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SHA Hash Problems in VB

SHA Hash Problems in VB, Problems using SHA Hasing algorithm.

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daviddolphin	13 Oct, 2008 - 05:42 AM Post #1
New D.I.C Head Joined: 13 Jun, 2008 Posts: 6 My Contributions	Hi all. I am trying to right a SHA hasing algorithm to store passwords in a database. This is the code I am using: CODE Dim UE As UnicodeEncoding = New UnicodeEncoding Dim HashValue As Byte(), MessageBytes As Byte() = UE.GetBytes(txtPre.Text) Dim SHhash As New SHA256Managed() Dim strHex As String = "" HashValue = SHhash.ComputeHash(MessageBytes) For Each b As Byte In HashValue strHex += [String].Format("{0:X2}", b) Next txtPost.Text = strHex However, the result that this produces differs from convertors I have found online. Such as: http://www.geektimedesign.com/tools-SHA-generator.cfm The difference in results is like this: 185F8DB32271FE25F561A6FC938B2E264306EC304EDA518007D1764826381969 A07E4F7343246C82B26F32E56F85418D518D8B2F2DAE77F1D56FE7AF50DB97AF For "Hello" With the websites generated SHA being the first and mine being the second. Can anyone help me understand what is going on here, as I am at a total losssss! Thank you much, David
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PsychoCoder

13 Oct, 2008 - 06:31 AM

Post #2

using DIC.Core;

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Try using SHA1CryptoServiceProvider instead of SHA256Managed, I believe that will give the results you are looking for.

Here's an example of using the SHA1CryptoServiceProvider


''' <summary>
''' method to hash the users password. To match the CAPICOM hash
''' we convert the string to UNICODE first
''' </summary>
''' <returns></returns>
Public Function HashString(ByVal str As String) As String
	'create our SHA1 provider
	Dim sha As SHA1 = New SHA1CryptoServiceProvider()
	Dim hashedValue As String = String.Empty
	'hash the data
	Dim hashedData As Byte() = sha.ComputeHash(Encoding.Unicode.GetBytes(str))

	'loop through each byte in the byte array
	For Each b As Byte In hashedData
		'convert each byte and append
		hashedValue += String.Format("{0,2:X2}", b )
	Next

	'return the hashed value
	Return hashedValue
End Function

Hope that helps

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daviddolphin	13 Oct, 2008 - 08:43 AM Post #3
New D.I.C Head Joined: 13 Jun, 2008 Posts: 6 My Contributions	The code you provided results in the same code I can produce with my code upon changing it to SHA1. However, this code does not correspond to code generated by ANY online SHA Hash generator. ...Any ideas? I am just concerned with future repeatability and standardization.
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