[英]substitution cipher case sensitive using c#
我想使加密方法可以接受純文本變量(例如“ Hello World”)中的大寫和小寫字母,它僅接受小寫字母,請幫助我,我想使用僅小寫字母作為輸入,請使其工作正常,請幫助我
using System;
class SubstitutionCipher
{
static void Main()
{
string key = "jfkgotmyvhspcandxlrwebquiz";
string plainText = "the quick brown fox jumps over the lazy dog";
string cipherText = Encrypt(plainText, key);
string decryptedText = Decrypt(cipherText, key);
Console.WriteLine("Plain : {0}", plainText);
Console.WriteLine("Encrypted : {0}", cipherText);
Console.WriteLine("Decrypted : {0}", plainText);
Console.ReadKey();
}
//encryption method
static string Encrypt(string plainText, string key)
{
char[] chars = new char[plainText.Length];
for(int i = 0; i < plainText.Length; i++)
{
if (plainText[i] == ' ')
{
chars[i] = ' ';
}
else
{
int j = plainText[i] - 97;
chars[i] = key[j];
}
}
return new string(chars);
}
//decryption method
static string Decrypt(string cipherText, string key)
{
char[] chars = new char[cipherText.Length];
for(int i = 0; i < cipherText.Length; i++)
{
if (cipherText[i] == ' ')
{
chars[i] = ' ';
}
else
{
int j = key.IndexOf(cipherText[i]) - 97;
chars[i] = (char)j;
}
}
return new string(chars);
}
}
您要減去“ a”,這僅適用於小寫字符。 您應該檢查它是大寫還是小寫,然后分別減去A或a。 另外,您可以直接使用'a'或'A'來獲得與字符等效的int
。
我的意思是將此用於您的else
Decrypt和Encrypt語句:
static string Encrypt(string plainText, string key)
{
char[] chars = new char[plainText.Length];
for (int i = 0; i < plainText.Length; i++)
{
if (plainText[i] == ' ')
{
chars[i] = ' ';
}
else if (Char.IsUpper(plainText[i]))
{
int j = plainText[i] - 'A';
chars[i] = key[j];
}
else
{
int j = plainText[i] - 'a';
chars[i] = key[j];
}
}
return new string(chars);
static string Decrypt(string cipherText, string key)
{
char[] chars = new char[cipherText.Length];
for (int i = 0; i < cipherText.Length; i++)
{
if (cipherText[i] == ' ')
{
chars[i] = ' ';
}
else if (Char.IsUpper(cipherText[i]))
{
int j = key.IndexOf(cipherText[i]) - 'A';
chars[i] = (char)j;
}
else
{
int j = key.IndexOf(cipherText[i]) - 'a';
chars[i] = (char)j;
}
}
return new string(chars);
}
或分別為加密和解密的簡短版本:
else
{
int j = Char.IsUpper(plainText[i]) ? plainText[i] - 'A' : plainText[i] - 'a';
chars[i] = key[j];
}
else
{
int j = Char.IsUpper(cipherText[i]) ? key.IndexOf(cipherText[i]) - 'A' : key.IndexOf(cipherText[i]) - 'a';
chars[i] = (char)j;
}
編輯:
好的,我認為該算法已經完成,並且我已經修復了可能導致異常的部分。 但是,您是:
a)不考慮哪個字母大寫,並且b)沒有有效的解密器。 (我認為這是可行的,但隨后您的主要方法將純文本結果作為解密的消息)。
要修復您的解密器,您需要在加密器上添加一種存儲大寫字母的方法。 您可以對此進行更復雜的介紹,但是現在,我們僅將其加密為密文中的大寫字母。
static string Encrypt(string plainText, string key)
{
char[] chars = new char[plainText.Length];
for (int i = 0; i < plainText.Length; i++)
{
if (plainText[i] == ' ')
{
chars[i] = ' ';
}
else
{
int j = Char.IsUpper(plainText[i]) ? plainText[i] - 'A' : plainText[i] - 'a';
chars[i] = Char.IsUpper(plainText[i]) ? Char.ToUpper(key[j]) : key[j];
}
}
return new string(chars);
要解密,您應該在密鑰上找到它為小寫字符,但輸出為大寫字符。
static string Decrypt(string cipherText, string key)
{
char[] chars = new char[cipherText.Length];
for (int i = 0; i < cipherText.Length; i++)
{
if (cipherText[i] == ' ')
{
chars[i] = ' ';
}
else
{
int j = Char.IsUpper(cipherText[i]) ? key.IndexOf(Char.ToLower((char)cipherText[i])) + 'a' : key.IndexOf(cipherText[i]) + 'a';
chars[i] = Char.IsUpper(cipherText[i]) ? Char.ToUpper((char)j) : (char)j;
}
}
return new string(chars);
}
這是一個有趣的問題,尤其是在一般情況下 。 所以我們有
a
, j
) 為了提高效率,我們將Encryptor
\\ Decryptor
設計為Dictionary<Char, Char>
,為了做到這一點,我們應該對密鑰中的字符進行排序並使其對應。 例如
key = "jfkgo"
sorted key = "fgjko"
對將是
{j, f} // when encrypting "j" becomes "f", on decryption "f" turns into "j"
{f, g}
{k, j}
{g, k}
{o, o}
從左到右讀取時,我們有一個加密器 ; 從右到左讀取時,有一個解密器 :
private static Dictionary<Char, Char> Encryptor(String key) {
Char[] data = key.ToArray();
Char[] sorted = data.OrderBy(c => c).ToArray();
return data
.Zip(sorted, (plain, encrypted) => new {
Plain = plain,
Encrypted = encrypted
})
.ToDictionary(item => item.Plain, item => item.Encrypted);
}
// Note, that Decryptor is the same as Encryptor by for the last line
private static Dictionary<Char, Char> Decryptor(String key) {
Char[] data = key.ToArray();
Char[] sorted = data.OrderBy(c => c).ToArray();
return data
.Zip(sorted, (plain, encrypted) => new {
Plain = plain,
Encrypted = encrypted
})
.ToDictionary(item => item.Encrypted, item => item.Plain);
}
現在,很容易實現Encrypt和Decrypt方法
private static String Encrypt(String source, String key) {
var dict = Encryptor(key);
StringBuilder Sb = new StringBuilder(source.Length);
Char sub;
foreach (var ch in source)
if (dict.TryGetValue(ch, out sub))
Sb.Append(sub);
else
Sb.Append(ch);
return Sb.ToString();
}
// Note, that Decryptor is the same as Encryptor by for the first line
private static String Decrypt(String source, String key) {
var dict = Decryptor(key);
StringBuilder Sb = new StringBuilder(source.Length);
Char sub;
foreach (var ch in source)
if (dict.TryGetValue(ch, out sub))
Sb.Append(sub);
else
Sb.Append(ch);
return Sb.ToString();
}
小測試
// For test, let capital letters mmimic the small ones
string key = "jfkgotmyvhspcandxlrwebquiz" + "jfkgotmyvhspcandxlrwebquiz".ToUpper();
string plainText = "The Quick Brown Fox Jumps Over The Lazy Dog!";
string cipherText = Encrypt(plainText, key);
string decryptedText = Decrypt(cipherText, key);
Console.WriteLine("Plain : {0}", plainText);
Console.WriteLine("Encrypted : {0}", cipherText);
Console.WriteLine("Decrypted : {0}", plainText);
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.