VS 2010 AES Encryption

Private Shared Function AES_EncryptString(ByVal input As String, ByVal pass As String, ByVal type As Integer) As String
            Dim AES = New System.Security.Cryptography.RijndaelManaged
            Dim HASH_AES
 
            Select Case type
                Case 0
                    HASH_AES = New System.Security.Cryptography.MD5CryptoServiceProvider
                Case 1
                    HASH_AES = New System.Security.Cryptography.SHA256CryptoServiceProvider
                Case 2
                    HASH_AES = New System.Security.Cryptography.SHA512CryptoServiceProvider
            End Select
 
            Dim encrypted As String = ""
            Try
                Dim hash(31) As Byte
                Dim temp As Byte() = HASH_AES.ComputeHash(System.Text.ASCIIEncoding.ASCII.GetBytes(pass))
                Array.Copy(temp, 0, hash, 0, 16)
                Array.Copy(temp, 0, hash, 15, 16)
                AES.Key = hash
 
                AES.Mode = Security.Cryptography.CipherMode.ECB
                Dim DESEncrypter As System.Security.Cryptography.ICryptoTransform = AES.CreateEncryptor
                Dim Buffer As Byte() = System.Text.ASCIIEncoding.ASCII.GetBytes(input)
                encrypted = Convert.ToBase64String(DESEncrypter.TransformFinalBlock(Buffer, 0, Buffer.Length))
                Return encrypted
            Catch ex As Exception
                Throw New Exception("Error: Unable to perform Encryption on string! See Exception: " & ex.ToString)
            End Try
        End Function