Password file manager - .NET encription!
I have too many passwords to remember. Not to mention all the creditcard numbers, bank accounts, urls, vpn settings... the list goes on.
I've had the need for a long time for an encrypted file then I could double click on and simply be prompted for a password to look at the file, make changes, copy a word or two, and close it. The closest I got was PGP, which I had to decrypt the file to disk, look at it, wipe it, or edit it, re-encrypt it, then wipe it. I JUST WANTED ONE WORD!!!
| Dan Glass | |
| Intermediate | |
| Language: | C# |
| Platform: | Windows |
| VS.NET | |
| External link |
Introduction
I have too many passwords to remember. Not to mention all the creditcard numbers, bank accounts, urls, vpn settings... the list goes on.
I've had the need for a long time for an encrypted file then I could double click on and simply be prompted for a password to look at the file, make changes, copy a word or two, and close it. The closest I got was PGP, which I had to decrypt the file to disk, look at it, wipe it, or edit it, re-encrypt it, then wipe it. I JUST WANTED ONE WORD!!!
Points of Interest
So I dragged a RichTextBox to my new project, added some menu items, and whalla! a simple UI to start. Two methods were needed, Encrypt() and Decrypt(), the rest was just wireup code - nothing exciting.
I used DES which uses a key and an IV. Both are 8 bytes long. To make the key and IV I use the password in a simple algorithum:
{
set
{
IV = value;
while ( IV.Length < 8 ) IV += value;
IV = IV.substring(0,8);
ArrayList a = new ArrayList();
foreach ( char c in value.ToCharArray() )
{
a.Add(c);
}
a.reverse();
String output = new String((char[])a.ToArray(typeof(char)));
KEY = output;
while ( KEY.Length < 8 ) KEY += output;
KEY = KEY.substring(0,8);
}
}
Admitantly this is not the best way, and I will update it when I get a chance. Most the code is wireup and file reads/writes, but the Encrypt() and Decrypt() methods are shown below:
{
MemoryStream writer = new MemoryStream();
writer.SetLength(0);
DESCryptoServiceProvider crypto = new DESCryptoServiceProvider();
crypto.Padding = System.Security.Cryptography.PaddingMode.PKCS7;
CryptoStream encStream = new CryptoStream(writer, crypto.CreateEncryptor(key, IV), CryptoStreamMode.write);
encStream.write(data,0, data.Length);
encStream.FlushFinalBlock();
byte[] b = new byte[writer.Length];
writer.Position = 0;
writer.Read( b, 0, (int)writer.Length );
encStream.Close();
writer.Close();
return b;
}
public static Stream Decrypt(byte[] data, byte[] key, byte[] IV)
{
MemoryStream writer = new MemoryStream();
writer.SetLength(0);
DESCryptoServiceProvider crypto = new DESCryptoServiceProvider();
crypto.Padding = System.Security.Cryptography.PaddingMode.PKCS7;
CryptoStream encStream = new CryptoStream(writer, crypto.CreateDecryptor(key, IV), CryptoStreamMode.write);
encStream.write(data,0, data.Length);
encStream.FlushFinalBlock();
writer.Position = 0;
return writer;
}
Notice the use of the Padding mode. You may run into alot of problems without it, incuding data loss. Also the keys need to be exactly the right size - 8 bytes long. I passed back the stream to make my code simpler, and I was planning to do it with the Encrypt() algorithum later.
Using the code
The demo is really all you need. Create a file association to your liking, so that you can double click on it to be prompted for a password to open it.
Here are the steps:
- Right hand click on the desktop -> New -> Text Document
- Rename the doc to anything with the file extension you want to use (i.e file.cpt)
- Right hand click on the file -> Open With -> Choose program
- Browse for the CryptoViewer and click Ok.
Dan Glass
www.olero.com
ORM.NET - Data access made easy
