(VB.NET) URL Signing for Google Maps API

Demonstrates how to sign a URL for the Google Maps API.

Download: Chilkat .NET Assemblies

Dim crypt As New Chilkat.Crypt2()

'  Any string argument automatically begins the 30-day trial.
Dim success As Boolean
success = crypt.UnlockComponent("Anything for 30-day trial.")
If (success <> true) Then
    TextBox1.Text = TextBox1.Text & crypt.LastErrorText & vbCrLf
    Exit Sub
End If


'  The output will be modified Base64.
'  Modified Base64 for URLs replaces the '+' and '/' characters
'  of standard Base64 with '-' and '_' respectively, so that these
'  Base64 signatures no longer need to be URL-encoded.
crypt.EncodingMode = "modBase64"

'  NOTE: At the time of this writing, the "modBase64" encoding mode is
'  available in the pre-release build only.  Send email to
'  support@chilkatsoft.com if you need a pre-release.  This feature will be
'  included in the next official release.

'  Set the hash algorithm to sha-1
crypt.HashAlgorithm = "sha-1"

Dim sig As String

'  Set the HMAC key (this is the private key provided by Google)
crypt.SetHmacKeyEncoded("vNIXE0xscrmjlyV-12Nj_BvUPaw=","modBase64")

'  Compute the URL signature
sig = crypt.HmacStringENC("/maps/api/geocode/json?address=New+York&sensor=false&client=clientID")

'  The result should be KrU1TzVQM7Ur0i8i7K3huiw3MsA=
TextBox1.Text = TextBox1.Text & sig & vbCrLf