<p>Let say that I have a website with some information that could be access externally. Those information need to be only change by the respected client. Example: Google Analytic or WordPress API key. How can I create a system that work like that (no matter the programming language)?</p>

[{'answer_id': 77300, 'author': 'Nikolai Prokoschenko', 'author_id': 6460, 'author_profile': 'https://Stackoverflow.com/users/6460', 'pm_score': 2, 'selected': False, 'text': '<p>Simple:</p>\n\n<ol>\n<li>Generate a key for each user</li>\n<li>Deny access for each request without this key</li>\n</ol>\n'}, {'answer_id': 77313, 'author': 'digiguru', 'author_id': 5055, 'author_profile': 'https://Stackoverflow.com/users/5055', 'pm_score': 0, 'selected': False, 'text': '<p>A good way of generating a key would be to store a GUID (Globally Unique Identifier) on each user record n the database. GUID is going to be unique and almost impossible to guess.</p>\n'}, {'answer_id': 77324, 'author': 'Aeon', 'author_id': 13289, 'author_profile': 'https://Stackoverflow.com/users/13289', 'pm_score': 5, 'selected': True, 'text': '<p>A number of smart people are working on a standard, and it\'s called <a href="http://oauth.net/" rel="noreferrer">OAuth</a>. It already has a number of <a href="http://oauth.net/code" rel="noreferrer">sample implementations</a>, so it\'s pretty easy to get started.</p>\n'}, {'answer_id': 77335, 'author': 'Ian P', 'author_id': 10853, 'author_profile': 'https://Stackoverflow.com/users/10853', 'pm_score': 1, 'selected': False, 'text': '<p>Currently, I use a concatenation of multiple MD5s with a salt. The MD5s are generated off of various concatenations of user data.</p>\n'}, {'answer_id': 25814785, 'author': 'steve', 'author_id': 70088, 'author_profile': 'https://Stackoverflow.com/users/70088', 'pm_score': 0, 'selected': False, 'text': '<p>There are also infrastructure services that manage all this for you like <a href="http://www.3scale.net" rel="nofollow">http://www.3scale.net</a> (disclosure I work there), <a href="http://www.mashery.com" rel="nofollow">http://www.mashery.com</a> and <a href="http://www.apigee.com/" rel="nofollow">http://www.apigee.com/</a>.</p>\n'}]
['https://Stackoverflow.com/questions/77280', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/13913/']