I've problem with Rijndael PKCS7

[Yuna84]

I've tried with a simple program in vb.net but when i'm going to
decript in my messagebox appears this message: PKCS7 padding is
invalid and cannot be removed.

I've found this few lines of codes in this site:
[url]http://www.dotnethell.it/articles/article.aspx?ArticleID=93[/url]

I've trasform in vb.net and this is the result

Imports system.security.cryptography
imports system.text
('I don't write the other normal imports)



Public Function Encode(ByVal s As String, ByVal chiave As String,
ByVal IV As String) As String
Dim ascii As New ASCIIEncoding
Dim rjm As New RijndaelManaged
rjm.KeySize = 128
rjm.BlockSize = 128
rjm.Key = ascii.GetBytes(chiave)
rjm.Key = ascii.GetBytes(IV)
Dim input() As Byte = Encoding.UTF7.GetBytes(s)
Dim output() As Byte =
rjm.CreateEncryptor().TransformFinalBlock(input, 0, input.Length)

Return Convert.ToBase64String(output)
End Function

Public Function Decode(ByVal s As String, ByVal chiave As String,
ByVal IV As String) As String
Dim rjm As New RijndaelManaged
Dim ascii As New ASCIIEncoding

rjm.KeySize = 128
rjm.BlockSize = 128
rjm.Key = ascii.GetBytes(chiave)
rjm.Key = ascii.GetBytes(IV)
Try
Dim input() As Byte = Convert.FromBase64String(s)
Dim output() As Byte =
rjm.CreateDecryptor().TransformFinalBlock(input, 0, input.Length)
Return Encoding.UTF7.GetString(output)
Catch e As Exception
MessageBox.Show(e.Message & " " & e.Source)
End Try
End Function

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e
As System.EventArgs) Handles Button1.Click
txtDecripta.Text = (Encode(txtCripta.Text, "AsDfGhJkLqPwOeIr",
"RiEoWpQlKjHgFdSa"))
End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e
As System.EventArgs) Handles Button2.Click
Console.WriteLine(Decode(txtDecripta.Text, "AsDfGhJkLqPwOeIr",
"RiEoWpQlKjHgFdSa"))
End Sub

Please. This is an emergency!!!! Can you help me???

[Hernan de Lahitte]

I suggest you to take a look at the sample in
[url]http://sourceforge.net/projects/ncrypto/[/url]
You will find a good sample in CryptoHelper.Encrypt or Decrypt methods.

In your sample, I notice the different encoding methods when encrypting and
decrypting and the algorithm usage is not very "clean" (Close() the alg
instance when finishing) nor readable.


Hernan de Lahitte
Lagash Systems S.A.
[url]http://weblogs.asp.net/hernandl[/url]


This posting is provided "AS IS" with no warranties, and confers no rights.

"Yuna84" <acquargento@yahoo.it> wrote in message
news:48144a5.0404160511.38097908@posting.google.co m...

> I've tried with a simple program in vb.net but when i'm going to
> decript in my messagebox appears this message: PKCS7 padding is
> invalid and cannot be removed.
>
> I've found this few lines of codes in this site:
> [url]http://www.dotnethell.it/articles/article.aspx?ArticleID=93[/url]
>
> I've trasform in vb.net and this is the result
>
> Imports system.security.cryptography
> imports system.text
> ('I don't write the other normal imports)
>
>
>
> Public Function Encode(ByVal s As String, ByVal chiave As String,
> ByVal IV As String) As String
> Dim ascii As New ASCIIEncoding
> Dim rjm As New RijndaelManaged
> rjm.KeySize = 128
> rjm.BlockSize = 128
> rjm.Key = ascii.GetBytes(chiave)
> rjm.Key = ascii.GetBytes(IV)
> Dim input() As Byte = Encoding.UTF7.GetBytes(s)
> Dim output() As Byte =
> rjm.CreateEncryptor().TransformFinalBlock(input, 0, input.Length)
>
> Return Convert.ToBase64String(output)
> End Function
>
> Public Function Decode(ByVal s As String, ByVal chiave As String,
> ByVal IV As String) As String
> Dim rjm As New RijndaelManaged
> Dim ascii As New ASCIIEncoding
>
> rjm.KeySize = 128
> rjm.BlockSize = 128
> rjm.Key = ascii.GetBytes(chiave)
> rjm.Key = ascii.GetBytes(IV)
> Try
> Dim input() As Byte = Convert.FromBase64String(s)
> Dim output() As Byte =
> rjm.CreateDecryptor().TransformFinalBlock(input, 0, input.Length)
> Return Encoding.UTF7.GetString(output)
> Catch e As Exception
> MessageBox.Show(e.Message & " " & e.Source)
> End Try
> End Function
>
> Private Sub Button1_Click(ByVal sender As System.Object, ByVal e
> As System.EventArgs) Handles Button1.Click
> txtDecripta.Text = (Encode(txtCripta.Text, "AsDfGhJkLqPwOeIr",
> "RiEoWpQlKjHgFdSa"))
> End Sub
>
> Private Sub Button2_Click(ByVal sender As System.Object, ByVal e
> As System.EventArgs) Handles Button2.Click
> Console.WriteLine(Decode(txtDecripta.Text, "AsDfGhJkLqPwOeIr",
> "RiEoWpQlKjHgFdSa"))
> End Sub
>
> Please. This is an emergency!!!! Can you help me???

[DotNetJunkies User]

Sometimes the problem is with an altered encrypted string. I found this out when I was trying to decrypt a string I had inadvertently changed to lower case.

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