CryptoGraphic Message

Question

HELLO FRIENDS I m creating a CRYPTOGRAPHY WINDOWS FORM APPLICATION. 1-Calculate String Length. (ALREADY DONE) 2-Reverse the String. (ALREADY DONE) 3-Total Length of the message will be save and each character of the message will be replaced from it. (HELP REQUIRED) Example: You wrote a message  A CAT so STEP 1: calculate Length : 5 STEP 2: reverse : TAC A STEP 3 : String length is added: so 5 is added to each corresponding character A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Therefore A is at 1  when 5 is added it will become F which is 6 C is at 3 when 5 is added it will become H which is 8 A is again replaced with F T is at 20 when 5 is added it will become Y which is 25 Therefore A message A CAT will become  F HFY So far i done that: public partial class Form1 : Form { public Form1() { InitializeComponent(); } public string UIT_CRYPTOGRAPHY() { string userString = richTextBox1.Text; char[] textArray = userString.ToCharArray(); int stringLength = userString.Length; Array.Reverse(textArray); label1.Text = new string(textArray); return label1.Text; } private void button3_Click(object sender EventArgs e) { /* string[] stringArray = {abcdefghijklmnopqrstuvwxyz };*/ string ReverseString = UIT_CRYPTOGRAPHY(); label1.Text = ReverseString; } PLEASE HELP ME THANKS IN ADVANCE.

prince shils · Answer

ThankYou Sam Hobbs I did it.

prince shils · Answer

Oh Brilliant!! Yes I did ThankYou Vulpes.

Sam Hobbs · Answer

I am not sure what you need. I hope the following is headed in the correct direction. This does not check what character it is and it does not do wrap-around as Vulpes is doing. I am not sure if you want to limit this to specific characters. int n = richTextBox1.Text.Length; StringBuilder sb = new StringBuilder (n); for ( int i = n - 1; i >= 0; --i) sb.Append(( char )(richTextBox1.Text[i] + n)); label1.Text = sb.ToString();

Vulpes · Answer

You have two problems there: 1. You need to wrap around if k is less than 65 rather than if k is more than 90. 2. You need to reverse the string after the above manipulation rather than before it. You can do all this in the Decode button Click handler alone: private void btnDecode_Click(object sender EventArgs e) { string DecodeString = label1.Text.ToUpper(); int len = DecodeString.Length; char[] decrypted = new char[len]; // create an array to hold the decrypted characters for (int i = 0; i { int j = DecodeString[i]; // char is implicitly convertible to int so A -> 65 B -> 66 etc. if (j >= 65 && j { int k = DecodeString[i] - len; // subtract len if (k decrypted[i] = (char)k; // convert back to a character } else { decrypted[i] = DecodeString[i]; // leave unchanged } } // reverse the array Array.Reverse(decrypted); label2.Text = new string(decrypted); // create new string and assign to label }

prince shils · Answer

Plz Vulpes check my code when i want to back my original message some character are not correctly decode. For example: when i decode WONDERFULL result returns =ONDE8F;LL which is wrong. here is a code: //DECODE METHOD public string CRYPTOGRAPHY_REVERSE() { label1.Text = label1.Text.ToUpper(); // convert to upper case string userString = label1.Text; char[] decodeArray = userString.ToCharArray(); int stringLength = userString.Length; Array.Reverse(decodeArray); label2.Text = new string(decodeArray); return label2.Text; } //DECODE BUTTON CODE string DecodeString = CRYPTOGRAPHY_REVERSE(); int len = DecodeString.Length; char[] encrypted = new char[len]; // create an array to hold the encrypted characters for (int i = 0; i { int j = DecodeString[i]; // char is implicitly convertible to int so A -> 65 B -> 66 etc. if (j >= 65 && j { int k = DecodeString[i] - len; // add 5 if (k > 90) k += 26; // wrap round if more than 90 encrypted[i] = (char)k; // convert back to a character } else { encrypted[i] = DecodeString[i]; // leave unchanged } } label2.Text = new string(encrypted); // create new string and assign to label //THANKYOU

prince shils · Answer

You are great! Thank You so much.

Vulpes · Answer

I suggest that you convert the message to all upper case say to make it easier to encode. You can then use the fact that the letters A to Z have ASCII values of 65 to 90 inclusive to add 5 to them and convert back to a character. The last 5 letters V W X Y and Z will need to 'wrap round' so they are mapped to A B C D and E respectively. Here's some revised code: public string UIT_CRYPTOGRAPHY() { richTextBox1.Text = richTextBox1.Text.ToUpper(); // convert to upper case string userString = richTextBox1.Text; char[] textArray = userString.ToCharArray(); int stringLength = userString.Length; Array.Reverse(textArray); label1.Text = new string(textArray); return label1.Text; } private void button5_Click(object sender EventArgs e) { string ReverseString = UIT_CRYPTOGRAPHY(); int len = ReverseString.Length; char[] encrypted = new char[len]; // create an array to hold the encrypted characters for(int i = 0 ; i { int j = ReverseString[i]; // char is implicitly convertible to int so A -> 65 B -> 66 etc. if (j >= 65 && j { int k = ReverseString[i] + 5; // add 5 if (k > 90) k -= 26; // wrap round if more than 90 encrypted[i] = (char)k; // convert back to a character } else { encrypted[i] = ReverseString[i]; // leave unchanged } } label1.Text = new string(encrypted); // create new string and assign to label }