单表加密.cpp

单表加密的加密方法一般是代替或置换,是本人密码学所做课题,内赋两个版本.

#include "stdio.h"
#define MAXSIZE 100
void main()
{
 	char mingwen[26];
	char key[26];
	char miwen[26];
	char mBuf[MAXSIZE];
	int j=0,c,i,k = 'a';
	for(i = 0; i < 26; i++)
	{
		mingwen[i] = k;
		k++;
	}
	for (i=0; i < 26; i++)
	{
	 printf("%c", mingwen[i]);
	}
	
	printf("\n");


	i = j = 0;
	while ((c = getchar()) != '\n')
	{
		while (i != (j+1))
		{
		
			if (c != key[i])
				++i;
			else
				c = 0;
		}
		if (c != 0)
		{
		key[j] = c;
		j++;
		i = 0;
		}
	}


	
/*	j = 0;
	i = 1;
	while ((c = getchar()) != '\n')
	{
		++i;
		for (; j <= i-1; )
		{
			if(c == key[j])
			;
			else
			{
				key[j] = c;
				j++;
			}
		}
		
	}
	*/
	for (i =0; i < j; i++)
	{
		miwen[i] = key[i];
	}

/*建立原始秘文 ver 1.0*/
  /*  int n = j, w;
	i = 0;
	while (i < 26)
	{
    for( w = 0; w < j; )
	{
		if(mingwen[i] != miwen[w])
			w++;
		else
			++i;
	} 
		miwen[n] = mingwen[i];
		i++;
		w=0;
		n++;
	}
*/

/*建立原始秘文 ver 2.0*/
	int w, 	n = j;

	i = 0;
    for( w = 0; w < j && i < 26; )
	{
		if(mingwen[i] != miwen[w])
			w++;
		if (mingwen[i] == miwen[w])
			++i;
	    else if (w == j)
		{
		miwen[n] = mingwen[i];
		i++;
		w=0;
		n++;
		}
	}
	
	n = 0;
	while ((c = getchar()) != '\n')	
	{
		for (i = 0; c != mingwen[i]; i++)
		;

		mBuf[n] = miwen[i];
		n++;
	}
	for(i = 0; i < n; i++)
	printf("%c", mBuf[i]);
	printf("\n");
}