Re: Transparent Data Encryption (TDE) and encrypted files

On Fri, Oct 04, 2019 at 04:58:14PM -0400, Bruce Momjian wrote:
>On Fri, Oct 4, 2019 at 10:46:57PM +0200, Tomas Vondra wrote:
>> Oracle also has a handy "TDE best practices" document [2], which says
>> when to use column-level encryption - let me quote a couple of points:
>>
>> * Location of sensitive information is known
>>
>> * Less than 5% of all application columns are encryption candidates
>>
>> * Encryption candidates are not foreign-key columns
>>
>> * Indexes over encryption candidates are normal B-tree indexes (this
>> also means no support for indexes on expressions, and likely partial
>> indexes)
>>
>> * No support from hardware crypto acceleration.
>
>Aren't all modern systems going to have hardware crypto acceleration,
>i.e., AES-NI CPU extensions. Does that mean there is no value of
>partial encryption on such systems? Looking at the overhead numbers I
>have seen for AES-NI-enabled systems, I believe it.
>

That's a good question, I don't know the answer. You're right most
systems have CPUs with AES-NI these days, and I'm not sure why the
column encryption does not leverage that.

Maybe it's because column encryption has to encrypt/decrypt much smaller
chunks of data, and AES-NI is not efficient for that? I don't know.

regards

--
Tomas Vondra http://www.2ndQuadrant.com
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