RE: Combining MD5 and SHA-1 to reduce collision probability

2011-04-26 Thread Steffen DETTMER
Hi, thank you for clarification, Dave! * Dave Thompson Friday, April 22, 2011 12:34 AM: > > so among 2^n+1 different messages, at least two of them > > must have the > > same 2^n bit hash (actually half because of birthday "attack"). > > To be exact: for an n-bit or 2^n-value hash, with 2^n + 1

Re: Combining MD5 and SHA-1 to reduce collision probability

2011-04-22 Thread Luc Perthuis
Thank you all for your valuable answers. On 22/04/2011 00:33, Dave Thompson wrote: *Accidental* (birthday) collision is about 264 for MD5 and about 280 for SHA-1. > SHA-256 should be much stronger, would this be sufficient > for your needs? Or

RE: Combining MD5 and SHA-1 to reduce collision probability

2011-04-21 Thread Dave Thompson
> From: owner-openssl-us...@openssl.org On Behalf Of Steffen DETTMER > Sent: Wednesday, 20 April, 2011 12:25 > * Luc Perthuis: > > Is there any theoretical proof for a "good" selection of 2 > > HASH (computing the results of two different algorithms on > > the same data) that would annihilate t

RE: Combining MD5 and SHA-1 to reduce collision probability

2011-04-20 Thread Steffen DETTMER
* Luc Perthuis: > Hi all, > > I'm specially interested on finding a way to uniquely > identify rather small data chunks (less than or equal to > 128*1024 bytes in size) without using a byte per byte compare. > > Is there any theoretical proof for a "good" selection of 2 > HASH (computing the re

Re: Combining MD5 and SHA-1 to reduce collision probability

2011-04-20 Thread David Schwartz
On 4/20/2011 1:18 AM, Luc Perthuis wrote: Hi all, I'm specially interested on finding a way to uniquely identify rather small data chunks (less than or equal to 128*1024 bytes in size) without using a byte per byte compare. Is there any theoretical proof for a "good" selection of 2 HASH (comput

Combining MD5 and SHA-1 to reduce collision probability

2011-04-20 Thread Luc Perthuis
Hi all, I'm specially interested on finding a way to uniquely identify rather small data chunks (less than or equal to 128*1024 bytes in size) without using a byte per byte compare. Is there any theoretical proof for a "good" selection of 2 HASH (computing the results of two different algori