VB.NET equivalent to PHP functions

I am currently working on an assignment to convert a Perl/PHP based intra-net project to an ASP.NET web application.

The complexity of the project has been significant as it involves the management of an internal Windows 2003 Active Directory setup for a large governmental organization, integrated with a proprietary ticketing system, and a Sql Server database. The (sometimes cryptic) non object-oriented PHP/Perl code together with a severely limited testing environment have only made the task that more difficult.

Anyways, I had to create VB.NET equivalent for some PHP functions while working on the migration. I am posting the functions here in the hope that they might be useful to someone googling around.

Currently, the PHP functions converted include md5, base64_encode, base64_decode, chunk_split, and mail.
I might add to this list of converted functions as and when I convert more of them depending upon requirements of my assignment.

So, here are the converted functions:

Public Module PhpToVb
	Public Function md5(ByVal input As String) As String
		Dim x As New System.Security.Cryptography.MD5CryptoServiceProvider()
		Dim bs As Byte() = System.Text.Encoding.UTF8.GetBytes(Input)
		bs = x.ComputeHash(bs)
		Dim s As New System.Text.StringBuilder()
		For Each b As Byte In bs
			s.Append(b.ToString("x2").ToLower())
		Next
		Dim password As String = s.ToString()
		Return password
	End Function

	Public Function base64_encode(ByVal input As String) As String
		Dim bytesToEncode As Byte()
		bytesToEncode = Encoding.UTF8.GetBytes(input)

		Dim encodedText As String
		encodedText = Convert.ToBase64String(bytesToEncode)

		Return (encodedText)
	End Function

	Public Function base64_decode(ByVal input As String) As String
		Dim decodedBytes As Byte()
		decodedBytes = Convert.FromBase64String(input)

		Dim decodedText As String
		decodedText = Encoding.UTF8.GetString(decodedBytes)

		Return (decodedText)
	End Function

	Public Function chunk_split(ByVal input As String, Optional ByVal chunkLen As Integer = 76, Optional ByVal sep As String = vbCr & vbLf) As String

		If (chunkLen < 1) Then
			Throw New ArgumentException("Invalid value for chunklen, must be greater than zero.")
		End If

		Return (String.Join(sep, System.Text.RegularExpressions.Regex.Split(input, ",{0," & chunkLen & "}", RegexOptions.Multiline)))
	End Function

	Public Sub mail(ByVal [to] As String, ByVal subject As String, ByVal body As String, ByVal headers As String)
		Dim split = headers.Split(vbCrLf)

		Dim mail As New System.Net.Mail.MailMessage

		For Each header As String In split
			Dim index As Integer = header.IndexOf(":")
			Dim key As String = header.Substring(0, index)
			Dim val As String = header.Substring(index + 1).Trim()

			mail.Headers.Add(key, val)
		Next

		mail.Subject = subject
		mail.Body = body

		mail.To.Add([to])
		Dim client As New System.Net.Mail.SmtpClient()

		client.Send(mail)

	End Sub
End Module