Re: More secure defaults for openssl_public_encrypt() & openssl_private_decrypt()
| From: | Andreas Heigl | Date: | Mon, 12 Dec 2016 16:02:05 +0000 |
| Subject: | Re: More secure defaults for openssl_public_encrypt() & openssl_private_decrypt() | ||
| References: | 1 | Groups: | php.internals |
| Request: | Send a blank email to internals+get-97371@lists.php.net to get a copy of this message | ||
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
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