RC4演算法樣本

key為密鑰～

#include<iostream>#include<string>using namespace std;int s[256];int t[256];string key="0123456789";void swap(int* s1,int* s2){    int temp=*s1;    *s1=*s2;    *s2=temp;}void init(){    //初始化s和t數組    for(int i=0;i<256;i++){        s[i]=i;        t[i]=atoi(&(const char)(key.at(i%key.length())));    }    int j=0;    for(int i=0;i<256;i++){        j=(j+s[j]+t[j])%256;        swap(s+i,s+j);    }}void encode(int* start,int length){    int pos=0;    int i=0,j=0;    while(pos++<length){        i=(i+1)%256;        j=(j+s[i])%256;        swap(s+i,s+j);        int temp=(s[i]+s[j])%256;        int k=s[temp];        *start^=k;        start++;    }}void decode(int* start,int length){    encode(start,length);}void print(int* a,int length,string startMessage=""){    cout<<startMessage<<" ";    for(int i=0;i<length;i++){        cout<<*(a+i)<<" ";    }    cout<<endl;}int main(){    init();    int a[10]={0,1,2,3,4,5,6,7,8,9};    print(a,10,"原數組");    encode(a,10);    print(a,10,"加密後");    init();    decode(a,10);    print(a,10,"解密後");}