Криптография и защита на C#

В этом примере мы зашифруем сообщение с помощью RSA, и проверим его на соответствие вводимого сообщения, путем сверки цифровой подписи.

Для этого создадим вспомогательные классы для работы:

using System; 
using System.Security.Cryptography; 
using System.Text; 

public class MD5HashHelper 
{ 

	public byte[] GetHash(string message) 
	{ 
		byte[] data; 
		data = UTF8Encoding.ASCII.GetBytes(message); 
		MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider(); 
		return md5.ComputeHash(data, 0, data.Length); 
	} 

	public bool VerifyHash(string message, byte[] hash) 
	{ 
		byte[] data; 
		data = UTF8Encoding.ASCII.GetBytes(message); 
		MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider(); 
		byte[] hashTemp = md5.ComputeHash(data, 0, data.Length); 

		for (Int32 counter = 0; counter <= hash.Length - 1; counter += 1) 
		{
			if (hash[counter] != hashTemp[counter]) 
			{ 
				return false; 
			} 
		} 
		return true; 
	} 
}

public class DigitalSignatureHelper 
{ 
	private RSAParameters m_public; 

	public byte[] CreateSignature(byte[] hash) 
	{ 
		RSACryptoServiceProvider RSA = new RSACryptoServiceProvider(); 
		RSAPKCS1SignatureFormatter RSAFormatter = new RSAPKCS1SignatureFormatter(RSA); 
		RSAFormatter.SetHashAlgorithm("MD5"); 
		m_public = RSA.ExportParameters(false); 
		return RSAFormatter.CreateSignature(hash); 
	} 

	public bool VerifySignature(byte[] hash, byte[] signedhash) 
	{ 
		RSACryptoServiceProvider RSA = new RSACryptoServiceProvider(); 
		RSAParameters RSAKeyInfo = new RSAParameters(); 
		RSAKeyInfo.Modulus = m_public.Modulus; 
		RSAKeyInfo.Exponent = m_public.Exponent; 
		RSA.ImportParameters(RSAKeyInfo); 
		RSAPKCS1SignatureDeformatter RSADeformatter = new RSAPKCS1SignatureDeformatter(RSA); 
		RSADeformatter.SetHashAlgorithm("MD5"); 
		return RSADeformatter.VerifySignature(hash, signedhash); 
	} 
}

using System;

using System.Security.Cryptography;

using System.Text;

public class MD5HashHelper

{

public byte[] GetHash(string message)

{

byte[] data;

data = UTF8Encoding.ASCII.GetBytes(message);

MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();

return md5.ComputeHash(data, 0, data.Length);

}

public bool VerifyHash(string message, byte[] hash)

{

byte[] data;

data = UTF8Encoding.ASCII.GetBytes(message);

MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();

byte[] hashTemp = md5.ComputeHash(data, 0, data.Length);

for (Int32 counter = 0; counter <= hash.Length - 1; counter += 1)

{

if (hash[counter] != hashTemp[counter])

{

return false;

}

return true;

}

public class DigitalSignatureHelper

{

private RSAParameters m_public;

public byte[] CreateSignature(byte[] hash)

{

RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();

RSAPKCS1SignatureFormatter RSAFormatter = new RSAPKCS1SignatureFormatter(RSA);

RSAFormatter.SetHashAlgorithm("MD5");

m_public = RSA.ExportParameters(false);

return RSAFormatter.CreateSignature(hash);

}

public bool VerifySignature(byte[] hash, byte[] signedhash)

{

RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();

RSAParameters RSAKeyInfo = new RSAParameters();

RSAKeyInfo.Modulus = m_public.Modulus;

RSAKeyInfo.Exponent = m_public.Exponent;

RSA.ImportParameters(RSAKeyInfo);

RSAPKCS1SignatureDeformatter RSADeformatter = new RSAPKCS1SignatureDeformatter(RSA);

RSADeformatter.SetHashAlgorithm("MD5");

return RSADeformatter.VerifySignature(hash, signedhash);

}

И код формы:

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace DigitalSignature_Example
{
	/// <summary>
	/// Summary description for Form1.
	/// </summary>
	public class Form1 : System.Windows.Forms.Form
	{
		internal System.Windows.Forms.Button Button2;
		internal System.Windows.Forms.Button Button1;
		private System.Windows.Forms.TextBox textBox1;
		private System.Windows.Forms.TextBox textBox2;
		private System.Windows.Forms.Label label1;
		private System.Windows.Forms.Label label2;
		/// <summary>
		/// Required designer variable.
		/// </summary>
		private System.ComponentModel.Container components = null;

		public Form1()
		{
			//
			// Required for Windows Form Designer support
			//
			InitializeComponent();

			//
			// TODO: Add any constructor code after InitializeComponent call
			//
		}

		/// <summary>
		/// Clean up any resources being used.
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if (components != null) 
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region Windows Form Designer generated code
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{
			this.Button2 = new System.Windows.Forms.Button();
			this.Button1 = new System.Windows.Forms.Button();
			this.textBox1 = new System.Windows.Forms.TextBox();
			this.textBox2 = new System.Windows.Forms.TextBox();
			this.label1 = new System.Windows.Forms.Label();
			this.label2 = new System.Windows.Forms.Label();
			this.SuspendLayout();
			// 
			// Button2
			// 
			this.Button2.Location = new System.Drawing.Point(224, 24);
			this.Button2.Name = "Button2";
			this.Button2.Size = new System.Drawing.Size(112, 23);
			this.Button2.TabIndex = 5;
			this.Button2.Text = "Generate Signature";
			this.Button2.Click += new System.EventHandler(this.Button2_Click);
			// 
			// Button1
			// 
			this.Button1.Location = new System.Drawing.Point(224, 64);
			this.Button1.Name = "Button1";
			this.Button1.Size = new System.Drawing.Size(112, 23);
			this.Button1.TabIndex = 4;
			this.Button1.Text = "Verify Signature";
			this.Button1.Click += new System.EventHandler(this.Button1_Click);
			// 
			// textBox1
			// 
			this.textBox1.Location = new System.Drawing.Point(120, 24);
			this.textBox1.Name = "textBox1";
			this.textBox1.Size = new System.Drawing.Size(96, 20);
			this.textBox1.TabIndex = 6;
			this.textBox1.Text = "My Signature";
			// 
			// textBox2
			// 
			this.textBox2.Location = new System.Drawing.Point(120, 64);
			this.textBox2.Name = "textBox2";
			this.textBox2.Size = new System.Drawing.Size(96, 20);
			this.textBox2.TabIndex = 7;
			this.textBox2.Text = "My Signature";
			// 
			// label1
			// 
			this.label1.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(178)));
			this.label1.Location = new System.Drawing.Point(8, 24);
			this.label1.Name = "label1";
			this.label1.TabIndex = 8;
			this.label1.Text = "Set Signature";
			// 
			// label2
			// 
			this.label2.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(178)));
			this.label2.Location = new System.Drawing.Point(8, 64);
			this.label2.Name = "label2";
			this.label2.TabIndex = 9;
			this.label2.Text = "Verify Signature";
			// 
			// Form1
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.ClientSize = new System.Drawing.Size(344, 110);
			this.Controls.Add(this.label2);
			this.Controls.Add(this.label1);
			this.Controls.Add(this.textBox2);
			this.Controls.Add(this.textBox1);
			this.Controls.Add(this.Button2);
			this.Controls.Add(this.Button1);
			this.MaximizeBox = false;
			this.Name = "Form1";
			this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
			this.Text = "Digital Signature - By Fadi Abdel-qader";
			this.ResumeLayout(false);

		}
		#endregion

		/// <summary>
		/// The main entry point for the application.
		/// </summary>
		[STAThread]
		static void Main() 
		{
			Application.Run(new Form1());
		}

		DigitalSignatureHelper ds = new DigitalSignatureHelper(); 
		byte[] hash1; 
		byte[] hash2; 
		byte[] signedhash;

		private void Button2_Click(object sender, System.EventArgs e)
		{
			try 
			{
				MD5HashHelper md5 = new MD5HashHelper(); 
				hash1 = md5.GetHash(textBox1.Text); 
				signedhash = ds.CreateSignature(hash1); 
				MessageBox.Show("Подпись создана успешно!");
			}
			catch(Exception ex){MessageBox.Show(ex.Message);}
			}

		private void Button1_Click(object sender, System.EventArgs e)
		{
			try
			{
				MD5HashHelper md5 = new MD5HashHelper();
				hash2 = md5.GetHash(textBox2.Text); 

				if (ds.VerifySignature(hash2, signedhash)) 
				{ 
					MessageBox.Show("Подписи проверены Успешно!"); 
				} 
				else 
				{ 
					MessageBox.Show("Не удалось проверить подписи!"); 
				}
			}
			catch(Exception ex){MessageBox.Show(ex.Message);}
		}
	}
}

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using System;

using System.Drawing;

using System.Collections;

using System.ComponentModel;

using System.Windows.Forms;

using System.Data;

namespace DigitalSignature_Example

{

/// <summary>

/// Summary description for Form1.

/// </summary>

public class Form1 : System.Windows.Forms.Form

{

internal System.Windows.Forms.Button Button2;

internal System.Windows.Forms.Button Button1;

private System.Windows.Forms.TextBox textBox1;

private System.Windows.Forms.TextBox textBox2;

private System.Windows.Forms.Label label1;

private System.Windows.Forms.Label label2;

/// <summary>

/// Required designer variable.

/// </summary>

private System.ComponentModel.Container components = null;

public Form1()

{

// Required for Windows Form Designer support

InitializeComponent();

// TODO: Add any constructor code after InitializeComponent call

}

/// <summary>

/// Clean up any resources being used.

/// </summary>

protected override void Dispose( bool disposing )

{

if( disposing )

{

if (components != null)

{

components.Dispose();

}

base.Dispose( disposing );

}

#region Windows Form Designer generated code

/// <summary>

/// Required method for Designer support - do not modify

/// the contents of this method with the code editor.

/// </summary>

private void InitializeComponent()

{

this.Button2 = new System.Windows.Forms.Button();

this.Button1 = new System.Windows.Forms.Button();

this.textBox1 = new System.Windows.Forms.TextBox();

this.textBox2 = new System.Windows.Forms.TextBox();

this.label1 = new System.Windows.Forms.Label();

this.label2 = new System.Windows.Forms.Label();

this.SuspendLayout();

// Button2

this.Button2.Location = new System.Drawing.Point(224, 24);

this.Button2.Name = "Button2";

this.Button2.Size = new System.Drawing.Size(112, 23);

this.Button2.TabIndex = 5;

this.Button2.Text = "Generate Signature";

this.Button2.Click += new System.EventHandler(this.Button2_Click);

// Button1

this.Button1.Location = new System.Drawing.Point(224, 64);

this.Button1.Name = "Button1";

this.Button1.Size = new System.Drawing.Size(112, 23);

this.Button1.TabIndex = 4;

this.Button1.Text = "Verify Signature";

this.Button1.Click += new System.EventHandler(this.Button1_Click);

// textBox1

this.textBox1.Location = new System.Drawing.Point(120, 24);

this.textBox1.Name = "textBox1";

this.textBox1.Size = new System.Drawing.Size(96, 20);

this.textBox1.TabIndex = 6;

this.textBox1.Text = "My Signature";

// textBox2

this.textBox2.Location = new System.Drawing.Point(120, 64);

this.textBox2.Name = "textBox2";

this.textBox2.Size = new System.Drawing.Size(96, 20);

this.textBox2.TabIndex = 7;

this.textBox2.Text = "My Signature";

// label1

this.label1.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(178)));

this.label1.Location = new System.Drawing.Point(8, 24);

this.label1.Name = "label1";

this.label1.TabIndex = 8;

this.label1.Text = "Set Signature";

// label2

this.label2.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(178)));

this.label2.Location = new System.Drawing.Point(8, 64);

this.label2.Name = "label2";

this.label2.TabIndex = 9;

this.label2.Text = "Verify Signature";

// Form1

this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);

this.ClientSize = new System.Drawing.Size(344, 110);

this.Controls.Add(this.label2);

this.Controls.Add(this.label1);

this.Controls.Add(this.textBox2);

this.Controls.Add(this.textBox1);

this.Controls.Add(this.Button2);

this.Controls.Add(this.Button1);

this.MaximizeBox = false;

this.Name = "Form1";

this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;

this.Text = "Digital Signature - By Fadi Abdel-qader";

this.ResumeLayout(false);

}

#endregion

/// <summary>

/// The main entry point for the application.

/// </summary>

[STAThread]

static void Main()

{

Application.Run(new Form1());

}

DigitalSignatureHelper ds = new DigitalSignatureHelper();

byte[] hash1;

byte[] hash2;

byte[] signedhash;

private void Button2_Click(object sender, System.EventArgs e)

{

try

{

MD5HashHelper md5 = new MD5HashHelper();

hash1 = md5.GetHash(textBox1.Text);

signedhash = ds.CreateSignature(hash1);

MessageBox.Show("Подпись создана успешно!");

}

catch(Exception ex){MessageBox.Show(ex.Message);}

}

private void Button1_Click(object sender, System.EventArgs e)

{

try

{

MD5HashHelper md5 = new MD5HashHelper();

hash2 = md5.GetHash(textBox2.Text);

if (ds.VerifySignature(hash2, signedhash))

{

MessageBox.Show("Подписи проверены Успешно!");

}

else

{

MessageBox.Show("Не удалось проверить подписи!");

}

catch(Exception ex){MessageBox.Show(ex.Message);}

}

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