On Tue, Aug 6, 2019 at 01:55:38PM -0400, Bruce Momjian wrote:
> CTR mode creates a bit stream for the first 16 bytes with nonce of
> (segment_number, counter = 0), and the next 16 bytes with
> (segment_number, counter = 1), etc. We only XOR using the parts of the
> bit stream we want to use. We don't care what the WAL content is --- we
> just XOR it with the stream with the matching counter for that part of
> the WAL.
The diagram which is part of this section might be helpful:
https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Counter_(CTR)
https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#/media/File:CTR_encryption_2.svg
--
Bruce Momjian <br...@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
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