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一开始不知道有biginteger这个大数类，居然自己去实现了一个，写了大数加法后，才发现有现成的t_t 以下是引用片段：
package rsa;
import java.math.biginteger;
public class rsa {
private long p,q,e,d,n;
public rsa(){
int pindex = (int)(math.random()*10);
int qindex;
int eindex;
do{
qindex = (int)(math.random()*10);
}
while(qindex==pindex);
do{
eindex = (int)(math.random()*10);
}
while(eindex==pindex||eindex==pindex);
p = 1033;
q = 2017;
e = 29437;
n = p*q;
d = calculated();
}
private long calculated(){
long t0 = 0,t1 = 1,t2 = -1;
long r0 = (p-1)*(q-1), m = r0,r1 = e ,r2 = -1;
do{
long q = r0/r1;
r2 = r0-r1*q;
if(r2==0)break;
t2 = t0 - t1*q;
while(t2<0){
t2+=m;
}
if(t2>=m){
t2 %= m;
}
r0 = r1;
r1 = r2;
t0 = t1;
t1 = t2;
}while(r2!=0);
if(r1!=1){
return 0;
}
else{
return t2;
}
}
public long gete() {
return e;
}
public long getn() {
return n;
}
public long getd() {
return d;
}
public biginteger encode(biginteger data){
return pow(data,d).mod(new biginteger(n+""));
}
public biginteger decode(biginteger code){
return pow(code,e).mod(new biginteger(n+""));
}
public biginteger pow(biginteger data,long p){
data = data.pow((int)p);
return data;
}
public static void main(string args[]){
rsa rsa = new rsa();
biginteger data = new biginteger("222222");
long oldtime = system.currenttimemillis();
biginteger code = rsa.encode(data);
long newtime = system.currenttimemillis();
double codetime = ((double)(newtime-oldtime))/1000;
oldtime = system.currenttimemillis();
biginteger decode = rsa.decode(code);
newtime = system.currenttimemillis();
double decodetime = ((double)(newtime-oldtime))/1000;
system.out.println("privatekey:"+rsa.d);
system.out.println("publickkey:"+rsa.e);
system.out.println("n:"+rsa.n);
system.out.println("data:"+data);
system.out.println("code:"+code+" time:"+codetime);
system.out.println("decode:"+decode+" time:"+decodetime);
}
} |
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