我正在开发一个用c ++实现RSA算法的项目,之前我不知道c ++,但我还在学习, 我在RSA中的问题是如何将字符编码为0-25之间的数字: 编码为0, b到1, c到2, 。 。 z到25,
这是我的代码:
/*
* C++ Program to Implement the RSA Algorithm
*/
#include<iostream>
#include<math.h>
#include<string.h>
#include<stdlib.h>
using namespace std;
long int p, q, n, t, flag, e[100], d[100], temp[100], j, m[100], en[100], i;
char msg[100];
int prime(long int);
void ce();
long int cd(long int);
void encrypt();
void decrypt();
int prime(long int pr)
{
int i;
j = sqrt(pr);
for (i = 2; i <= j; i++)
{
if (pr % i == 0)
return 0;
}
return 1;
}
int main()
{
cout << "\nENTER FIRST PRIME NUMBER\n";
cin >> p;
flag = prime(p);
if (flag == 0)
{
cout << "\nWRONG INPUT\n";
exit(1);
}
cout << "\nENTER ANOTHER PRIME NUMBER\n";
cin >> q;
flag = prime(q);
if (flag == 0 || p == q)
{
cout << "\nWRONG INPUT\n";
exit(1);
}
cout << "\nENTER MESSAGE\n";
fflush(stdin);
cin >> msg;
for (i = 0; msg[i] != NULL; i++)
m[i] = msg[i];
n = p * q;
t = (p - 1) * (q - 1);
ce();
cout << "\nPOSSIBLE VALUES OF e AND d ARE\n";
for (i = 0; i < j - 1; i++)
cout << e[i] << "\t" << d[i] << "\n";
encrypt();
decrypt();
return 0;
}
void ce()
{
int k;
k = 0;
for (i = 2; i < t; i++)
{
if (t % i == 0)
continue;
flag = prime(i);
if (flag == 1 && i != p && i != q)
{
e[k] = i;
flag = cd(e[k]);
if (flag > 0)
{
d[k] = flag;
k++;
}
if (k == 99)
break;
}
}
}
long int cd(long int x)
{
long int k = 1;
while (1)
{
k = k + t;
if (k % x == 0)
return (k / x);
}
}
void encrypt()
{
long int pt, ct, key = e[0], k, len;
i = 0;
len = strlen(msg);
while (i != len)
{
pt = m[i];
pt = pt - 96;
k = 1;
for (j = 0; j < key; j++)
{
k = k * pt;
k = k % n;
}
temp[i] = k;
ct = k + 96;
en[i] = ct;
i++;
}
en[i] = -1;
cout << "\nTHE ENCRYPTED MESSAGE IS\n";
for (i = 0; en[i] != -1; i++)
printf("%c", en[i]);
}
void decrypt()
{
long int pt, ct, key = d[0], k;
i = 0;
while (en[i] != -1)
{
ct = temp[i];
k = 1;
for (j = 0; j < key; j++)
{
k = k * ct;
k = k % n;
}
pt = k + 96;
m[i] = pt;
i++;
}
m[i] = -1;
cout << "\nTHE DECRYPTED MESSAGE IS\n";
for (i = 0; m[i] != -1; i++)
printf("%c", m[i]);
}
答案 0 :(得分:0)
我不确定我的问题是否正确,但我打赌你问的是如何在ASCII和字符数字表示之间进行转换。
编码/解码与 RSA 无关。你只需使用动态范围转换。由于字母表在 ASCII 中的顺序递增,因此唯一剩下的就是将a
或A
偏移到零。
对于小写字符到数字转换尝试:
char c='m'; // c is you character m for example
int i=c-`a`; // i is output number
如果您同时使用小写和大写字母,则需要将其更改为:
char c='q'; // c is you character q for example
int i; // i is output number
if ((c>='a')&&(c<='z')) i=c-'a';
else i=c-'A';`
其中c
是您的角色,i
是输出数
对于number to char转换,请尝试:
c=i+`a`;
或大写:
c=i+`A`;