Encoding newline in VB.NET for HMAC SHA1 - vb.net

Question

I'm having a problem authenticating an API with OAuth. I can get it work fine in Python, but not in VB.Net. I realised the issue is that SHA1 algorithm is returning a different value in Python and VB.NET for the what I thought was the same message. This only seems to be the case when there is a newline character "\n" in the message (which there has to be for the API call). Using Environment.NewLine doesn't seem to help.
The code I'm using (based on this answer) is here, with the expected values I get from my Python program:
Public Sub Main()
' Expect D/5B78PD9pFhmqZQi3eenPBy6ks=
' Get D/5B78PD9pFhmqZQi3eenPBy6ks=
console.writeline(getHash("a", "msg"))
' Expect yuuq6RwtwkoJ6n3PquGFx60MLas=
' Get uv4AwQjvYeCTajhHw7EFtPlJfCE=
console.writeline(getHash("a", "msg\n"))
' Expect yuuq6RwtwkoJ6n3PquGFx60MLas=
' Get efRfAnmIN/C/YX/UPHVPFY5VjJg=
console.writeline(getHash("a", "msg" + Environment.NewLine))
End Sub
Public Function getHash(ByVal key As String, ByVal msg As String) As String
Dim myEncoder As New System.Text.UTF8Encoding
Dim keyBytes() As Byte = myEncoder.GetBytes(key)
Dim msgBytes() As Byte = myEncoder.GetBytes(msg)
Dim myHMACSHA1 As New System.Security.Cryptography.HMACSHA1(keyBytes)
Dim HashCode As Byte() = myHMACSHA1.ComputeHash(msgBytes)
Return Convert.ToBase64String(HashCode)
End Function
In case it's useful, my Python program is:
import base64
import hashlib
import hmac
key = "a"
msg = "msg\n"
key_byte = key.encode('utf-8')
msg_byte = msg.encode('utf-8')
h = hmac.new(key_byte, msg_byte, hashlib.sha1)
print base64.b64encode(h.digest()) # yuuq6RwtwkoJ6n3PquGFx60MLas=
My guess is it's something to do with how the newline character is encoded, but I can't figure out how to solve it.

Answer 1

To start with I'd just like to point out that \n in VB.NET does not represent a new line character. It will literally just become \n.
Environment.NewLine adapts to the current OS. Different operating systems use different line endings. The issue here is that the Python code is using a Line Feed character (\n) as a new line indicator, but since Environment.NewLine adapts to the OS it will return Windows' line ending, which is Carriage Return + Line Feed (\r\n).
Therefore if you want it to match the Python code you've got to be sure to insert a Line Feed only. For instance:
Console.WriteLine(getHash("a", "msg" & vbLf))