2909,
2917, 2927, 2939, 2953, 2957, 2963, 2969, 2971, 2999, 3001,
3011, 3019, 3023, 3037, 3041, 3049, 3061, 3067, 3079, 3083,
3089, 3109, 3119, 3121, 3137, 3163, 3167, 3169, 3181, 3187,
3191, 3203, 3209, 3217, 3221, 3229, 3251, 3253, 3257, 3259,
3271, 3299, 3301, 3307, 3313, 3319, 3323, 3329, 3331, 3343,
3347, 3359, 3361, 3371, 3373, 3389, 3391, 3407, 3413, 3433,
3449, 3457, 3461, 3463, 3467, 3469, 3491, 3499, 3511, 3517,
3527, 3529, 3533, 3539, 3541, 3547, 3557, 3559, 3571, 3581,
3583, 3593, 3607, 3613, 3617, 3623, 3631, 3637, 3643, 3659,
3671, 3673, 3677, 3691, 3697, 3701, 3709, 3719, 3727, 3733,
3739, 3761, 3767, 3769, 3779, 3793, 3797, 3803, 3821, 3823,
3833, 3847, 3851, 3853, 3863, 3877, 3881, 3889, 3907, 3911,
3917, 3919, 3923, 3929, 3931, 3943, 3947, 3967, 3989, 4001
};

//构造大数对象并初始化为零
CBigInt::CBigInt()
{
m_nLength=1;
for(int i=0;i<BI_MAXLEN;i++)m_ulValue[i]=0;
}

//解构大数对象
CBigInt::~CBigInt()
{
}

/****************************************************************************************
大数比较
调用方式:N.Cmp(A)
返回值:若N<A返回-1;若N=A返回0;若N>A返回1
****************************************************************************************/
int CBigInt::Cmp(CBigInt& A)
{
if(m_nLength>A.m_nLength)return 1;
if(m_nLength<A.m_nLength)return -1;
for(int i=m_nLength-1;i>=0;i–)
{
if(m_ulValue[i]>A.m_ulValue[i])return 1;
if(m_ulValue[i]<A.m_ulValue[i])return -1;
}
return 0;
}

/****************************************************************************************
大数赋值
调用方式:N.Mov(A)
返回值:无,N被赋值为A
****************************************************************************************/
void CBigInt::Mov(CBigInt& A)
{
m_nLength=A.m_nLength;
for(int i=0;i<BI_MAXLEN;i++)m_ulValue[i]=A.m_ulValue[i];
}

void CBigInt::Mov(unsigned __int64 A)
{
if(A>0xffffffff)
{
m_nLength=2;
m_ulValue[1]=(unsigned long)(A>>32);
m_ulValue[0]=(unsigned long)A;
}
else
{
m_nLength=1;
m_ulValue[0]=(unsigned long)A;
}
for(int i=m_nLength;i<BI_MAXLEN;i++)m_ulValue[i]=0;
}

/****************************************************************************************
大数相加
调用形式:N.Add(A)
返回值:N+A
****************************************************************************************/
CBigInt CBigInt::Add(CBigInt& A)
{
CBigInt X;
X.Mov(*this);
unsigned carry=0;
unsigned __int64 sum=0;
if(X.m_nLength<A.m_nLength)X.m_nLength=A.m_nLength;
for(unsigned i=0;i<X.m_nLength;i++)
{
sum=A.m_ulValue[i];
sum=sum+X.m_ulValue[i]+carry;
X.m_ulValue[i]=(unsigned long)sum;
carry=(unsigned)(sum>>32);
}
X.m_ulValue[X.m_nLength]=carry;
X.m_nLength+=carry;
return X;
}

CBigInt CBigInt::Add(unsigned long A)
{
CBigInt X;
X.Mov(*this);
unsigned __int64 sum;
sum=X.m_ulValue[0];
sum+=A;
X.m_ulValue[0]=(unsigned long)sum;
if(sum>0xffffffff)
{
unsigned i=1;
while(X.m_ulValue[i]==0xffffffff){X.m_ulValue[i]=0;i++;}
X.m_ulValue[i]++;
if(m_nLength==i)m_nLength++;
}
return X;
}

/****************************************************************************************
大数相减
调用形式:N.Sub(A)
返回值:N-A
****************************************************************************************/
CBigInt CBigInt::Sub(CBigInt& A)
{
CBigInt X;
X.Mov(*this);
if(X.Cmp(A)<=0){X.Mov(0);return X;}
unsigned carry=0;
unsigned __int64 num;
unsigned i;
for(i=0;i<m_nLength;i++)
{
if((m_ulValue[i]>A.m_ulValue[i])||((m_ulValue[i]==A.m_ulValue[i])&&(carry==0)))
{
X.m_ulValue[i]=m_ulValue[i]-carry-A.m_ulValue[i];
carry=0;
}
else
{
num=0x100000000+m_ulValue[i];
X.m_ulValue[i]=(unsigned long)(num-carry-A.m_ulValue[i]);
carry=1;
}
}
while(X.m_ulValue[X.m_nLength-1]==0)X.m_nLength–;
return X;
}

CBigInt CBigInt::Sub(unsigned long A)
{
CBigInt X;
X.Mov(*this);
if(X.m_ulValue[0]>=A){X.m_ulValue[0]-=A;return X;}
if(X.m_nLength==1){X.Mov(0);return X;}
unsigned __int64 num=0x100000000+X.m_ulValue[0];
X.m_ulValue[0]=(unsigned long)(num-A);
int i=1;
while(X.m_ulValue[i]==0){X.m_ulValue[i]=0xffffffff;i++;}
X.m_ulValue[i]–;
if(X.m_ulValue[i]==0)X.m_nLength–;
return X;
}

/****************************************************************************************
大数相乘
调用形式:N.Mul(A)
返回值:N*A
****************************************************************************************/
CBigInt CBigInt::Mul(CBigInt& A)
{
if(A.m_nLength==1)return Mul(A.m_ulValue[0]);
CBigInt X;
unsigned __int64 sum,mul=0,carry=0;
unsigned i,j;
X.m_nLength=m_nLength+A.m_nLength-1;
for(i=0;i<X.m_nLength;i++)
{
sum=carry;
carry=0;
for(j=0;j<A.m_nLength;j++)
{
if(((i-j)>=0)&&((i-j)<m_nLength))
{
mul=m_ulValue[i-j];
mul*=A.m_ulValue[j];
carry+=mul>>32;
mul=mul&0xffffffff;
sum+=mul;
}
}
carry+=sum>>32;
X.m_ulValue[i]=(unsigned long)sum;
}
if(carry){X.m_nLength++;X.m_ulValue[X.m_nLength-1]=(unsigned long)carry;}
return X;
}

CBigInt CBigInt::Mul(unsigned long A)
{
CBigInt X;
unsigned __int64 mul;
unsigned long carry=0;
X.Mov(*this);
for(unsigned i=0;i<m_nLength;i++)
{
mul=m_ulValue[i];
mul=mul*A+carry;
X.m_ulValue[i]=(unsigned long)mul;
carry=(unsigned long)(mul>>32);
}
if(carry){X.m_nLength++;X.m_ulValue[X.m_nLength-1]=carry;}
return X;
}

/****************************************************************************************
大数相除
调用形式:N.Div(A)
返回值:N/A
****************************************************************************************/
CBigInt CBigInt::Div(CBigInt& A)
{
if(A.m_nLength==1)return Div(A.m_ulValue[0]);
CBigInt X,Y,Z;
unsigned i,len;
unsigned __int64 num,div;
Y.Mov(*this);
while(Y.Cmp(A)>=0)
{
div=Y.m_ulValue[Y.m_nLength-1];
num=A.m_ulValue[A.m_nLength-1];
len=Y.m_nLength-A.m_nLength;
if((div==num)&&(len==0)){X.Mov(X.Add(1));break;}
if((div<=num)&&len){len–;div=(div<<32)+Y.m_ulValue[Y.m_nLength-2];}
div=div/(num+1);
Z.Mov(div);
if(len)
{
Z.m_nLength+=len;
for(i=Z.m_nLength-1;i>=len;i–)Z.m_ulValue[i]=Z.m_ulValue[i-len];
for(i=0;i<len;i++)Z.m_ulValue[i]=0;
}
X.Mov(X.Add(Z));
Y.Mov(Y.Sub(A.Mul(Z)));
}
return X;
}

CBigInt CBigInt::Div(unsigned long A)
{
CBigInt X;
X.Mov(*this);
if(X.m_nLength==1){X.m_ulValue[0]=X.m_ulValue[0]/A;return X;}
unsigned __int64 div,mul;
unsigned long carry=0;
for(int i=X.m_nLength-1;i>=0;i–)
{
div=carry;
div=(div<<32)+X.m_ulValue[i];
X.m_ulValue[i]=(unsigned long)(div/A);
mul=(div/A)*A;
carry=(unsigned long)(div-mul);
}
if(X.m_ulValue[X.m_nLength-1]==0)X.m_nLength–;
return X;
}

/****************************************************************************************
大数求模
调用形式:N.Mod(A)
返回值:N%A
****************************************************************************************/
CBigInt CBigInt::Mod(CBigInt& A)
{
CBigInt X,Y;
unsigned __int64 div,num;
unsigned long carry=0;
unsigned i,len;
X.Mov(*this);
while(X.Cmp(A)>=0)
{
div=X.m_ulValue[X.m_nLength-1];
num=A.m_ulValue[A.m_nLength-1];
len=X.m_nLength-A.m_nLength;
if((div==num)&&(len==0)){X.Mov(X.Sub(A));break;}
if((div<=num)&&len){len–;div=(div<<32)+X.m_ulValue[X.m_nLength-2];}
div=div/(num+1);
Y.Mov(div);
Y.Mov(A.Mul(Y));
if(len)
{
Y.m_nLength+=len;
for(i=Y.m_nLength-1;i>=len;i–)Y.m_ulValue[i]=Y.m_ulValue[i-len];
for(i=0;i<len;i++)Y.m_ulValue[i]=0;
}
X.Mov(X.Sub(Y));
}
return X;
}

unsigned long CBigInt::Mod(unsigned long A)
{
if(m_nLength==1)return(m_ulValue[0]%A);
unsigned __int64 div;
unsigned long carry=0;
for(int i=m_nLength-1;i>=0;i–)
{
div=m_ulValue[i];
div+=carry*0x100000000;
carry=(unsigned long)(div%A);
}
return carry;
}

/****************************************************************************************
从字符串按10进制或16进制格式输入到大数
调用格式:N.Get(str,sys)
返回值:N被赋值为相应大数
sys暂时只能为10或16
****************************************************************************************/
void CBigInt::Get(CString& str, unsigned int system)
{
int len=str.GetLength(),k;
Mov(0);
for(int i=0;i<len;i++)
{
Mov(Mul(system));
if((str[i]>=’0′)&&(str[i]<=’9′))k=str[i]-48;
else if((str[i]>=’A’)&&(str[i]<=’F’))k=str[i]-55;
else if((str[i]>=’a’)&&(str[i]<=’f’))k=str[i]-87;
else k=0;
Mov(Add(k));
}
}

/****************************************************************************************
将大数按10进制或16进制格式输出为字符串
调用格式:N.Put(str,sys)
返回值:无,参数str被赋值为N的sys进制字符串
sys暂时只能为10或16
****************************************************************************************/
void CBigInt::Put(CString& str, unsigned int system)
{
if((m_nLength==1)&&(m_ulValue[0]==0)){str="0";return;}
str="";
CString t="0123456789ABCDEF";
int a;
char ch;
CBigInt X;
X.Mov(*this);
while(X.m_ulValue[X.m_nLength-1]>0)
{
a=X.Mod(system);
ch=t[a];
str.Insert(0,ch);
X.Mov(X.Div(system));
}
}

/****************************************************************************************
求不定方程ax-by=1的最小整数解
调用方式:N.Euc(A)
返回值:X,满足:NX mod A=1
****************************************************************************************/
CBigInt CBigInt::Euc(CBigInt& A)
{
CBigInt M,E,X,Y,I,J;
int x,y;
M.Mov(A);
E.Mov(*this);
X.Mov(0);
Y.Mov(1);
x=y=1;
while((E.m_nLength!=1)||(E.m_ulValue[0]!=0))
{
I.Mov(M.Div(E));
J.Mov(M.Mod(E));
M.Mov(E);
E.Mov(J);
J.Mov(Y);
Y.Mov(Y.Mul(I));
if(x==y)
{
if(X.Cmp(Y)>=0)Y.Mov(X.Sub(Y));
else{Y.Mov(Y.Sub(X));y=0;}
}
else{Y.Mov(X.Add(Y));x=1-x;y=1-y;}
X.Mov(J);
}
if(x==0)X.Mov(A.Sub(X));
return X;
}

/****************************************************************************************
求乘方的模
调用方式:N.RsaTrans(A,B)
返回值:X=N^A MOD B
****************************************************************************************/
CBigInt CBigInt::RsaTrans(CBigInt& A, CBigInt& B)
{
CBigInt X,Y;
int i,j,k;
unsigned n;
unsigned long num;
k=A.m_nLength*32-32;
num=A.m_ulValue[A.m_nLength-1];
while(num){num=num>>1;k++;}
X.Mov(*this);
for(i=k-2;i>=0;i–)
{
Y.Mov(X.Mul(X.m_ulValue[X.m_nLength-1]));
Y.Mov(Y.Mod(B));
for(n=1;n<X.m_nLength;n++)
{
for(j=Y.m_nLength;j>0;j–)Y.m_ulValue[j]=Y.m_ulValue[j-1];
Y.m_ulValue[0]=0;
Y.m_nLength++;
Y.Mov(Y.Add(X.Mul(X.m_ulValue[X.m_nLength-n-1])));
Y.Mov(Y.Mod(B));
}
X.Mov(Y);
if((A.m_ulValue[i>>5]>>(i&31))&1)
{
Y.Mov(Mul(X.m_ulValue[X.m_nLength-1]));
Y.Mov(Y.Mod(B));
for(n=1;n<X.m_nLength;n++)
{
for(j=Y.m_nLength;j>0;j–)Y.m_ulValue[j]=Y.m_ulValue[j-1];
Y.m_ulValue[0]=0;
Y.m_nLength++;
Y.Mov(Y.Add(Mul(X.m_ulValue[X.m_nLength-n-1])));
Y.Mov(Y.Mod(B));
}
X.Mov(Y);
}
}
return X;
}

/****************************************************************************************
拉宾米勒算法测试素数
调用方式:N.Rab()
返回值:若N为素数,返回1,否则返回0
****************************************************************************************/
int CBigInt::Rab()
{
unsigned i,j,pass;
for(i=0;i<550;i++){if(Mod(PrimeTable[i])==0)return 0;}
CBigInt S,A,I,K;
K.Mov(*this);
K.m_ulValue[0]–;
for(i=0;i<5;i++)
{
pass=0;
A.Mov(rand()*rand());
S.Mov(K);
while((S.m_ulValue[0]&1)==0)
{
for(j=0;j<S.m_nLength;j++)
{
S.m_ulValue[j]=S.m_ulValue[j]>>1;
if(S.m_ulValue[j+1]&1)S.m_ulValue[j]=S.m_ulValue[j]|0x80000000;
}
if(S.m_ulValue[S.m_nLength-1]==0)S.m_nLength–;
I.Mov(A.RsaTrans(S,*this));
if(I.Cmp(K)==0){pass=1;break;}
}
if((I.m_nLength==1)&&(I.m_ulValue[0]==1))pass=1;
if(pass==0)return 0;
}
return 1;
}

/****************************************************************************************
产生随机素数
调用方法:N.GetPrime(bits)
返回值:N被赋值为一个bits位(0x100000000进制长度)的素数
****************************************************************************************/
void CBigInt::GetPrime(int bits)
{
unsigned i;
m_nLength=bits;
begin:
for(i=0;i<m_nLength;i++)m_ulValue[i]=rand()*0x10000+rand();
m_ulValue[0]=m_ulValue[0]|1;
for(i=m_nLength-1;i>0;i–)
{
m_ulValue[i]=m_ulValue[i]<<1;
if(m_ulValue[i-1]&0x80000000)m_ulValue[i]++;
}
m_ulValue[0]=m_ulValue[0]<<1;
m_ulValue[0]++;
for(i=0;i<550;i++){if(Mod(PrimeTable[i])==0)goto begin;}
CBigInt S,A,I,K;
K.Mov(*this);
K.m_ulValue[0]–;
for(i=0;i<5;i++)
{
A.Mov(rand()*rand());
S.Mov(K.Div(2));
I.Mov(A.RsaTrans(S,*this));
if(((I.m_nLength!=1)||(I.m_ulValue[0]!=1))&&(I.Cmp(K)!=0))goto begin;
}
}
[/cpp]

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