Hashing

[Radiit]

How do you encrypt a string using DES and MD4 in vb.net 2003 or 2005

 

[vis781]

If you want to stay ultra secure and ahead of the game i would stop using DES, MD4 and even MD5 and they are becoming increasingly unstable. SHA-2 is a better bet and available in the framework. See this site for more details...

http://www.codeproject.com/useritems/GoodbyeMD5.asp

 

[Radiit]

Ok, but I have a MD5 hashed file to recover. So I decided to write a VB program for it rather than getting ready made softwares. So, can I have the code for it?

 

[JohnH]

Hashing is a one-way operation, you can't recover a hash, it's only used when possibly same input is hashed again to see if it match, like password checking.

 

[Radiit]

But I want MD4 hash, not MD5 or SHA.

 

[JohnH]

How do you encrypt a string using DES and MD4 in vb.net 2003 or 2005

Ok, but I have a MD5 hashed file to recover.

But I want MD4 hash, not MD5 or SHA.

Perhaps make up your mind about hashing algoritm targeted? .Net Framework don't support MD4. Also read my previous post again and accept what hashing is and the difference to encryption/decryption.

 

[cjard]

If you want to stay ultra secure and ahead of the game i would stop using DES, MD4 and even MD5 and they are becoming increasingly unstable. SHA-2 is a better bet and available in the framework. See this site for more details...

http://www.codeproject.com/useritems/GoodbyeMD5.asp

Agreed. I read in NewScientist that MD5 has recently been broken by a chinese professor..

http://en.epochtimes.com/news/7-1-11/50336.html

 

[Radiit]

DES Hash

Imports System
Imports System.Text
Imports System.Security
Imports System.Security.Cryptography
Imports Microsoft.VisualBasic
Imports Microsoft.VisualBasic.Strings
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim n As Byte() = System.Text.Encoding.ASCII.GetBytes("")
Dim u7 As Encoding = Encoding.UTF7
Dim desCrypto As DESCryptoServiceProvider = DESCryptoServiceProvider.Create()
Dim keyBytes() As Byte = u7.GetBytes(TextBox1.Text)
 
ReDim Preserve keyBytes(8 - 1)
ReDim Preserve n(8 - 1)
 
desCrypto.Key = keyBytes
desCrypto.IV = n
 
Dim pass() As Byte = _
System.Text.Encoding.ASCII.GetBytes(TextBox2.Text)
Dim ms As New System.IO.MemoryStream
Dim encStream As New CryptoStream(ms, _
desCrypto.CreateEncryptor(), _
System.Security.Cryptography.CryptoStreamMode.Write)
encStream.Write(pass, 0, pass.Length)
TextBox3.Text = BytesToHexString(ms.ToArray)
 
encStream.Flush()
encStream.FlushFinalBlock()
End Sub
 
Public Shared Function BytesToHexString(ByVal bytes As Byte()) As String
Dim hexString As StringBuilder = New StringBuilder(64)
Dim counter As Integer
 
For counter = 0 To bytes.Length - 1
hexString.Append(String.Format("{0:X2}", bytes(counter)))
Next
 
Return hexString.ToString()
End Function
End Class

For the above code I get the same hex string (DC22CC897735644B) when the
textbox2 is 12345678 and textbox1 is 2 or 3. I get the same repeated hex strings for 4 and 5, 6 and 7 and so on. Why is it like this and can somebody help in my coding?

 

[JohnH]

Does that really matter as long as you get same data back when you decrypt when using the same key?