话不多说，将加密代码附上：

​string k, c;
int len = k.size(), len1 = c.size();
for (int i = 0; i < len; i++)	k[i] = (char)(toupper(k[i]));
for (int i = 0, j = 0; i < len1; i++, j++)
{
	if (j > len - 1)	j = 0;
	if (isdigit(c[i])||!isalnum(c[i])) {
		continue;
	}
	else if (isupper(c[i]))
	{
		int a = c[i] + k[j] - 'A' + 1;
		while (a > 90)	a -= 26;
		while (a < 65)	a += 26;
		c[i] = char(a);
	}
	else if (islower(c[i]))
	{
		int a = c[i] + k[j] - 'A' + 1;
		while (a > 122)	a -= 26;
		while (a < 97)	a += 26;
		c[i] = char(a);
	}
}

因为我用的是VS2022的MFC，所以全部源码不好贴出来， 至于后来搞的安装包，已经在文章顶部展示了，这东西弄了我三四天，烦死了，不是那个报错就是这个报错，整了好久才整好接下来是解密代码：

string k, c;
int len = k.size(), len1 = c.size();
for (int i = 0; i < len; i++)	k[i] = (char)(toupper(k[i]));
for (int i = 0, j = 0; i < len1; i++, j++)
{
	if (j > len - 1)	j = 0;
	if (isdigit(c[i]) || !isalnum(c[i])) {
		continue;
	}
	else if (isupper(c[i]))
	{
		int a = c[i] - (k[j] - 'A' + 1);
		while (a < 65)	a += 26;
		while (a > 90)	a -= 26;
		c[i] = char(a);
	}
	else if (islower(c[i]))
	{
		int a = c[i] - (k[j] - 'A' + 1);
		while (a < 97)	a += 26;
		while (a > 122)	a -= 26;
		c[i] = char(a);
	}
}

 因为打代码时用的全英文，所以先出个英文版看看先，中文版很快就会有的