[C#] howto encrypth and decrypth a string value

[Jelte]

Hello everybody.

I'm bussy with learning the basics about Classes and howto use other Classes.
to practice i would like to make a program that encrypth a string and can decrypth a string value
by using: System.Security.Cryptography. but i dont know where to start :P

Could annyone provide me a simple tutorial or other explanation about how i have to handle it.

I looked at google to but all i found was prof stuff :P

thanks for your support

Jelte.

[master5001]

I think that this is probably a good place to start.

[Jelte]

mmm maybe it was smart to tell that i am Dutch and my English is not like yours. but it is understandable, isn't it?

[master5001]

Ok fair enough. My dutch is way horrible so I won't give you a hard time.
MSDN is always a good resource to start out with. Also I found this link for a tutorial (don't worry, it isn't a sarcastic link this time).

[BobS0327]

An example

[Jelte]

Thank you very much BobS0327 and master5001. it helps alot !

but know i made this by using a sample code http://www.dotnetspider.com/resource...pt-string.aspx

class Encryption
    {
        public string Crypter(string Input)
        {
            //maakt werk object TextToUni.
            System.Text.UTF8Encoding TextToUni = new System.Text.UTF8Encoding();
            //Haalt de Bytes uit TextToUni en slaat het op.
            byte [] Bytes = TextToUni.GetBytes(Input);

            //maakt werkobject aan Encoder voor het encrypten.
            System.Security.Cryptography.MD5CryptoServiceProvider Crypther = new System.Security.Cryptography.MD5CryptoServiceProvider();
            byte [] ByteHash = Crypther.ComputeHash(Bytes);

            string output = Convert.ToString(ByteHash);
            return (output);
        }

   

    }

But now I want that the returning value: output, will be showed in a textbox named tbTextNormal. i cant get that done.

thank you for your help.

Jelte.

[master5001]

tbTextNormal.Text = output, right? What exactly is the point in which it is not working?

[Jelte]

Where do I have to declare that: tbTextNormal.Text = output. Cause if I place it in Form1.cs by the botton click event is does not recognize. i can't reach it

if you know what I mean :P

[master5001]

I get what you mean. Why is it in the click event anyway? Should not you put it in the function that actually does the encryptions/decryptions?

[Jelte]

this is maybe a very dumb question but I am a beginner :P

what is return(output) doing. i shall say that it publicate the value that i want to get by using the function, to the rest of the application(outside de class) and so can be used for a textbox for example.

I hope you understand what I'm saying :P

could you show me how you show place the returned value output in a textbox ?

[master5001]

There are no such things as stupid questions, just rude replies. return(output) is giving you back a string that contains the encrypted version of the input string. So you would call it doing something like:

Example:

Encryption e;
tbTextNormal.Text  = e.Crypter("hello world");

I am no C# guru, so bear with me. I have only written one program that used exactly one module that I wrote in C#. So if my syntax is slightly out of whack, I appologize in advance.

[Jelte]

i get what you say, but still have the same problem. where do i have declare tbTextNormal.Text = output and on a way that i can reach ouput.

But nevermind i go to bed, maybe tomorrow I will awake like a C# genius

master5001 thank you very much for supporting me

Jelte.

[master5001]

No problem. Get some rest and we can work on it more tomorrow. Hopefully I wake up a C# genius. I am more of a C guy.

[BobS0327]

could you show me how you show place the returned value output in a textbox ?

using System;
using System.Text;
using System.Drawing;
using System.Windows.Forms;

public class Crypto : Form {

    Button buttonDisplayCrypto  = new Button();
    TextBox textBoxCrypto = new TextBox();
    Label labelCrypto = new Label();

    public Crypto() {
        buttonDisplayCrypto.Location = new Point(50, 100);
		buttonDisplayCrypto.Size = new Size(200, 30);
        buttonDisplayCrypto.Text = "Post Crypto Value to Text Box";

        buttonDisplayCrypto.Click += new System.EventHandler(this.buttonCalculate_Click);

        this.Controls.Add(buttonDisplayCrypto);

        textBoxCrypto.Location = new Point(10, 20);
        textBoxCrypto.Size = new Size(250, 30);
        textBoxCrypto.Text = "";
        this.Controls.Add(textBoxCrypto);

        labelCrypto.Location = new Point(10, 5);
        labelCrypto.Size = new Size(154, 15);
        labelCrypto.Text = "Crypto Value for Hello World";
        this.Controls.Add(labelCrypto);
    }
		static private string Crypter(string Input)
    {
        //maakt werk object TextToUni.
        System.Text.UTF8Encoding TextToUni = new System.Text.UTF8Encoding();
        //Haalt de Bytes uit TextToUni en slaat het op.
        byte [] Bytes = TextToUni.GetBytes(Input);

        //maakt werkobject aan Encoder voor het encrypten.
        System.Security.Cryptography.MD5CryptoServiceProvider Crypther =
				new System.Security.Cryptography.MD5CryptoServiceProvider();
        byte [] ByteHash = Crypther.ComputeHash(Bytes);
        StringBuilder sBuilder = new StringBuilder();
        for(int i = 0; i < ByteHash.Length; i++)
        {
            sBuilder.Append(ByteHash[i].ToString("x2"));
        }
        return sBuilder.ToString();
    }

    private void buttonCalculate_Click(object sender, System.EventArgs e) {
   		textBoxCrypto.Text = Crypter("Hello World");
    }

    public static void Main(string[] args) {
        Application.Run(new Crypto());
    }
}

[Jelte]

Thanks BobS032 it's working

but one little question.

Could you tell me what this is doing ?

StringBuilder sBuilder = new StringBuilder();
        for(int i = 0; i < ByteHash.Length; i++)
        {
            sBuilder.Append(ByteHash[i].ToString("x2"));
        }
        return sBuilder.ToString();

And what means x2? :P