Sage Pay Forms V3.00 AES-128 Encryption VB.Net - vb.net

Question

I thought I would post this as I did not find an off-the-shelf solution for the AES encryption needed for the V3.00 upgrade.
The SagePay C# solution example for some reason did not have have an encryption/decryption code example in it as far as I could see.
I cobbled together the code from existing posts and the RijndaelManaged Class VB example (https://msdn.microsoft.com/en-us/library/system.security.cryptography.rijndaelmanaged(v=vs.110).aspx?cs-save-lang=1&cs-lang=vb#code-snippet-1)....
Imports System.Security.Cryptography
Public Shared Function AESEncryption(ByVal strCrypt As String) As String
Dim keyAndIvBytes As [Byte]() = UTF8Encoding.UTF8.GetBytes(strEncryptionPassword)
' Create a new instance of the RijndaelManaged
' class. This generates a new key and initialization
' vector (IV).
Using AES As New RijndaelManaged()
' Set the mode, padding and block size for the key
AES.Padding = PaddingMode.PKCS7
AES.Mode = CipherMode.CBC
AES.KeySize = 128
AES.BlockSize = 128
' Encrypt the string to an array of bytes.
Dim encrypted As Byte() = EncryptStringToBytes(strCrypt, keyAndIvBytes, keyAndIvBytes)
AESEncryption = "#" & BitConverter.ToString(encrypted).Replace("-", "").ToUpper
End Using
End Function
Public Shared Function AESDecryption(ByVal strCrypt As String) As String
Dim keyAndIvBytes As [Byte]() = UTF8Encoding.UTF8.GetBytes(strEncryptionPassword)
' Create a new instance of the RijndaelManaged
' class. This generates a new key and initialization
' vector (IV).
Using AES As New RijndaelManaged()
' Set the mode, padding and block size for the key
AES.Padding = PaddingMode.PKCS7
AES.Mode = CipherMode.CBC
AES.KeySize = 128
AES.BlockSize = 128
Dim encryptedData As Byte() = StringToByteArray(strCrypt.Remove(0, 1))
Dim roundtrip As String = DecryptStringFromBytes(encryptedData, keyAndIvBytes, keyAndIvBytes)
AESDecryption = roundtrip
End Using
End Function
Shared Function byteArrayToHexString(ByVal ba As Byte()) As String
Return BitConverter.ToString(ba).Replace("-", "")
End Function
Shared Function StringToByteArray(ByVal hex As String) As Byte()
Return Enumerable.Range(0, hex.Length).Where(Function(x) x Mod 2 = 0).[Select](Function(x) Convert.ToByte(hex.Substring(x, 2), 16)).ToArray()
End Function
Shared Function EncryptStringToBytes(ByVal plainText As String, ByVal Key() As Byte, ByVal IV() As Byte) As Byte()
' Check arguments.
If plainText Is Nothing OrElse plainText.Length <= 0 Then
Throw New ArgumentNullException("plainText")
End If
If Key Is Nothing OrElse Key.Length <= 0 Then
Throw New ArgumentNullException("Key")
End If
If IV Is Nothing OrElse IV.Length <= 0 Then
Throw New ArgumentNullException("IV")
End If
Dim encrypted() As Byte
' Create an RijndaelManaged object
' with the specified key and IV.
Using AES As New RijndaelManaged()
AES.Padding = PaddingMode.PKCS7
AES.Mode = CipherMode.CBC
AES.KeySize = 128
AES.BlockSize = 128
AES.Key = Key
AES.IV = IV
' Create a decrytor to perform the stream transform.
Dim encryptor As ICryptoTransform = AES.CreateEncryptor(AES.Key, AES.IV)
' Create the streams used for encryption.
Using msEncrypt As New MemoryStream()
Using csEncrypt As New CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write)
Using swEncrypt As New StreamWriter(csEncrypt)
'Write all data to the stream.
swEncrypt.Write(plainText)
End Using
encrypted = msEncrypt.ToArray()
End Using
End Using
End Using
' Return the encrypted bytes from the memory stream.
Return encrypted
End Function 'EncryptStringToBytes
Shared Function DecryptStringFromBytes(ByVal cipherText() As Byte, ByVal Key() As Byte, ByVal IV() As Byte) As String
' Check arguments.
If cipherText Is Nothing OrElse cipherText.Length <= 0 Then
Throw New ArgumentNullException("cipherText")
End If
If Key Is Nothing OrElse Key.Length <= 0 Then
Throw New ArgumentNullException("Key")
End If
If IV Is Nothing OrElse IV.Length <= 0 Then
Throw New ArgumentNullException("IV")
End If
' Declare the string used to hold
' the decrypted text.
Dim plaintext As String = Nothing
' Create an RijndaelManaged object
' with the specified key and IV.
Using AES As New RijndaelManaged
AES.Padding = PaddingMode.PKCS7
AES.Mode = CipherMode.CBC
AES.KeySize = 128
AES.BlockSize = 128
'AES.Key = Key
'AES.IV = IV
' Create a decrytor to perform the stream transform.
Dim decryptor As ICryptoTransform = AES.CreateDecryptor(Key, IV)
' Create the streams used for decryption.
Using msDecrypt As New MemoryStream(cipherText)
Using csDecrypt As New CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read)
Using srDecrypt As New StreamReader(csDecrypt)
' Read the decrypted bytes from the decrypting stream
' and place them in a string.
plaintext = srDecrypt.ReadToEnd()
End Using
End Using
End Using
End Using
Return plaintext
End Function
Hopefully this will be of use especially as there is only 6 weeks left to migrate to V3.00 and all the V2 options are switched off.

Answer 1

Maybe I'm being silly here but if you reference the SagePay.IntegrationKit.DotNet dll you should have access to their Crytography class.
At least thats what I've done; added the .dll as a reference, imported it as the top of the file then used Cryptography.DecodeAndDecrypt & Cryptography.EncryptAndEncode.

Answer 2

c# AES Decryption
Is a great thread for SagePay C# AES encryption needed for the V3.00 upgrade.