Am 12.12.16 um 16:26 schrieb Sammy Kaye Powers:
> Hey internals!
>
> As pointed out in Paragon's excellent blog post,
> openssl_public_encrypt() & openssl_private_decrypt() defaults to the
> insecure OPENSSL_PKCS1_PADDING constant.
>
> https://paragonie.com/blog/2016/12/everything-you-know-about-public-key-encryption-in-php-is-wrong#php-openssl-rsa-bad-default
>
> What are your thoughts about deprecating OPENSSL_PKCS1_PADDING and
> using OPENSSL_PKCS1_OAEP_PADDING as the new default?
Is that backwards compatible? I'm thinking of decrypting data that was
encrypted with the "old" settings...
I just tested this:
<?php
openssl_public_encrypt('Testdata', $crypted, $pubKey,
OPENSSL_PKCS1_OAEP_PADDING);
openssl_private_decrypt($crypted, $decrypt, $privateKey));
var_Dump($decrypt);
// NULL
while this works as expected:
<?php
openssl_public_encrypt('Testdata', $crypted, $pubKey,
OPENSSL_PKCS1_OAEP_PADDING);
openssl_private_decrypt($crypted, $decrypt, $privateKey,
OPENSSL_PKCS1_OAEP_PADDING));
var_Dump($decrypt);
// string(8) "Testdata"
So it looks like you're out of luck with your already encrypted data
when the default-padding is changed. And I suppose that those that used
the default aren't aware of that information being a vital part.
And on a first glance I couldn't find a way of retrieving the used
padding from the data. So there might be no way of retrieving that
information other than by guessing/decrypting using all possible
paddings until a valid value is returned...
Just my 0.02 €
Cheers
Andreas
--
,,,
(o o)
+---------------------------------------------------------ooO-(_)-Ooo-+
| Andreas Heigl |
| mailto:andreas@heigl.org N 50°22'59.5" E 08°23'58" |
| http://andreas.heigl.org http://hei.gl/wiFKy7 |
+---------------------------------------------------------------------+
| http://hei.gl/root-ca |
+---------------------------------------------------------------------+
