corruption in encrypted table may be overlooked

use test;

create table t(a varchar(128)) engine=innodb;

create table t1(a varchar(128)) engine=innodb;

insert into t select repeat('a',100);

insert into t1 select repeat('a',100);

SHOW GLOBAL STATUS LIKE 'Innodb_buffer_pool_pages_dirty';

cd data_directory

printf '\xAA\xAA\xAA\xAA' | dd of=test/t.ibd seek=16384 count=4 bs=1 conv=notrunc

170223 09:53:10 [01] Copying ./test/t.ibd to /bkup/test/t.ibd

170223 09:53:10 [01]        ...done

..

170223 09:53:14 completed OK!

> innochecksum dt/test/t.ibd 

InnoDB offline file checksum utility.

Table is uncompressed

Page size is 16384

Fail;  page 1 invalid (fails old style checksum)

innochecksum test/t1.ibd

170223 10:17:22 [01] Copying ./test/t.ibd to /bkup/test/t.ibd

[01] xtrabackup: Database page corruption detected at page 1, retrying...

...

[01] xtrabackup: Error: failed to read page after 10 retries. File ./test/t.ibd seems to be corrupted.

[01] xtrabackup: Error: xtrabackup_copy_datafile() failed.

[01] xtrabackup: Error: failed to copy datafile.

xtrabackup based on MariaDB server 10.1.22-MariaDB Linux (x86_64) 

...

xtrabackup: Error: cannot open ./xtrabackup_checkpoints

xtrabackup: Error: failed to read metadata from './xtrabackup_checkpoints'