Bug #70744 [Opn]: random_bytes() should not use linc arc4random
Edit report at https://bugs.php.net/bug.php?id=70744&edit=1
ID: 70744
User updated by: fsb at thefsb dot org
Reported by: fsb at thefsb dot org
Summary: random_bytes() should not use linc arc4random
Status: Open
Type: Bug
Package: *Encryption and hash functions
Operating System: All except Windows
PHP Version: 7.0.0RC5
Block user comment: N
Private report: N
New Comment:
CORRECTION: OpenBSD since 5.5 uses ChaCha20.
But random_bytes() use of arc4random_buf() remains unsafe.
Previous Comments:
------------------------------------------------------------------------
[2015-10-19 22:04:57] fsb at thefsb dot org
Description:
------------
ARC4 is known to be unsafe for use either as a stream cipher or a CSPRNG. You can read about it on
Wikipedia and elsewhere.
As far as I can tell, until recently, all implementations of the libc arc4random functions are based
on David Mazieres 1996 implementation of ARC4. In November 2014, NetBSD replaced the cipher
underneath libc's arc4random API with ChaCha20, a modern stream cipher currently considered
safe. But this change hasn't made it into a NetBSD release yet. OS X, FreeBSD and OpenBSD have
not yet incorporated NetBSD's source code change and I don't know if they will. So for the
time being we have to assume that libc arc4random is ARC4 cipher and therefore unsafe.
This code branch should be removed.
https://github.com/php/php-src/blob/php-7.0.0RC5/ext/standard/random.c#L91
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=70744&edit=1
Thread (7 messages)