Doc #78628 [Com]: AES-256-XTS cipher method does not work

Edit report at https://bugs.php.net/bug.php?id=78628&edit=1

 ID:                 78628
 Comment by:         alisauxbpdsn53 at gmail dot com
 Reported by:        [email protected]
 Summary:            AES-256-XTS cipher method does not work
 Status:             Open
 Type:               Documentation Problem
 Package:            OpenSSL related
 Operating System:   Linux
 PHP Version:        7.3.10
 Block user comment: N
 Private report:     N

 New Comment:

That was so amazing. 

(https://www.kohlsfeedback.org/)github.com


Previous Comments:
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[2019-12-08 18:47:11] [email protected]

Yeah I think this is more documentation issue. Some ciphers require different handling so we shouldn't state that "penssl_encrypt() accepts methods returned from openssl_get_cipher_methods()". In a similar way chacha20-poly1305 doesn't work as AEAD - requested in https://bugs.php.net/bug.php?id=76935 .

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[2019-12-02 09:07:02] [email protected]

I don't really have a use-case, but documentation says that openssl_encrypt() accepts methods returned from openssl_get_cipher_methods(). No mention about some being not implemented or buggy.

The function throws E_WARNING in some cases, maybe that's another case for E_WARNING. Or maybe you have to just make it working.

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[2019-12-01 19:44:59] [email protected]

I think XTS needs a bit more handling so it's not fully supported. We could change this to the request to add support for it but wondering what the actual use case for XTS is in PHP world? It's mainly meant for disk encryption from what I know about this mode.

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[2019-10-04 11:06:27] [email protected]

Additional info:
$ openssl list -cipher-algorithms | grep XTS
AES-128-XTS
AES-256-XTS

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[2019-10-03 11:10:13] [email protected]

Description:
------------
Tested with various PHP versions (7.3.9 and 7.4.0beta4 and some older 7.x) on Ubuntu 18.04. This originates from on of our users using PHP 7.3 on Debian Stable.

$php -r "print_r(openssl_get_cipher_methods());" | grep -i xts
    [12] => aes-128-xts
    [35] => aes-256-xts

However, if you see the test script openssl_enrypt() does not work, returns false. No error/warning. The same for AES-128-XTS.

I'm not sure what is expected from OpenSSL in the system, but `openssl ciphers -v | grep XTS` returns nothing.

Maybe that's not a bug, but I'd like to hear some explanation for this behavior.

Test script:
---------------
$iv = random_bytes(openssl_cipher_iv_length("aes-256-XTS"));
echo openssl_encrypt("test", "aes-256-XTS", "key", OPENSSL_RAW_DATA, $iv) === false;

Expected result:
----------------
0

Actual result:
--------------
1


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Edit this bug report at https://bugs.php.net/bug.php?id=78628&edit=1