This seems to me to be a client display filter, applied at the last moment as data are streaming back to the client. It has no impact on any keys, queries or secondary internal index or materialized view. It simply prevents the display from showing the complete value. It does not preclude determining what some values are by building carefully crafted queries.
On Wed, Aug 24, 2022 at 8:40 AM Benedict <bened...@apache.org> wrote: > Is it typical for a masking feature to make no effort to prevent > unmasking? I’m just struggling to see the value of this without such > mechanisms. Otherwise it’s just a default formatter, and we should consider > renaming the feature IMO > > On 23 Aug 2022, at 21:27, Andrés de la Peña <adelap...@apache.org> wrote: > > > As mentioned in the CEP document, dynamic data masking doesn't try to > prevent malicious users with SELECT permissions to indirectly guess the > real value of the masked value. This can easily be done by just trying > values on the WHERE clause of SELECT queries. DDM would not be a > replacement for proper column-level permissions. > > The data served by the database is usually consumed by applications that > present this data to end users. These end users are not necessarily the > users directly connecting to the database. With DDM, it would be easy for > applications to mask sensitive data that is going to be consumed by the end > users. However, the users directly connecting to the database should be > trusted, provided that they have the right SELECT permissions. > > In other words, DDM doesn't directly protect the data, but it eases the > production of protected data. > > Said that, we could later go one step ahead and add a way to prevent > untrusted users from inferring the masked data. That could be done adding a > new permission required to use certain columns on WHERE clauses, different > to the current SELECT permission. That would play especially well with > column-level permissions, which is something that we still have pending. > > On Tue, 23 Aug 2022 at 19:13, Aaron Ploetz <aaronplo...@gmail.com> wrote: > >> Applying this should prevent querying on a field, else you could leak its >>> contents, surely? >>> >> >> In theory, yes. Although I could see folks doing something like this: >> >> SELECT COUNT(*) FROM patients >> WHERE year_of_birth = 2002 >> AND date_of_birth >= '2002-04-01' >> AND date_of_birth < '2002-11-01'; >> >> In this case, the rows containing the masked key column(s) could be >> filtered on without revealing the actual data. But again, that's probably >> better for a "phase 2" of the implementation. >> >> Agreed on not being a queryable field. That would also preclude secondary >>> indexing, right? >> >> >> Yes, that's my thought as well. >> >> On Tue, Aug 23, 2022 at 12:42 PM Derek Chen-Becker <de...@chen-becker.org> >> wrote: >> >>> Agreed on not being a queryable field. That would also preclude >>> secondary indexing, right? >>> >>> On Tue, Aug 23, 2022 at 11:20 AM Benedict <bened...@apache.org> wrote: >>> >>>> Applying this should prevent querying on a field, else you could leak >>>> its contents, surely? This pretty much prohibits using it in a clustering >>>> key, and a partition key with the ordered partitioner - but probably also a >>>> hashed partitioner since we do not use a cryptographic hash and the hash >>>> function is well defined. >>>> >>>> We probably also need to ensure that any ALLOW FILTERING queries on >>>> such a field are disabled. >>>> >>>> Plausibly the data could be cryptographically jumbled before using it >>>> in a primary key component (or permitting filtering), but it is probably >>>> easier and safer to exclude for now… >>>> >>>> On 23 Aug 2022, at 18:13, Aaron Ploetz <aaronplo...@gmail.com> wrote: >>>> >>>> >>>> Some thoughts on this one: >>>> >>>> In a prior job, we'd give app teams access to a single keyspace, and >>>> two roles: a read-write role and a read-only role. In some cases, a >>>> "privileged" application role was also requested. Depending on the >>>> requirements, I could see the UNMASK permission being applied to the RW or >>>> privileged roles. But if there's a problem on the table and the operators >>>> go in to investigate, they will likely use a SUPERUSER account, and they'll >>>> see that data. >>>> >>>> How hard would it be for SUPERUSERs to *not* automatically get the >>>> UNMASK permission? >>>> >>>> I'll also echo the concerns around masking primary key components. >>>> It's highly likely that certain personal data properties would be used as a >>>> partition or clustering key (ex: range query for people born within a >>>> certain timeframe). In addition to the "breaks existing" concern, I'm >>>> curious about the challenges around getting that to work with the current >>>> primary key implementation. >>>> >>>> Does this first implementation only apply to payload (non-key) >>>> columns? The examples in the CEP currently do not show primary key >>>> components being masked. >>>> >>>> Thanks, >>>> >>>> Aaron >>>> >>>> >>>> On Tue, Aug 23, 2022 at 6:44 AM Henrik Ingo <henrik.i...@datastax.com> >>>> wrote: >>>> >>>>> On Tue, Aug 23, 2022 at 1:10 PM Andrés de la Peña < >>>>> adelap...@apache.org> wrote: >>>>> >>>>>> One thought: The way the CEP is currently written, it is only >>>>>>> possible to mask a column one way. You can only define one masking >>>>>>> function >>>>>>> for a column, and since you use the original column name, you could only >>>>>>> return one version of it in the result set, even if you had a way to >>>>>>> define >>>>>>> several functions. >>>>>>> >>>>>> >>>>>> Right, it's one single type of mapping per the column, declared on >>>>>> CREATE/ALTER TABLE statements. Also, users can manually specify their own >>>>>> masking function in SELECT statements if they have permissions for seeing >>>>>> the clear data. >>>>>> >>>>>> For those cases where the data is automatically masked for an >>>>>> unprivileged user, I don't see the use of including different types of >>>>>> masking for the same column into the same result set. Instead, we might >>>>>> be >>>>>> interested on having different types of masking associated to different >>>>>> roles. We could do so with dedicated CREATE/DROP/LIST MASK statements, >>>>>> instead of using the CREATE/ALTER/DESCRIBE TABLE statements. That CREATE >>>>>> MASK statement would associate a masking function to a column and role. >>>>>> However, I'm not sure we need that type of granularity instead of the >>>>>> simplicity of attaching the masking to the column declaration. wdyt? >>>>>> >>>>>> >>>>>> >>>>> My gut feeling likewise is that this adds complexity but little value. >>>>> >>>>>> >>>>>>> >>>>> >>>>> -- >>>>> >>>>> Henrik Ingo >>>>> >>>>> +358 40 569 7354 <358405697354> >>>>> >>>>> [image: Visit us online.] <https://www.datastax.com/> [image: Visit >>>>> us on Twitter.] <https://twitter.com/DataStaxEng> [image: Visit us >>>>> on YouTube.] >>>>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.youtube.com_channel_UCqA6zOSMpQ55vvguq4Y0jAg&d=DwMFaQ&c=adz96Xi0w1RHqtPMowiL2g&r=IFj3MdIKYLLXIUhYdUGB0cTzTlxyCb7_VUmICBaYilU&m=bmIfaie9O3fWJAu6lESvWj3HajV4VFwgwgVuKmxKZmE&s=16sY48_kvIb7sRQORknZrr3V8iLTfemFKbMVNZhdwgw&e=> >>>>> [image: Visit my LinkedIn profile.] >>>>> <https://www.linkedin.com/in/heingo/> >>>>> >>>> >>> >>> -- >>> +---------------------------------------------------------------+ >>> | Derek Chen-Becker | >>> | GPG Key available at https://keybase.io/dchenbecker and | >>> | https://pgp.mit.edu/pks/lookup?search=derek%40chen-becker.org | >>> | Fngrprnt: EB8A 6480 F0A3 C8EB C1E7 7F42 AFC5 AFEE 96E4 6ACC | >>> +---------------------------------------------------------------+ >>> >>>
