Google has denied that the current version of its reCAPTCHA captcha service contains vulnerabilities which make it easier for spammers to guess displayed words using automated scripts.

At the weekend, software developer Jonathan Wilkins published a document describing a procedure which can be used to increase the hit rate for automatic recognition of Google captchas to nearly 18 per cent. This would make the reCAPTCHA procedure as good as cracked, since it would allow botnets, for example, to create large numbers of email accounts with reputable providers and use them to send spam.

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