The death of MD5

[Skywing]

http://lists.grok.org.uk/pipermail/full-disclosure/2005-November/038719.html

Looks like it's time to move anything you have still using MD5 away from it.  45 minutes to generate a collision on a slow P4 is about as broken as you can get, makes it completely useless for any practical purposes now.

[rabbit]

Wow...a post...from Skywing...

Anyways,

Average runtime on P4 1.6ghz - 5 seconds

Damn....but I guess it's still good for a hash of a program, as I assume it would be pretty hard to get executable code (or whatever) to collide with other other executable code.

[Warrior]

* Warrior runs to update his website. !

[Newby]

Wow...

[Blaze]

* Warrior runs to update his website. !

I told you! Now what I thought would happen, actually did.

[Warrior]

Good thing PHP has built in sha1(). I'll have to make everyone resign up though.

Not something top priority however.

[dxoigmn]

Now to see what the experts say about this. I'm surprised there was no discussion for that thread.

[DeTaiLs]

Good thing PHP has built in sha1(). I'll have to make everyone resign up though.

Not something top priority however.

Aint sha1 the structure of MD5 I could be wrong but that is what it says on wiki.

[Topaz]

Wasn't MD5 cracked last year? hm...

[Newby]

Wasn't MD5 cracked last year? hm...

Not with a mechanism for a 45 minute collision...

[Kp]

Wow...a post...from Skywing...

Anyways,

Average runtime on P4 1.6ghz - 5 seconds

Damn....but I guess it's still good for a hash of a program, as I assume it would be pretty hard to get executable code (or whatever) to collide with other other executable code.

No, not at all.  Programs are routinely quite large these days, and it's no trouble at all to pad your .rdata segment with whatever bytes are necessary to get the hash you want.  Failing that, put the colliding bytes into your .text segment and just ensure that the code flow never tries to execute it.

[noob]

It may have been cracked, but that doesn't make it useless. DES is still used after all.

[Yegg]

It may have been cracked, but that doesn't make it useless. DES is still used after all.

It's safer to move onto newer, more advanced hashing algorithm's however.

[iago]

makes it completely useless for any practical purposes now.

I disagree.  As far as I know, there's still no practicle way (without a full brute force) to obtain the original data of MD5 based on the hash.  In other words, it's still safe for storing passwords. 

Good thing PHP has built in sha1(). I'll have to make everyone resign up though.

Not something top priority however.

You're replacing a dead algorithm with a dying algorithm.  Not a good idea :-P

I'd recommend that you start storing the SHA1 of the MD5.  The advantages are:
- Extra layer of security; even though if both are broken then together they're broken, it'll still keep away the riff raff.
- You don't have to make people re-sign up.  Just SHA1() their MD5() hashes. 
But if you're using it to store a password, I still don't think it's an issue.  Odds are, for most passwords, it can be bruteforced with a dictionary attack anyways

[Warrior]

Yea, I thought of that after I posted.