.NET encryption

G

Guest

Hi all

I have a very specific question. Recently I've created a class that performs
a basic encryption on strings passed to it. The encrypted data is returned as
a string and then passed over the network via a WebService. The encryption is
done trough a basic use of Memorystream, CyptoStream and an encryption class
(I'm using RijndaelManaged right now, but any other method would be good
too). After a few errors and trials I've discovered that the only way any
encryption method works (both for encrypting an decrypting) is by
transferring the string into byte data (and recovering it from byte data)
using the System.Text.Encoding.Unicode methods. Trying to do the same thing
with ASCII, UTF-7 or UTF-8 only results in the encryption methods throwing
all sorts of different exceptions (Incorrect data, Invalid data length, PKSC7
padding is invalid, .... and so on).

This is all good (I've managed to make the encryption work in both ways),
but here is my problem: sometimes (depending on wich string is encrypted and
with what key) the generated cipherstring causes problems when passing it
over a network. More specific: I get errors about the XML not being in the
correct format and so on.

My question: is there any way of making the encryption methods work using
ASCII, UTF-7 or UTF-8?
OR
Is there any way of passing Unicode text over a Webservice (thus via SOAP en
XML) without generating errors?

For your information, here's the code of the encryption class I've created:

using System;
using System.IO;
using System.Security.Cryptography;


namespace EncryptionTest
{
/// <summary>
/// A class that uses the Rijndael encryption method to encrypt or decrypt
small strings.
/// </summary>
public class RijndaelCrypt
{
private RijndaelManaged rdm;

public RijndaelCrypt()
{
rdm = new RijndaelManaged();
rdm.Padding = PaddingMode.PKCS7;
}

public string EncryptString(string encryptString, string key)
{
try
{
byte[] byteKey = CreateKey(key);
byte[] byteIV = CreateIV(key);
byte[] byteEncryptString =
System.Text.Encoding.Unicode.GetBytes(encryptString);
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, rdm.CreateEncryptor(byteKey,
byteIV), CryptoStreamMode.Write);
cs.Write(byteEncryptString, 0, byteEncryptString.Length);
cs.Close();
byte[] byteEncryptedString = ms.ToArray();
ms.Close();
string encryptedString =
System.Text.Encoding.Unicode.GetString(byteEncryptedString);
return encryptedString;
}
catch(Exception e)
{
// Popup pp = new Popup();
// pp.Message = e.Message + "\n" + e.StackTrace;
// pp.Show();
System.Windows.Forms.MessageBox.Show(e.Message + "\n" + e.StackTrace);
}
return "";
}

public string DecryptString(string decryptString, string key)
{
try
{

byte[] byteKey = CreateKey(key);
byte[] byteIV = CreateIV(key);
byte[] byteDecryptString =
System.Text.Encoding.Unicode.GetBytes(decryptString);
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, rdm.CreateDecryptor(byteKey,
byteIV), CryptoStreamMode.Write);
cs.Write(byteDecryptString, 0, byteDecryptString.Length);
cs.Close();
byte[] byteDecryptedString = ms.ToArray();
ms.Close();
string decryptedString =
System.Text.Encoding.Unicode.GetString(byteDecryptedString);
return decryptedString;
}
catch(Exception e)
{
Popup pp = new Popup();
// pp.Message = e.Message + "\n" + e.StackTrace;
// pp.Show();
System.Windows.Forms.MessageBox.Show(e.Message + "\n" + e.StackTrace);
}
return "";
}

private byte[] CreateKey(string key)
{
byte[] byteKey ;
byte[] byteSalt = System.Text.Encoding.Unicode.GetBytes("salt");
PasswordDeriveBytes pdb = new PasswordDeriveBytes(key,byteSalt);
byteKey = pdb.GetBytes(32);
return byteKey;
}

private byte[] CreateIV(string IV)
{
byte[] byteKey ;
byte[] byteSalt = System.Text.Encoding.Unicode.GetBytes("salt");
PasswordDeriveBytes pdb = new PasswordDeriveBytes(IV,byteSalt);
byteKey = pdb.GetBytes(16);
return byteKey;
}
}
}
 
D

Damien

Bmxpert said:
Hi all

I have a very specific question. Recently I've created a class that performs
a basic encryption on strings passed to it. The encrypted data is returned as
a string and then passed over the network via a WebService. The encryption is
done trough a basic use of Memorystream, CyptoStream and an encryption class
(I'm using RijndaelManaged right now, but any other method would be good
too). After a few errors and trials I've discovered that the only way any
encryption method works (both for encrypting an decrypting) is by
transferring the string into byte data (and recovering it from byte data)
using the System.Text.Encoding.Unicode methods. Trying to do the same thing
with ASCII, UTF-7 or UTF-8 only results in the encryption methods throwing
all sorts of different exceptions (Incorrect data, Invalid data length, PKSC7
padding is invalid, .... and so on).

This is all good (I've managed to make the encryption work in both ways),
but here is my problem: sometimes (depending on wich string is encrypted and
with what key) the generated cipherstring causes problems when passing it
over a network. More specific: I get errors about the XML not being in the
correct format and so on.

My question: is there any way of making the encryption methods work using
ASCII, UTF-7 or UTF-8?
OR
Is there any way of passing Unicode text over a Webservice (thus via SOAP en
XML) without generating errors?

For your information, here's the code of the encryption class I've created:
Click to expand...
Convert.ToBase64String() and Convert.FromBase64String() may be your
friends...
 
K

Kevin Spencer

You can use the Convert.ToBase64String method to serialize the bytes, and
the Convert.FromBase64String method to deserialize them.

--
HTH,

Kevin Spencer
Microsoft MVP
Professional Numbskull

Hard work is a medication for which
there is no placebo.

Bmxpert said:
Hi all

I have a very specific question. Recently I've created a class that
performs
a basic encryption on strings passed to it. The encrypted data is returned
as
a string and then passed over the network via a WebService. The encryption
is
done trough a basic use of Memorystream, CyptoStream and an encryption
class
(I'm using RijndaelManaged right now, but any other method would be good
too). After a few errors and trials I've discovered that the only way any
encryption method works (both for encrypting an decrypting) is by
transferring the string into byte data (and recovering it from byte data)
using the System.Text.Encoding.Unicode methods. Trying to do the same
thing
with ASCII, UTF-7 or UTF-8 only results in the encryption methods throwing
all sorts of different exceptions (Incorrect data, Invalid data length,
PKSC7
padding is invalid, .... and so on).

This is all good (I've managed to make the encryption work in both ways),
but here is my problem: sometimes (depending on wich string is encrypted
and
with what key) the generated cipherstring causes problems when passing it
over a network. More specific: I get errors about the XML not being in the
correct format and so on.

My question: is there any way of making the encryption methods work using
ASCII, UTF-7 or UTF-8?
OR
Is there any way of passing Unicode text over a Webservice (thus via SOAP
en
XML) without generating errors?

For your information, here's the code of the encryption class I've
created:

using System;
using System.IO;
using System.Security.Cryptography;


namespace EncryptionTest
{
/// <summary>
/// A class that uses the Rijndael encryption method to encrypt or decrypt
small strings.
/// </summary>
public class RijndaelCrypt
{
private RijndaelManaged rdm;

public RijndaelCrypt()
{
rdm = new RijndaelManaged();
rdm.Padding = PaddingMode.PKCS7;
}

public string EncryptString(string encryptString, string key)
{
try
{
byte[] byteKey = CreateKey(key);
byte[] byteIV = CreateIV(key);
byte[] byteEncryptString =
System.Text.Encoding.Unicode.GetBytes(encryptString);
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, rdm.CreateEncryptor(byteKey,
byteIV), CryptoStreamMode.Write);
cs.Write(byteEncryptString, 0, byteEncryptString.Length);
cs.Close();
byte[] byteEncryptedString = ms.ToArray();
ms.Close();
string encryptedString =
System.Text.Encoding.Unicode.GetString(byteEncryptedString);
return encryptedString;
}
catch(Exception e)
{
// Popup pp = new Popup();
// pp.Message = e.Message + "\n" + e.StackTrace;
// pp.Show();
System.Windows.Forms.MessageBox.Show(e.Message + "\n" + e.StackTrace);
}
return "";
}

public string DecryptString(string decryptString, string key)
{
try
{

byte[] byteKey = CreateKey(key);
byte[] byteIV = CreateIV(key);
byte[] byteDecryptString =
System.Text.Encoding.Unicode.GetBytes(decryptString);
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, rdm.CreateDecryptor(byteKey,
byteIV), CryptoStreamMode.Write);
cs.Write(byteDecryptString, 0, byteDecryptString.Length);
cs.Close();
byte[] byteDecryptedString = ms.ToArray();
ms.Close();
string decryptedString =
System.Text.Encoding.Unicode.GetString(byteDecryptedString);
return decryptedString;
}
catch(Exception e)
{
Popup pp = new Popup();
// pp.Message = e.Message + "\n" + e.StackTrace;
// pp.Show();
System.Windows.Forms.MessageBox.Show(e.Message + "\n" + e.StackTrace);
}
return "";
}

private byte[] CreateKey(string key)
{
byte[] byteKey ;
byte[] byteSalt = System.Text.Encoding.Unicode.GetBytes("salt");
PasswordDeriveBytes pdb = new PasswordDeriveBytes(key,byteSalt);
byteKey = pdb.GetBytes(32);
return byteKey;
}

private byte[] CreateIV(string IV)
{
byte[] byteKey ;
byte[] byteSalt = System.Text.Encoding.Unicode.GetBytes("salt");
PasswordDeriveBytes pdb = new PasswordDeriveBytes(IV,byteSalt);
byteKey = pdb.GetBytes(16);
return byteKey;
}
}
}
Click to expand...
 
G

Guest

I've tried this at home .NET2.0 and it seems to give me a string that will
not cause network problems (no chinese characters or unrepresentable
squares). I'll try this tomorrow at work (VS 2003) to see if it works. I'm
guessing it will.

Thank you very much for your quick and usefull responses...
Bye

Kevin Spencer said:
You can use the Convert.ToBase64String method to serialize the bytes, and
the Convert.FromBase64String method to deserialize them.

--
HTH,

Kevin Spencer
Microsoft MVP
Professional Numbskull

Hard work is a medication for which
there is no placebo.

Bmxpert said:
Hi all

I have a very specific question. Recently I've created a class that
performs
a basic encryption on strings passed to it. The encrypted data is returned
as
a string and then passed over the network via a WebService. The encryption
is
done trough a basic use of Memorystream, CyptoStream and an encryption
class
(I'm using RijndaelManaged right now, but any other method would be good
too). After a few errors and trials I've discovered that the only way any
encryption method works (both for encrypting an decrypting) is by
transferring the string into byte data (and recovering it from byte data)
using the System.Text.Encoding.Unicode methods. Trying to do the same
thing
with ASCII, UTF-7 or UTF-8 only results in the encryption methods throwing
all sorts of different exceptions (Incorrect data, Invalid data length,
PKSC7
padding is invalid, .... and so on).

This is all good (I've managed to make the encryption work in both ways),
but here is my problem: sometimes (depending on wich string is encrypted
and
with what key) the generated cipherstring causes problems when passing it
over a network. More specific: I get errors about the XML not being in the
correct format and so on.

My question: is there any way of making the encryption methods work using
ASCII, UTF-7 or UTF-8?
OR
Is there any way of passing Unicode text over a Webservice (thus via SOAP
en
XML) without generating errors?

For your information, here's the code of the encryption class I've
created:

using System;
using System.IO;
using System.Security.Cryptography;


namespace EncryptionTest
{
/// <summary>
/// A class that uses the Rijndael encryption method to encrypt or decrypt
small strings.
/// </summary>
public class RijndaelCrypt
{
private RijndaelManaged rdm;

public RijndaelCrypt()
{
rdm = new RijndaelManaged();
rdm.Padding = PaddingMode.PKCS7;
}

public string EncryptString(string encryptString, string key)
{
try
{
byte[] byteKey = CreateKey(key);
byte[] byteIV = CreateIV(key);
byte[] byteEncryptString =
System.Text.Encoding.Unicode.GetBytes(encryptString);
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, rdm.CreateEncryptor(byteKey,
byteIV), CryptoStreamMode.Write);
cs.Write(byteEncryptString, 0, byteEncryptString.Length);
cs.Close();
byte[] byteEncryptedString = ms.ToArray();
ms.Close();
string encryptedString =
System.Text.Encoding.Unicode.GetString(byteEncryptedString);
return encryptedString;
}
catch(Exception e)
{
// Popup pp = new Popup();
// pp.Message = e.Message + "\n" + e.StackTrace;
// pp.Show();
System.Windows.Forms.MessageBox.Show(e.Message + "\n" + e.StackTrace);
}
return "";
}

public string DecryptString(string decryptString, string key)
{
try
{

byte[] byteKey = CreateKey(key);
byte[] byteIV = CreateIV(key);
byte[] byteDecryptString =
System.Text.Encoding.Unicode.GetBytes(decryptString);
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, rdm.CreateDecryptor(byteKey,
byteIV), CryptoStreamMode.Write);
cs.Write(byteDecryptString, 0, byteDecryptString.Length);
cs.Close();
byte[] byteDecryptedString = ms.ToArray();
ms.Close();
string decryptedString =
System.Text.Encoding.Unicode.GetString(byteDecryptedString);
return decryptedString;
}
catch(Exception e)
{
Popup pp = new Popup();
// pp.Message = e.Message + "\n" + e.StackTrace;
// pp.Show();
System.Windows.Forms.MessageBox.Show(e.Message + "\n" + e.StackTrace);
}
return "";
}

private byte[] CreateKey(string key)
{
byte[] byteKey ;
byte[] byteSalt = System.Text.Encoding.Unicode.GetBytes("salt");
PasswordDeriveBytes pdb = new PasswordDeriveBytes(key,byteSalt);
byteKey = pdb.GetBytes(32);
return byteKey;
}

private byte[] CreateIV(string IV)
{
byte[] byteKey ;
byte[] byteSalt = System.Text.Encoding.Unicode.GetBytes("salt");
PasswordDeriveBytes pdb = new PasswordDeriveBytes(IV,byteSalt);
byteKey = pdb.GetBytes(16);
return byteKey;
}
}
}
Click to expand...
Click to expand...
 

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments. After that, you can post your question and our members will help you out.

Ask a Question

Similar Threads

How to decrypt a string? 7
Encrypt text to only viewable characters?? 3
Problem with encryption/decryption 7
PKCS7 padding is invalid and cannot be removed. 1
Web app security 4
Using RijndaelManaged 3
Rijndael Decrypt returning escape characters at end of string 2
Same encryption codes cannot decrypt password from .NET 1.0 to 2.0 4

Top