OT: PHP BCMath slowness

Carl Howells chowells at janrain.com
Thu Aug 4 10:00:51 PDT 2005

Carl Howells wrote:
> Kurt Raschke wrote:
>> I'm working on OpenID producer and consumer support for a PHP-based  
>> content management system, and I am finding that BCMath seems to be  
>> extraordinarily slow for such things as Diffie-Hellman  
>> calculations...what takes BCMath 40-45 seconds is done by GMP in just  
>> a few seconds at most.  I am not sure if it is even wise to include  
>> BCMath support if it is going to over-run PHP's 30-second execution  
>> limit in most cases.
>> Any thoughts?
> All of those numbers look ridiculous.  The math involved for DH 
> calculations is two powermod operations per side of the transaction. 
> With the exponents in the 1024-bit range, that shouldn't take more than 
> about a half-second

Hmm.  I noticed Taral's response, and that it covered everything I 
wanted to say...  So I went to close my message, and then hit "send" 
instead.  Oops.  Sorry I didn't say anything actually useful.


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