ASP.NET RSA暗号化

RSA暗号化は皆さんもよく知られていると思います.MD 5暗号化も暗号化の手段ですが、MD 5暗号化は一方向暗号化であり、復号できません.場合によっては不便なので、今日はMSDNでRSA暗号化を認識する例を探しました.
1.まずフロントエンドコード

   1:     <table style="font-family: Calibri; width: 100%">

   2:              <tr>

   3:                  <td>

   4:                      <asp:Label ID="lbwords" runat="server" Text="Enter Some Words:"></asp:Label>

   5:                  </td>

   6:                  <td colspan="3">

   7:                      <asp:TextBox ID="tbData" runat="server" Width="300px"></asp:TextBox>

   8:                  </td>

   9:              </tr>

  10:              <tr>

  11:                  <td>

  12:                      <asp:Label ID="lbEncryptData" runat="server" Text="Encrypted Data:"></asp:Label>

  13:                  </td>

  14:                  <td>

  15:                      <asp:Button ID="btnEncrypt" runat="server" Text="Encrypt it" OnClick="Encrypt_Click"

  16:                          Height="30px" Width="90px" />

  17:                      <br />

  18:                      <asp:TextBox ID="tbEncryptData" runat="server" TextMode="MultiLine" Height="200px"

  19:                          Width="400px" ReadOnly="true"></asp:TextBox>

  20:                      <br />

  21:                  </td>

  22:                  <td>

  23:                      <asp:Label ID="lbDecryptedData" runat="server" Text="Decrypted Data:"></asp:Label>

  24:                  </td>

  25:                  <td>

  26:                      <asp:Button ID="btnDecrypt" runat="server" Text="Decrypt it" OnClick="Decrypt_Click"

  27:                          Height="30px" Width="90px" />

  28:                      <br />

  29:                      <asp:TextBox ID="tbDecryptData" runat="server" TextMode="MultiLine" Height="200px"

  30:                          Width="400px" ReadOnly="true"></asp:TextBox>

  31:                      <br />

  32:                  </td>

  33:              </tr>

  34:          </table>

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.csharpcode .rem { color: #008000; }
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.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
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.csharpcode .asp { background-color: #ffff00; }
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2.バックグラウンドコード
説明:初めてのRSA暗号化に加えてC#ベースがあまり良くないため、かなり苦労しているように見えますので、コメントをたくさんつけました.暗号化と解を1つのクラスに単独で書くことができ、呼び出すのに便利ですが、暗号化やユーザー名などに使用したい場合は、設計時に十分な長さを残す必要があります.

   1:   protected void Page_Load(object sender, EventArgs e)

   2:          {

   3:              AddKeyUpEventOnTextControl();

   4:              //1.PreRender     System.Web.UI.Control     、      。

   5:              //2.  btn.Decrypt   PreRender       btnDecrypt_PreRender    （    ）

   6:              this.btnDecrypt.PreRender += new EventHandler(btnDecrypt_PreRender);

   7:              this.btnEncrypt.PreRender += new EventHandler(btnEncrypt_PreRender);

   8:          }

   9:   

  10:          private void RSAEncryption()

  11:          {

  12:   

  13:              //3.CspParameters                     (CSP)    。      。

  14:              CspParameters param = new CspParameters();

  15:              //4. KeyContainerName    System.Security.Cryptography.CspParameters        。

  16:              param.KeyContainerName = "MyKeyContainer";

  17:              //5.             (CSP)     System.Security.Cryptography.RSA                

  18:              using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(param))

  19:              {

  20:                  string plaintext = this.tbData.Text;

  21:                  byte[] plaindata = System.Text.Encoding.Default.GetBytes(plaintext);

  22:              //6.     true，    OAEP   （     Microsoft Windows XP             ）     

  23:              //System.Security.Cryptography.RSA   ；  ，    false，    PKCS#1 1.5    。

  24:                  byte[] encryptdata = rsa.Encrypt(plaindata, false);

  25:              // 7.  8                Base64               

  26:                  string encryptstring = Convert.ToBase64String(encryptdata);//      128

  27:                  this.tbEncryptData.Text = encryptstring;

  28:              }

  29:          }

  30:   

  31:          private void RSADecryption()

  32:          {

  33:              CspParameters param = new CspParameters();

  34:              param.KeyContainerName = "MyKeyContainer";

  35:              using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(param))

  36:              {

  37:                  //8.       （           Base64   ）       8         

  38:                  byte[] encryptdata = Convert.FromBase64String(this.tbEncryptData.Text);

  39:                  //9.   System.Security.Cryptography.RSA          。

  40:                  byte[] decryptdata = rsa.Decrypt(encryptdata, false);

  41:                  string plaindata = System.Text.Encoding.Default.GetString(decryptdata);

  42:                  this.tbDecryptData.Text = plaindata;

  43:              }

  44:          }

  45:   

  46:          protected void Encrypt_Click(object sender, EventArgs e)

  47:          {

  48:              RSAEncryption();

  49:          }

  50:   

  51:          protected void Decrypt_Click(object sender, EventArgs e)

  52:          {

  53:              RSADecryption();

  54:          }

  55:   

  56:          void btnDecrypt_PreRender(object sender, EventArgs e)

  57:          {

  58:              EnableDecryptButton();

  59:          }

  60:   

  61:          void btnEncrypt_PreRender(object sender, EventArgs e)

  62:          {

  63:              EnableEncryptButton();

  64:          }

  65:   

  66:          private void AddKeyUpEventOnTextControl()

  67:          {

  68:              string script = string.Format(@"function PressFn(sender) {{

  69:                                              document.getElementById('{0}').disabled = sender.value == '' ? true : false;

  70:                                              }}", btnEncrypt.ClientID);

  71:              tbData.Attributes["onkeyup"] = "PressFn(this)";

  72:              Page.ClientScript.RegisterStartupScript(this.GetType(), "DataKeyUp", script, true);

  73:          }

  74:   

  75:          /// <summary>

  76:          ///             

  77:          /// </summary>

  78:          private void EnableDecryptButton()

  79:          {

  80:              btnDecrypt.Enabled = this.tbEncryptData.Text != string.Empty ? true : false;

  81:             //              ，       if...else...

  82:          }

  83:   

  84:          /// <summary>

  85:          ///             

  86:          /// </summary>

  87:          private void EnableEncryptButton()

  88:          {

  89:              btnEncrypt.Enabled = this.tbData.Text != string.Empty ? true : false;

  90:          }

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