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Google’s ‘Secret’ Update Scans All Your Photos
(www.forbes.com)
This is a most excellent place for technology news and articles.
caller id is the thing that tells you the number. it isn't cheap to forge, but it's the only way a scan could reasonably effect anyone with more than half a brain. there is never a reason to send information to an unknown SMS number, or click on a link from a text message from an unknown number.