Crypto removing white spaces from byte array

  • Thread starter Thread starter Brian Mitchell
  • Start date Start date
B

Brian Mitchell

I'm sorry if this is the wrong group but I couldn't find one relating to
cryptography.



I have a byte array that I am encrypting using the System.Cryptography
classes and it encrypts just fine. However when I decrypt the array the
decryptor removes all the white spaces from the array (byte values of 255).
I've tried setting the padding to none but it doesn't work. As long as the
array doesn't have any white spaces in there it encrypts and decrypts
normally.



Anyone have any ideas on how to fix this?



Thanks!!

Brian
 
Brian said:
I have a byte array that I am encrypting using the System.Cryptography
classes and it encrypts just fine. However when I decrypt the array the
decryptor removes all the white spaces from the array (byte values of 255).
I've tried setting the padding to none but it doesn't work. As long as the
array doesn't have any white spaces in there it encrypts and decrypts
normally.

Anyone have any ideas on how to fix this?
Click to expand...

Could you show us some code (ideally, the smallest example that goes
wrong)? I just knocked this together and it performs as expected:


Imports System.Security.Cryptography
Imports System.Text
Imports System.IO

Module Module1

Sub Main()

Dim plaintext() As Byte = New Byte() {&H12, &H34, &H56, &H78,
&HFF, &H9A, &HFF, &HBC, &HFF, &HDE}

Console.Write("starting plaintext: ")
Console.WriteLine(OutHex(plaintext))

Dim algo As SymmetricAlgorithm = RijndaelManaged.Create
algo.GenerateKey()
algo.GenerateIV()
Dim key() As Byte = algo.Key
Dim iv() As Byte = algo.IV

Dim encryptor As ICryptoTransform = algo.CreateEncryptor
Dim encr() As Byte = encryptor.TransformFinalBlock(plaintext,
0, plaintext.Length)

Console.Write("encrypted : ")
Console.WriteLine(OutHex(encr))

Dim decryptor As ICryptoTransform = algo.CreateDecryptor
Dim decr() As Byte = decryptor.TransformFinalBlock(encr, 0,
encr.Length)

Console.Write("decrypted : ")
Console.WriteLine(OutHex(decr))

Console.ReadLine()
End Sub

Private Function OutHex(ByVal arr() As Byte) As String
Dim out As New StringBuilder(arr.Length * 3)

For index As Integer = 0 To arr.Length - 1
out.Append(arr(index).ToString("X").PadLeft(2, "0"c))
out.Append(" ")
Next

Return out.ToString
End Function

End Module

Output is:

starting plaintext: 12 34 56 78 FF 9A FF BC FF DE
encrypted : EF 64 FA 6A 2E A9 1F 29 9A 01 4C E4 4D 80 77 0A
decrypted : 12 34 56 78 FF 9A FF BC FF DE

As I would expect, there isn't any special treatment for bytes holding
255.
 
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