Tokenization and Your Private Data (5)

Recapping (last time):

While this series on tokenization has been a bomb with regular folks (my post on the BCTF and social media got 10x the traffic) one category of readers have really taken notice: tokenization vendors. I’ve gotten a number of emails, and some educational comments as well. (Hi guys!)

For the love of the vendors, I’ll repeat yesterdays postscript. I think I have been overly harsh on the cloud security vendors, because there are really two questions here, which have very different answers:

It’s worth re-visiting the two key phrases in the OIPC guidance, which are:

Tokenization is distinct from encryption; while encryption may be deciphered given sufficient computer analysis, tokens cannot be decoded without access to the crosswalk table.

What I take from this is that the OIPC is saying that “encryption” is vulnerable (it “may be deciphered”), and “tokenization” is not (it “cannot be decoded”). Now, as discussed on day 3, the “cannot be decoded” part is only true for a very small sub-set of “tokenization”, the kind that uses fully random tokens. And the OIPC is aware of this, though they only barely acknowledge it:

Public bodies may comply with FIPPA provided that the personal information is adequately tokenized and the crosswalk table is secured in Canada.

If you take “adequately” to mean “adequately” such that “tokens cannot be decoded without access to the crosswalk table” then you’re talking about an extremely restrictive definition of tokenization. A lot more restrictive than what vendors are talking about when they come to sell you tokenization.

The vendors who are phoning me and commenting here are worried that readers will see my critique and think “huh, tokenization is insecure”. And that’s not what I’m saying. What I’m saying is:

Practical use of tokenization in a USA cloud CRM is not consistent with the British Columbia OIPC’s incredibly narrow definition of an acceptable level of data security for personal information stored in foreign jurisdictions or under foreign control.
– Paul Ramsey, Just Now

If you’re just looking for a reasonable level of surety that your data in a cloud service cannot be easily poked and prodded by a third party (or the cloud service itself), and you don’t mind adding the extra level of complexity of interposing a tokenization service/server into your interactions with the cloud service, then by all means, a properly configured tokenization system would seem to fit the bill nicely.