rsa.rar_RSA encryption _rsa_rsa c++

{\rtf1\ansi\ansicpg1252\deff0\deflang1033{\fonttbl{\f0\fswiss\fcharset0 Arial;}} {\*\generator Msftedit 5.41.15.1515;}\viewkind4\uc1\pard\f0\fs20 #include<iostream.h>\par #include<stdio.h>\par #include<stdlib.h>\par #include<string.h>\par #include<conio.h>\par #include<math.h>\par #include<process.h>\par \par class RSA\par \{\par public:\par int pr1,pr2,x1,n,n1;\par int e,d,pt;\par int a[20],b[10];\par int len; //binary array length\par \par RSA();\par \par //Miller & Rabin Algorithm--Test for Primality\par void testprimality();\par \par //PseudoRandom Number Generator Algorithm\par void pseudo1();\par int pseudo2();\par \par //Relatively Prime--Euclid's Algorithm\par //GCD of two numbers-their common factor is '1'\par void relprime();\par int gcd(int c,int d);\par \par //Key Generation\par int keygenerate1(int ptext);//for Encryption\par int keygenerate2(int ctext);//for Decryption\par void decitobin(int x);\par \par //Encryption\par int encrypt(int num);\par \par //Decryption\par int decrypt(int ctext);\par \par \par \par \};\par \par \par //Interface File--RSA Application\par //Miller & Rabin Algorithm--Test for Primality\par //PseudoRandom Number Generator Algorithm\par //Relatively Prime--Euclid's Algorithm\par \par #include"rh1.h"\par \par RSA::RSA()\par \{\par x1=1;\par pr1=0;\par pr2=0;\par \}\par \par //Miller & Rabin Algorithm--Test for Primality\par \par void RSA::testprimality()\par \{\par int a,j,p1,q,x;\par int t1,t2;\par \par int k,flag,ch;\par \par ch=1;\par flag=0;\par k=0;\par \par //(n-1)=pow(2,k)*q\par //divide (n-1) by 2 until result is odd number\par \par while(ch)\par \{\par x=(n-1)/(int)(pow(2,k));\par if(fmod(x,2)==1)\par \{\par ch=0;\par break;\par \}\par \par k++;\par \}\par \par q=(int)((n-1)/(pow(2,k)));\par \par //to pick an integer randomly which\par //should be less than 'n';\par //That's why calling pseudo2()\par a=pseudo2();\par \par if(a>1 && a<(n-1))\par \{\par t1=(int)(pow(a,q));\par \par if((t1%n)==1)\par flag=1;\par else\par \{\par \par for(j=0;j<=(k-1);j++)\par \{\par p1=((int)(pow(2,j)))*q;\par t2=(int)pow(a,p1);\par \par if((t2%n)==(n-1))\par flag=1;\par \par \}\par \}\par \}\par \par if(flag==1)\par if(pr1==0)\par pr1=n;\par else if(pr1!=0 && pr2==0)\par pr2=n;\par \par \}\par \par //PseudoRandom Number Generator Algorithm\par \par void RSA::pseudo1()\par \{\par //to select 'n' pseudorandomly and pass to testprimality();\par //'n' is to be proved either prime or not prime\par \par int a,c,y;\par unsigned int m;\par \par y=0;\par \par a=(int)pow(7,5); //(7,2),*(7,4),(7,5)\par //(int)pow(7,5) used in IBM 360\par \par //m should be assigned a "prime" no.\par //up to pow(2,31) should be used.\par //(2,5)-1;(2,7)-1;(2,13)-1;\par //(2,17)-1;(2,19)-1;(2,31)-1 are primes\par \par m=((int)pow(2,7))-1; //(2,7)\par \par n=1;c=0;\par \par for(int i=0;i<50;i++)\par \{\par n=((a*n)+c)%m;\par testprimality();\par //n will be computed in textprimality()\par \}\par \par // cout<<"\par pr1 = "<<pr1;\par // cout<<"\par pr2 = "<<pr2;\par \}\par \par int RSA::pseudo2()\par \{\par //to pick an integer randomly which\par //should be less than 'n'\par \par int a,ret;\par unsigned int m;\par \par a=(int)pow(7,4); //(7,3),*(7,4) for a's (7,5)in pseudo1\par m=(int)pow(2,5)-1; //(2,5)\par \par ret=(a*x1)%m;\par x1=ret;\par \par return ret;\par \par \}\par \par //Relatively Prime--Euclid's Algorithm\par //GCD of two numbers-their common factor is '1'\par void RSA::relprime()\par \{\par \par //Finding 'e' & 'd' value\par int fin,ret,ret1,ret2,ch,ex,dx;\par \par ch=1;ex=2;dx=1;\par n1=pr1*pr2;\par \par fin=(pr1-1)*(pr2-1);\par \par //Finding 'e' alone\par x1=1; //for pseudo2\par \par while(ch)\par \{\par ex=pseudo2();\par if(ex>1 && ex<fin)\par \{\par ret1=gcd(ex,fin);\par ret2=gcd(fin,(ex%fin));\par if(ret1==1 && ret2==1)\par \{\par e=ex;\par ch=0;\par break;\par \}\par \}\par \par \}\par \par // cout<<"\par Relative Prime : e value: "<<e;\par \par //Finding 'd' alone\par //de=(1 mod fin) where fin=(pr1-1)*(pr2-1);\par ch=1;\par while(ch)\par \{\par ret=(e*dx)%fin;\par if(ret==1)\par \{\par d=dx;\par ch=0;\par break;\par \}\par dx=dx+1;\par \par \}\par \par // cout<<"\par d value : "<<d;\par \}\par \par int RSA::gcd(int c,int d)\par \{\par int r;\par \par r=d%c;\par \par while(r!=0)\par \{\par d=c;\par c=r;\par r=d%c;\par \}\par \par return c;\par \}\par \par int RSA::keygenerate1(int ptext)\par \{\par //Encryption\par int i,c;\par int entext;\par \par c=0;entext=1;\par \par decitobin(e); //public key with 'e'\par //b[]->array contains binary value of 'e'\par \par for(i=len;i>=0;i--)\par \{\par c=2*c;\par entext=(entext*entext)%n1; //187->n1\par if(a[i]==1)\par \{\par c=c+1;\par entext=(entext*ptext)%n1; //187->n1\par \}\par \}\par \par // cout<<"\par Encrypted 'c' : "<<c;\par return entext;\par \}\par \par int RSA::keygenerate2(int ctext)\par \{\par \par //Decryption\par int i,dntext,c;\par dntext=1;\par c=0;\par \par decitobin(d); //Private Key with 'd'\par //b[]->array contains binary value of 'd'\par \par \par for(i=len;i>=0;i--)\par \{\par c=2*c;\par dntext=(dntext*dntext)%n1;\par \par if(a[i]==1)\par \{\par c=c+1;\par dntext=(dntext*ctext)%n1;\par \}\par \par \}\par \par // cout<<"\par Decrypted 'c' := "<<c;\par \par return dntext;\par \}\par \par \par void RSA::decitobin(int x)\par \{\par int k,i=0;\par \par while(x>0)\par \{\par a[i]=x%2;\par i++;\par x=x/2;\par \}\par \par //when exit from above loop, i value is incremented by 1\par k=i-1;\par \par len=i-1;\par \}\par \par \par int RSA::encrypt(int num)\par \{\par int ctext,i;\par \par pt=num;\par ctext=keygenerate1(num);\par \par return(ctext);\par \}\par \par int RSA::decrypt(int ctext)\par \{\par int dectext,i;\par \par dectext=keygenerate2(ctext);\par \par return(dectext);\par \par \}\par \par \par \par \par //Application File--RSA Application\par //Miller & Rabin Algorithm--Test for Primality\par //PseudoRandom Number Generator Algorithm\par //Relatively Prime--Euclid's Algorithm\par \par #include"rh1.h"\par #include<stdio.h>\par \par void main()\par \{\par int i,det,det1,len,k,k1,cnt;\par int con=0,c;\par char ch[100],cipher[20],orig[20];\par \par RSA r;\par c=1;\par \par cout<<endl<<endl;\par for(i=0;i<70;i++)\par cout<<'*';\par cout<<"\par RSA APPLICATION<BR>;\par for(i=0;i<70;i++)\par cout<<'*';\par cout<<endl;\par \par \par r.pseudo1();\par r.relprime();\par \par cout<<"\par \par Enter the String : ";\par cnt=0;\par char chr;\par \par scanf ( "%[^\par ]s", ch ) ;\par \par \par len=strlen(ch);\par k=0;k1=0;\par \par for(i=0;i<len;i++)\par \{\par con=(int)ch[i];\par det=r.encrypt(con);\par cipher[k]=char(det);\par k++;\par det1=r.decrypt(det);\par orig[k1]=char(det1);\par k1++;\par \}\par \par cipher[k]='\par } http://en.pudn.com/downloads72/sourcecode/crypt/detail263990_en.html