Verifying the Identity of Someone Requesting Information Under the GDPR

Let’s start by giving you a bit of context.  A 2019 news story featured a presentation given at the Black Hat security conference in Las Vegas by a PhD student from Oxford University. The student decided to contact about 150 organisations to see how much information he could obtain on his fiancée (with her permission of course… and naturally all in the interest of academic research!).

Anyway, he managed to obtain a mine of ‘useful’ information including credit card and social security numbers, passwords, and even her mother’s maiden name.  Of the organisations which responded, 24% simply accepted an email address and phone number as proof of identity and proceeded to send over all the files they had on his fiancée.  A further 16% requested easily forgeable ID information.

So why was it so easy to obtain all this information?

One suggestion is that organisations are concerned by the time restriction imposed by the GDPR to respond to requests, which reduced from 40 days to a month with the introduction of the GDPR.  As a result, they are looking to ‘process’ the request as quickly and efficiently as possible.  Another possible explanation is that front line staff receiving these subject access requests simply don’t know what they should and shouldn’t do as they haven’t been adequately trained.

So, what are the rules around verifying somebody’s identity?

The data controller MUST take reasonable steps to verify the individual if they are not known to them.

Here’s the guidance from the Information Commissioner’s Office:

You [controller] must comply with a request without undue delay and at the latest within one month of receipt of the request or (if later) within one month of receipt of: any requested information to clarify the request or any information requested to confirm the requester’s identity.

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The GDPR states in Recital 64: (remember that courts will use the ‘Recitals’ to inform judgement decisions, so they must be given serious consideration by any controllers)

“The controller should use all reasonable measures to verify the identity of a data subject who requests access, in particular in the context of online services and online identifiers.  A controller should not retain personal data for the sole purpose of being able to react to potential requests.”

This really couldn’t be much more explicit.  Verification of identity prior to disclosure is a clear obligation of any controller and is usually solidly practised, particularly within verbal interactions such as customer services, call centres etc., where individuals are required to identify themselves by providing information known only to them.  This includes requests made by a data subject’s representative (e.g., family member or spouse under power of attorney, court order, completion of a disclosure approval form etc.).  If verification cannot be achieved, the request should be denied, in writing, to the individual themselves.

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