Possible Duplicates:
Is using Gravatar a security risk?
Is Gravatar a privacy risk?

Since the Gravatar is generated based on the email address. Is it possible to determine a user's email address based on their Gravatar?

marked as duplicate by Adam Davis, Arjan, The Unhandled Exception, Michael Mrozek, Josh K Feb 18 '11 at 20:22

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  • 1
    where is the duplicate question? – rubo77 Jun 19 '12 at 16:01
up vote 4 down vote accepted

The email addresses in Gravatar are stored as MD5 hashes. It's the same kind of one-way protection used in password storage.

  • 2
    But for avatars, the "password" might be much more easily guessed, and then validated against the hash. Like when assuming a display name might also be the user name at one of the main email providers. – Arjan Feb 18 '11 at 19:59
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    @chrisay It's only used for passwords by incompetent programmers, because brute-forcing md5 is fast. And for the same reason it sucks when hiding email addresses too. – CodesInChaos Jan 28 '12 at 16:54

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