(PHP using ActiveX) URL Signing for Google Maps API

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

Download Chilkat Crypt ActiveX

<?php

$crypt = new COM("Chilkat.Crypt2");

//  Any string argument automatically begins the 30-day trial.
$success = $crypt->UnlockComponent('Anything for 30-day trial.');
if ($success != 1) {
    print $crypt->lastErrorText() . "\n";
    exit;
}

//  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';

//  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=
print $sig . "\n";
?>