Length of the data to decrypt is invalid

B

Bishoy George

I made a class based on RijndaelManaged class.
I tied to separate the encrypting and decrypting processes.

I now have the follwing resistant error:
Length of the data to decrypt is invalid
Line 70: cs.Read(fromEncrypted, 0, fromEncrypted.Length);

I need a fix please.....

The Code:
--------------------------------------------------

using System;

using System.Data;

using System.Configuration;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.IO;

using System.Text;

using System.Security.Cryptography;

public class MyEncryption : System.Web.UI.Page

{

public MyEncryption()

{

}

public static string Encrypt(string original)

{

byte[] encrypted;

byte[] toEncrypt;

byte[] key;

byte[] IV;

ASCIIEncoding textConverter = new ASCIIEncoding();

toEncrypt = textConverter.GetBytes(original);

RijndaelManaged myRijndael = new RijndaelManaged();

myRijndael.GenerateKey();

myRijndael.GenerateIV();

key = myRijndael.Key;

IV = myRijndael.IV;

MyEncryption me = new MyEncryption();

me.SetVariables(key, IV);

MemoryStream ms = new MemoryStream();

ICryptoTransform encryptor = myRijndael.CreateEncryptor(key,IV);

CryptoStream cs = new CryptoStream(ms, encryptor,CryptoStreamMode.Write);

cs.Write(toEncrypt, 0, toEncrypt.Length);

cs.FlushFinalBlock();

encrypted = ms.ToArray();

string final = Convert.ToBase64String(encrypted);

return final;

}

public static string Decrypt(string encryptedString)

{

byte[] key;

byte[] IV;

byte[] encrypted;

byte[] fromEncrypted;

MyEncryption me = new MyEncryption();

me.GetVariables(out key, out IV);

ASCIIEncoding textConverter = new ASCIIEncoding();

encrypted = textConverter.GetBytes(encryptedString);

fromEncrypted = new byte[encrypted.Length];

MemoryStream ms = new MemoryStream(encrypted);

RijndaelManaged myRijndael = new RijndaelManaged();

ICryptoTransform decryptor = myRijndael.CreateDecryptor(key,IV);

CryptoStream cs = new CryptoStream(ms, decryptor,CryptoStreamMode.Read);

cs.Read(fromEncrypted, 0, fromEncrypted.Length);

string decryptedString = Convert.ToBase64String(fromEncrypted);

return decryptedString;

}

private void SetVariables(byte[] key, byte[] IV)

{

Session["key"] = key;

Session["IV"] = IV;

}

private void GetVariables(out byte[] key, out byte[] IV)

{

key = (byte[])Session["key"];

IV = (byte[])Session["IV"];

}

}
 
J

Jim Andersen

I now have the follwing resistant error:
Length of the data to decrypt is invalid
Line 70: cs.Read(fromEncrypted, 0, fromEncrypted.Length);
Click to expand...

I can't see how you call those 2 functions, but I had something of the same,
I encrypted a string, stored it in a database table, and later decrypted it.
Had the same problem U did. Until I found out the field in the table wasn't
long enough to hold all of the encrypted string. So I didn't pass the
encrypted string to my decrypt fundtion. But a cut-off version of the
string.

/jim
 
B

Bishoy George

Dear Jim,
In my case it is different, I just store the encrypted string in a Session
Variable and get it again from that Session Variable.

You said: "I can't see how you call those 2 functions"
My Answer is: by a web page:
- its url: http://testarea.nagyresearch.com/Test.aspx
- its code:

-------------------------- 1- Server html code ------------------------

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Test.aspx.cs"
Inherits="NagyResearch.Test" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Test Page</title>
</head>
<body onload="popup();">
<form id="form1" runat="server">
<div>
<asp:Label ID="Label1" runat="server" Text="Test To
Encrypt:"></asp:Label>
<asp:TextBox ID="txtToEncrypt" runat="server"
Width="274px"></asp:TextBox>
<br />
<br />
<asp:Button ID="btnEncrypt" runat="server"
OnClick="btnEncrypt_Click" Text="Encrypt!"
Width="157px" /><br />
<br />
<asp:Label ID="lblResult" runat="server" Height="46px"
Width="774px"></asp:Label><br />
<br />
<asp:Button ID="btnDecrypt" runat="server"
OnClick="btnDecrypt_Click" Text="Decrypt!"
Width="158px" /><br />
<br />
&nbsp;
<asp:TextBox ID="txtDecryptedResult" runat="server" Height="53px"
Width="770px"></asp:TextBox></div>
</form>
</body>
</html>


--------------------------------- 2- Code
Behind -----------------------------------

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text;

namespace NagyResearch
{
public partial class Test : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
protected void btnEncrypt_Click(object sender, EventArgs e)
{
lblResult.Text = MyEncryption.Encrypt(txtToEncrypt.Text);
}
protected void btnDecrypt_Click(object sender, EventArgs e)
{
txtDecryptedResult.Text = MyEncryption.Decrypt(lblResult.Text);
}
}
}


--------------------------------------------------- Class
Code ------------------------------------------------

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Text;
using System.Security.Cryptography;

namespace NagyResearch
{
/// <summary>
/// Summary description for MyEncryption
/// </summary>
public class MyEncryption : System.Web.UI.Page
{
public MyEncryption()
{
//
// TODO: Add constructor logic here
//
}

public static string Encrypt(string original)
{
byte[] encrypted; // here we put encrypted array of bytes
byte[] toEncrypt; // here we put original array of bytes to
encrypt them // also called buffer
byte[] key; // Secret Key for encryption
byte[] IV; // Initialization Vector

// Convert a string to a byte array /////// VERY IMPORTANT
///////
ASCIIEncoding textConverter = new ASCIIEncoding();
toEncrypt = textConverter.GetBytes(original);

// Create a new key and initialization vector
RijndaelManaged myRijndael = new RijndaelManaged();
myRijndael.GenerateKey();
myRijndael.GenerateIV();
// Get the key and IV
key = myRijndael.Key;
IV = myRijndael.IV;

// Save Variables
MyEncryption me = new MyEncryption();
me.SetVariables(key, IV);

// CryptoStream
MemoryStream ms = new MemoryStream();
ICryptoTransform encryptor = myRijndael.CreateEncryptor(key,
IV);
CryptoStream cs = new CryptoStream(ms, encryptor,
CryptoStreamMode.Write);

// Write all data to the crypto stream and flush it
cs.Write(toEncrypt, 0, toEncrypt.Length);
cs.FlushFinalBlock();

// Get encrypted array of bytes
encrypted = ms.ToArray();

string final = Convert.ToBase64String(encrypted);

return final;
}

public static string Decrypt(string encryptedString)
{
byte[] key;
byte[] IV;
byte[] encrypted;
byte[] fromEncrypted;

MyEncryption me = new MyEncryption();
me.GetVariables(out key, out IV);

ASCIIEncoding textConverter = new ASCIIEncoding();
encrypted = textConverter.GetBytes(encryptedString);


RijndaelManaged myRijndael = new RijndaelManaged();
ICryptoTransform decryptor = myRijndael.CreateDecryptor(key,
IV);

MemoryStream ms = new MemoryStream(encrypted);

CryptoStream cs = new CryptoStream(ms, decryptor,
CryptoStreamMode.Read);

fromEncrypted = new byte[encrypted.Length];

cs.Read(fromEncrypted, 0, fromEncrypted.Length);

string decryptedString = Convert.ToBase64String(fromEncrypted);

return decryptedString;
}

private void SetVariables(byte[] key, byte[] IV)
{
Session["key"] = key;
Session["IV"] = IV;
}

private void GetVariables(out byte[] key, out byte[] IV)
{
key = (byte[])Session["key"];
IV = (byte[])Session["IV"];
}

public void CorruptVariables()
{
RijndaelManaged rm = new RijndaelManaged();
rm.GenerateKey();
rm.GenerateIV();

Session["key"] = rm.Key;
Session["IV"] = rm.IV;
}
}
}
 
J

Joe Kaplan \(MVP - ADSI\)

I may be misunderstanding your code, but it looks like your decrypt function
is taking the encrypted data which was encoded as a Base64 string and
converting that back to binary use ASCII! That doesn't make any sense. If
you encoded it with Base64, you must convert it back to binary with Base64.
You would then take the decrypted data and convert that back to a string
with ASCII.

Note that using ASCII is generally a bad idea though. You probably should
be using UTF8. UTF8 can round trip non-ASCII unicode characters, but will
be the same binary data as ASCII for ASCII characters. It is a no lose
proposition. ASCII inevitably ends up dropping characters when you least
expect it.

Joe K.

Bishoy George said:
Dear Jim,
In my case it is different, I just store the encrypted string in a Session
Variable and get it again from that Session Variable.

You said: "I can't see how you call those 2 functions"
My Answer is: by a web page:
- its url: http://testarea.nagyresearch.com/Test.aspx
- its code:

-------------------------- 1- Server html code ------------------------

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Test.aspx.cs"
Inherits="NagyResearch.Test" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Test Page</title>
</head>
<body onload="popup();">
<form id="form1" runat="server">
<div>
<asp:Label ID="Label1" runat="server" Text="Test To
Encrypt:"></asp:Label>
<asp:TextBox ID="txtToEncrypt" runat="server"
Width="274px"></asp:TextBox>
<br />
<br />
<asp:Button ID="btnEncrypt" runat="server"
OnClick="btnEncrypt_Click" Text="Encrypt!"
Width="157px" /><br />
<br />
<asp:Label ID="lblResult" runat="server" Height="46px"
Width="774px"></asp:Label><br />
<br />
<asp:Button ID="btnDecrypt" runat="server"
OnClick="btnDecrypt_Click" Text="Decrypt!"
Width="158px" /><br />
<br />
&nbsp;
<asp:TextBox ID="txtDecryptedResult" runat="server" Height="53px"
Width="770px"></asp:TextBox></div>
</form>
</body>
</html>


--------------------------------- 2- Code
Behind -----------------------------------

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text;

namespace NagyResearch
{
public partial class Test : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
protected void btnEncrypt_Click(object sender, EventArgs e)
{
lblResult.Text = MyEncryption.Encrypt(txtToEncrypt.Text);
}
protected void btnDecrypt_Click(object sender, EventArgs e)
{
txtDecryptedResult.Text = MyEncryption.Decrypt(lblResult.Text);
}
}
}


--------------------------------------------------- Class
Code ------------------------------------------------

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Text;
using System.Security.Cryptography;

namespace NagyResearch
{
/// <summary>
/// Summary description for MyEncryption
/// </summary>
public class MyEncryption : System.Web.UI.Page
{
public MyEncryption()
{
//
// TODO: Add constructor logic here
//
}

public static string Encrypt(string original)
{
byte[] encrypted; // here we put encrypted array of bytes
byte[] toEncrypt; // here we put original array of bytes to
encrypt them // also called buffer
byte[] key; // Secret Key for encryption
byte[] IV; // Initialization Vector

// Convert a string to a byte array /////// VERY IMPORTANT
///////
ASCIIEncoding textConverter = new ASCIIEncoding();
toEncrypt = textConverter.GetBytes(original);

// Create a new key and initialization vector
RijndaelManaged myRijndael = new RijndaelManaged();
myRijndael.GenerateKey();
myRijndael.GenerateIV();
// Get the key and IV
key = myRijndael.Key;
IV = myRijndael.IV;

// Save Variables
MyEncryption me = new MyEncryption();
me.SetVariables(key, IV);

// CryptoStream
MemoryStream ms = new MemoryStream();
ICryptoTransform encryptor = myRijndael.CreateEncryptor(key,
IV);
CryptoStream cs = new CryptoStream(ms, encryptor,
CryptoStreamMode.Write);

// Write all data to the crypto stream and flush it
cs.Write(toEncrypt, 0, toEncrypt.Length);
cs.FlushFinalBlock();

// Get encrypted array of bytes
encrypted = ms.ToArray();

string final = Convert.ToBase64String(encrypted);

return final;
}

public static string Decrypt(string encryptedString)
{
byte[] key;
byte[] IV;
byte[] encrypted;
byte[] fromEncrypted;

MyEncryption me = new MyEncryption();
me.GetVariables(out key, out IV);

ASCIIEncoding textConverter = new ASCIIEncoding();
encrypted = textConverter.GetBytes(encryptedString);


RijndaelManaged myRijndael = new RijndaelManaged();
ICryptoTransform decryptor = myRijndael.CreateDecryptor(key,
IV);

MemoryStream ms = new MemoryStream(encrypted);

CryptoStream cs = new CryptoStream(ms, decryptor,
CryptoStreamMode.Read);

fromEncrypted = new byte[encrypted.Length];

cs.Read(fromEncrypted, 0, fromEncrypted.Length);

string decryptedString = Convert.ToBase64String(fromEncrypted);

return decryptedString;
}

private void SetVariables(byte[] key, byte[] IV)
{
Session["key"] = key;
Session["IV"] = IV;
}

private void GetVariables(out byte[] key, out byte[] IV)
{
key = (byte[])Session["key"];
IV = (byte[])Session["IV"];
}

public void CorruptVariables()
{
RijndaelManaged rm = new RijndaelManaged();
rm.GenerateKey();
rm.GenerateIV();

Session["key"] = rm.Key;
Session["IV"] = rm.IV;
}
}
}


-------------------------------------------------------------------------------------------------------------------------------



Jim Andersen said:
I can't see how you call those 2 functions, but I had something of the
same, I encrypted a string, stored it in a database table, and later
decrypted it. Had the same problem U did. Until I found out the field in
the table wasn't long enough to hold all of the encrypted string. So I
didn't pass the encrypted string to my decrypt fundtion. But a cut-off
version of the string.

/jim
Click to expand...
Click to expand...
 
B

Bishoy George

Dear Joe Kaplan,
You are brilliant. Thank you. The code is working now.

This is the new code after your 2 modifications:
-------------------------------------
using System;

using System.Data;

using System.Configuration;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.IO;

using System.Text;

using System.Security.Cryptography;

namespace NagyResearch

{

/// <summary>

/// Summary description for MyEncryption

/// </summary>

public class MyEncryption : System.Web.UI.Page

{

public MyEncryption()

{

//

// TODO: Add constructor logic here

//

}

public static string Encrypt(string original)

{

byte[] encrypted; // here we put encrypted array of bytes

byte[] toEncrypt; // here we put original array of bytes to encrypt them //
also called buffer

byte[] key; // Secret Key for encryption

byte[] IV; // Initialization Vector

// Convert a string to a byte array /////// VERY IMPORTANT ///////

UTF8Encoding utf8Converter = new UTF8Encoding();

toEncrypt = utf8Converter.GetBytes(original);

// Create a new key and initialization vector

RijndaelManaged myRijndael = new RijndaelManaged();

myRijndael.GenerateKey();

myRijndael.GenerateIV();

// Get the key and IV

key = myRijndael.Key;

IV = myRijndael.IV;

// Save Variables

MyEncryption me = new MyEncryption();

me.SetVariables(key, IV);

// CryptoStream

MemoryStream ms = new MemoryStream();

ICryptoTransform encryptor = myRijndael.CreateEncryptor(key, IV);

CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write);

// Write all data to the crypto stream and flush it

cs.Write(toEncrypt, 0, toEncrypt.Length);

cs.FlushFinalBlock();

// Get encrypted array of bytes

encrypted = ms.ToArray();

string encryptedString = Convert.ToBase64String(encrypted);

return encryptedString;

}

public static string Decrypt(string encryptedString)

{

byte[] key;

byte[] IV;

byte[] encrypted;

byte[] fromEncrypted;

MyEncryption me = new MyEncryption();

me.GetVariables(out key, out IV);

encrypted = Convert.FromBase64String(encryptedString);

RijndaelManaged myRijndael = new RijndaelManaged();

ICryptoTransform decryptor = myRijndael.CreateDecryptor(key, IV);

MemoryStream ms = new MemoryStream(encrypted);

CryptoStream cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read);

fromEncrypted = new byte[encrypted.Length];

cs.Read(fromEncrypted, 0, fromEncrypted.Length);

UTF8Encoding utf8Converter = new UTF8Encoding();

string decryptedString = utf8Converter.GetString(fromEncrypted);

return decryptedString;

}

private void SetVariables(byte[] key, byte[] IV)

{

Session["key"] = key;

Session["IV"] = IV;

}

private void GetVariables(out byte[] key, out byte[] IV)

{

key = (byte[])Session["key"];

IV = (byte[])Session["IV"];

}

public void CorruptVariables()

{

RijndaelManaged rm = new RijndaelManaged();

rm.GenerateKey();

rm.GenerateIV();

Session["key"] = rm.Key;

Session["IV"] = rm.IV;

}

}

}
 

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