md5 hash not working?

  • Thread starter Thread starter HamuNaptra
  • Start date Start date
H

HamuNaptra

Hi im trying to get a hash from a string and conert it back to a string

eg. "test" = "098f6bcd4621d373cade4e832627b4f6"

my function:


Private Function GenerateHash(ByVal SourceText As String) As String

Dim Ue As New UnicodeEncoding()
Dim ByteSourceText() As Byte = Ue.GetBytes(SourceText)
Dim Md5 As New MD5CryptoServiceProvider()
Dim ByteHash() As Byte = Md5.ComputeHash(ByteSourceText)

Return Encoding.ASCII.GetString(ByteHash)

End Function

when i call the function i get this:

"yAWeLsdBn1kOedfxt3S/5g=="
 
Hi
So where is the problem?
What whould you espected to get?
MD5 will encrypt irreversible your string ..
Possible use is password hiding pourpose...to store a obfuscated value not a
readable password.

Ceers,
Crirus
 
HamuNaptra said:
Hi im trying to get a hash from a string and conert it back to a string
eg. "test" = "098f6bcd4621d373cade4e832627b4f6"
my function:
Click to expand...

Your code is wrong. First, you're using a unicode encoding to convert "test"
to a byte string; you should use an ASCII encoding or you will never get the
hash result you mention above.
Second, the hash above is in hexadecimal format and the result of your
function appears to be in Base64 format. Here's a small method [in C#] to
convert your bytes to a hexadecimal string:

private static string BytesToHex(byte[] hash) {
StringBuilder sb = new StringBuilder(hash.Length * 2);
for(int i = 0; i < hash.Length; i++) {
sb.Append(hash.ToString("X2"));
}
return sb.ToString();
}

It shouldn't be too hard to port to VB.NET.

Regards,
Pieter Philippaerts
Managed SSL/TLS: http://www.mentalis.org/go.php?sl
 
Hi im trying to get a hash from a string and conert it back to a string

eg. "test" = "098f6bcd4621d373cade4e832627b4f6"

my function:


Private Function GenerateHash(ByVal SourceText As String) As String

Dim Ue As New UnicodeEncoding()
Dim ByteSourceText() As Byte = Ue.GetBytes(SourceText)
Dim Md5 As New MD5CryptoServiceProvider()
Dim ByteHash() As Byte = Md5.ComputeHash(ByteSourceText)

Return Encoding.ASCII.GetString(ByteHash)

End Function

when i call the function i get this:

"yAWeLsdBn1kOedfxt3S/5g=="
Click to expand...

I modified your function as follows and got the result you expected:

Private Function GenerateHash(ByVal SourceText As String) As String

'Dim Ue As New UnicodeEncoding
Dim ByteSourceText() As Byte = Encoding.Default.GetBytes(SourceText)

'Dim ByteSourceText() As Byte = Ue.GetBytes(SourceText)
Dim Md5 As New MD5CryptoServiceProvider

Dim ByteHash() As Byte = Md5.ComputeHash(ByteSourceText)

'Convert the Byte array to a hex string
Dim sb As New StringBuilder(32)
For x As Integer = 0 To ByteHash.Length - 1
If ByteHash(x) < 16 Then
sb.Append("0")
End If
sb.Append(Convert.ToString(ByteHash(x), 16))
Next

Return sb.ToString

End Function
 
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