mcrypt_enc_get_iv_size not working

[Jon Slaughter]

mcrypt_enc_get_ iv_size is not randomizing the vector. I have tried to
randomize the seed in various ways but it always returns the same output.

My current code as follows:

for($i = 1; $i < 5; $i++)
{
list($usec, $sec) = explode(' ', microtime());
srand((float) $sec + ((float) $usec * 100000));

$iv = mcrypt_create_i v(mcrypt_enc_ge t_iv_size($this->CryptRes),
MCRYPT_RAND);
echo $iv."<br/>\n";
}

It outputs the same string each time.


Any ideas?

Thanks,
Jon

[Jon Slaughter]

Re: mcrypt_enc_get_ iv_size not working

Of course I meant mcrypt_create_i v...

[C.]

Re: mcrypt_enc_get_ iv_size not working

On 31 May, 19:27, "Jon Slaughter" <Jon_Slaugh...@ Hotmail.comwrot e:

Of course I meant mcrypt_create_i v...

Code looks OK.

Are you getting a sensible value for mcrypt_enc_get_ iv_size($this-

>CryptRes) ?

Have you tried using the devices as an entropy source?

IIRC mcrypt uses binary strings, in some cases it even assigns C
strings to PHP strings; it might be a better idea to encode the output
before writing to the console/browser:

echo base64_encode($ iv) ."<br/>\n";

C.

[Jon Slaughter]

Re: mcrypt_enc_get_ iv_size not working


"C." <colin.mckinnon @gmail.comwrote in message
news:1180647949 .867403.167430@ o5g2000hsb.goog legroups.com...

On 31 May, 19:27, "Jon Slaughter" <Jon_Slaugh...@ Hotmail.comwrot e:

>Of course I meant mcrypt_create_i v...

>
Code looks OK.
>
Are you getting a sensible value for mcrypt_enc_get_ iv_size($this-

>>CryptRes) ?

>

yeah, its a bug in mcrypt and I randomized the string it returned myself.

Have you tried using the devices as an entropy source?
>
IIRC mcrypt uses binary strings, in some cases it even assigns C
strings to PHP strings; it might be a better idea to encode the output
before writing to the console/browser:
>
echo base64_encode($ iv) ."<br/>\n";
>

Well, it was just for a test.. in reality there is no writing to the
console. Was just trying to figure why my strings were not being randomized.

Thanks,
Jon