1

这是我解密自动密钥 vigenere 密码算法的代码

string cipherText = "zicvtwqngkzeiigasxstslvvwla";
string key = "deceptive";

key = key.ToLower();
cipherText = cipherText.ToLower();

int klength = key.Length;
int kslength = (int)(cipherText.Length - key.Length);

string pl = string.Empty;
char[] newpl = new char[cipherText.Length];
int a = Convert.ToInt32('a');
for (int i = 0; i < cipherText.Length - kslength; i++)
{
    int c = Convert.ToInt32(cipherText[i]) - a;
    if (c< 0) c += 26;
    int k = Convert.ToInt32(key[i]) - a;
    if (k < 0) k += 26;
    int p = (c - k);
    p %= 26;
    if (p < 0) p += 26;
    p += a;
    char temp = Convert.ToChar(p);
    newpl[i] = temp;

}

char[] NewKey = new char[cipherText.Length];
char[] ciphertext = new char[cipherText.Length];
char[] chars = new char[cipherText.Length];
int count =0;
for (int i = 0; i < key.Length; i++)
{
    NewKey[i] = key[i];
    count++;
}
int j = 0;
for (int i = count; i < cipherText.Length; i++)
{
    NewKey[i] = newpl[j];
    j++;
}

Console.WriteLine(NewKey);

for (int i = klength; i < cipherText.Length; i++)
{
    int c = Convert.ToInt32(cipherText[i]) - a;
    int k = Convert.ToInt32(NewKey[i]) - a;
    int p = (c - k);
    p %= 26;
    if (p < 0) p += 26;
    p += a;

    char temp = Convert.ToChar(p);
    newpl[i] = temp;
}
pl = new string(newpl);
Console.WriteLine(pl);

它给了我输出：

欺骗性磨损光盘

穿着发现savlmleoopet

而正确的输出应该是：

欺骗性服装ediscoveredsav

穿上发现自救

输出的第一行是指自动生成的密钥

第二行指的是解密后的文本。

4

1 回答 1

1

您的代码中几乎没有错误：

1）看这一行：

for (int i = 0; i < cipherText.Length - kslength; i++)

kslength = cipherText.Length - key.Length所以你的代码是

for (int i = 0; i < key.Length; i++)

密钥长度小于文本长度，因此您过早完成解密。

2)

char temp = Convert.ToChar(p);
newpl[i] = temp;

您解密了符号，但使用自动密钥解密，您应该将解密的符号添加到您的密钥中。

3)

for (int i = 0; i < key.Length; i++)

应该NewKey.Length改为，因为key在修复 #2 后我们真正需要的时间更长。

固定代码：

string cipherText = "zicvtwqngkzeiigasxstslvvwla";
string key = "deceptive";

key = key.ToLower();
cipherText = cipherText.ToLower();

int klength = key.Length;

string pl = string.Empty;
char[] newpl = new char[cipherText.Length];
int a = Convert.ToInt32('a');
for (int i = 0; i < cipherText.Length; i++)
{
    int c = Convert.ToInt32(cipherText[i]) - a;
    if (c < 0) c += 26;
    int k = Convert.ToInt32(key[i]) - a;
    if (k < 0) k += 26;
    int p = (c - k);
    p %= 26;
    if (p < 0) p += 26;
    p += a;
    char temp = Convert.ToChar(p);
    key += temp;
    newpl[i] = temp;

}

char[] NewKey = new char[cipherText.Length];
int count = 0;
for (int i = 0; i < NewKey.Length; i++)
{
    NewKey[i] = key[i];
    count++;
}
int j = 0;
for (int i = count; i < cipherText.Length; i++)
{
    NewKey[i] = newpl[j];
    j++;
}

Console.WriteLine(NewKey);

for (int i = klength; i < cipherText.Length; i++)
{
    int c = Convert.ToInt32(cipherText[i]) - a;
    int k = Convert.ToInt32(NewKey[i]) - a;
    int p = (c - k);
    p %= 26;
    if (p < 0) p += 26;
    p += a;

    char temp = Convert.ToChar(p);
    newpl[i] = temp;
}
pl = new string(newpl);
Console.WriteLine(pl);

输出：

欺骗性服装ediscoveredsav

穿上发现自救

于 2019-03-13T21:14:33.663 回答