vb.net rijndael limit to 64 character - vb.net

Question

i have problem while encrypt and decrypt using rijndael in vb.net.
it cannot work on string more than 64 character.
here is my code:
Private Function prepareRijn() As Rijndael
Dim KEY As String = Left(_KEY, 32)
Dim IV As String = Right(_KEY, 32)
Dim enc As New System.Text.UTF8Encoding
Dim byteKEY() As Byte = enc.GetBytes(KEY)
Dim byteIV() As Byte = enc.GetBytes(IV)
Dim alg As Rijndael = Rijndael.Create
alg.BlockSize = 256
alg.KeySize = 256
alg.Padding = PaddingMode.Zeros
alg.Mode = CipherMode.CBC
alg.Key = byteKEY
alg.IV = byteIV
Return alg
End Function
Function decrypt(ByVal encrypted As String) As String
encrypted = encrypted.Replace("Q2FrZQ==.", "")
Dim enc As New System.Text.UTF8Encoding
Dim alg As Rijndael = prepareRijn()
Dim ms As New MemoryStream
Dim cs As CryptoStream = New CryptoStream(ms, alg.CreateDecryptor, CryptoStreamMode.Write)
Dim data() As Byte = Convert.FromBase64String(encrypted)
cs.Write(data, 0, data.Length)
'ms.SetLength(data.Length)
Dim decrypted() As Byte
decrypted = ms.ToArray
cs.Close()
Return enc.GetString(decrypted)
End Function
Function encrypt(ByVal decrypt As String) As String
decrypt = decrypt + " "
Dim alg As Rijndael = prepareRijn()
Dim ms As New MemoryStream()
Dim cs As CryptoStream = New CryptoStream(ms, alg.CreateEncryptor(), CryptoStreamMode.Write)
Dim data() As Byte = System.Text.Encoding.UTF8.GetBytes(decrypt)
cs.Write(data, 0, data.Length)
'ms.SetLength(data.Length)
Dim encrypted() As Byte = ms.ToArray()
cs.Close()
Return Convert.ToBase64String(encrypted)
End Function
is there anything i miss during my rijndael configuration ?

Answer 1

I wrote complete Encryption Class for you. It works perfectly. It can be used for Both Strings and ByteArrays. This Class returns Encrypted Data in Base64, if you dont want Base64, just remove Conversion.
Imports System.Text
Imports System.Security.Cryptography
Imports System.IO
Imports System
Public Class Encryption
' Fields
Private Shared sIV As String = "Your IV Key Placed Here 32-Bytes"
Private Shared sKey As String = "Your SecKey Placed Here 32-Bytes"
' Methods
Public Shared Function DecryptRJ256(ByVal prm_text_to_decrypt As String) As String
Dim s As String = prm_text_to_decrypt
Dim managed As New RijndaelManaged With { _
.Padding = PaddingMode.Zeros, _
.Mode = CipherMode.ECB, _
.KeySize = &H100, _
.BlockSize = &H100 _
}
Dim rgbKey As Byte() = Nothing
Dim rgbIV As Byte() = Nothing
s = s.Replace("-", "+").Replace("_", "/").Replace("|", "=")
rgbKey = Encoding.ASCII.GetBytes(Encryption.sKey)
rgbIV = Encoding.ASCII.GetBytes(Encryption.sIV)
Dim transform As ICryptoTransform = managed.CreateDecryptor(rgbKey, rgbIV)
Dim buffer As Byte() = Convert.FromBase64String(s)
Dim buffer4 As Byte() = New Byte((buffer.Length + 1) - 1) {}
Dim stream As New MemoryStream(buffer)
Dim stream2 As New CryptoStream(stream, transform, CryptoStreamMode.Read)
stream2.Read(buffer4, 0, buffer4.Length)
Return Encoding.ASCII.GetString(buffer4)
End Function
Public Shared Function EncryptRJ256(ByVal prm_text_to_encrypt As String) As String
Dim s As String = prm_text_to_encrypt
Dim managed As New RijndaelManaged With { _
.Padding = PaddingMode.Zeros, _
.Mode = CipherMode.ECB, _
.KeySize = &H100, _
.BlockSize = &H100 _
}
Dim buffer As Byte() = Nothing
Dim rgbKey As Byte() = Nothing
Dim rgbIV As Byte() = Nothing
rgbKey = Encoding.ASCII.GetBytes(Encryption.sKey)
rgbIV = Encoding.ASCII.GetBytes(Encryption.sIV)
Dim transform As ICryptoTransform = managed.CreateEncryptor(rgbKey, rgbIV)
Dim stream As New MemoryStream
Dim stream2 As New CryptoStream(stream, transform, CryptoStreamMode.Write)
buffer = Encoding.ASCII.GetBytes(s)
stream2.Write(buffer, 0, buffer.Length)
stream2.FlushFinalBlock()
Return Convert.ToBase64String(stream.ToArray).Replace("+", "-").Replace("/", "_").Replace("=", "|")
End Function
Public Shared Function EncryptRJ256(ByVal ArrayByte As Byte()) As String
Dim managed As New RijndaelManaged With { _
.Padding = PaddingMode.Zeros, _
.Mode = CipherMode.ECB, _
.KeySize = &H100, _
.BlockSize = &H100 _
}
Dim rgbKey As Byte() = Nothing
Dim rgbIV As Byte() = Nothing
rgbKey = Encoding.ASCII.GetBytes(Encryption.sKey)
rgbIV = Encoding.ASCII.GetBytes(Encryption.sIV)
Dim transform As ICryptoTransform = managed.CreateEncryptor(rgbKey, rgbIV)
Dim stream As New MemoryStream
Dim stream2 As New CryptoStream(stream, transform, CryptoStreamMode.Write)
stream2.Write(ArrayByte, 0, ArrayByte.Length)
stream2.FlushFinalBlock()
Return Convert.ToBase64String(stream.ToArray).Replace("+", "-").Replace("/", "_").Replace("=", "|")
End Function
Public Shared Function getMD5Hash(ByVal input As String) As String
Dim md As MD5 = MD5.Create
Dim bytes As Byte() = Encoding.ASCII.GetBytes(input)
Dim buffer2 As Byte() = md.ComputeHash(bytes)
Dim builder As New StringBuilder
Dim i As Integer
For i = 0 To buffer2.Length - 1
builder.Append(buffer2(i).ToString("X2"))
Next i
Return builder.ToString
End Function
Public Shared Function FromBase64String(ByVal prm_text_to_decrypt As String) As String
Dim s As String = prm_text_to_decrypt
s = s.Replace("-", "+").Replace("_", "/").Replace("|", "=")
Dim buffer As Byte() = Convert.FromBase64String(s)
Return Encoding.ASCII.GetString(buffer)
End Function
End Class