On 2019-Jul-27, Sehrope Sarkuni wrote:
> Given the non-cryptographic nature of CRC and its 16-bit size, I'd
> round down the malicious tamper detection it provides to zero. At best
> it catches random disk errors so might as well keep it in plain text
> and checkable offline.
But what attack are we protecting against? We fear that somebody will
steal a disk or a backup. We don't fear that they will *write* data.
The CRC is there to protect against data corruption. So whether or not
the CRC protects against malicious tampering is beside the point.
If we were trying to protect against an attacker having access to
*writing* data in the production server, this encryption scheme is
useless: they could just as well read unencrypted data from shared
buffers anyway.
I think trying to protect against malicious data tampering is a second
step *after* this one is done.
--
Álvaro Herrera https://www.2ndQuadrant.com/
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