Re: MD5 To Be Considered Harmful Someday

• Previous message: http-equiv_at_excite.com : "Address Bar Spoophing for the Pheeshies: IntotheNet Explorer 6"
• In reply to: Gandalf The White: "Re: MD5 To Be Considered Harmful Someday"
• Next in thread: Steve Friedl: "Re: MD5 To Be Considered Harmful Someday"
• Reply: Steve Friedl: "Re: MD5 To Be Considered Harmful Someday"
• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]

Date: Tue, 7 Dec 2004 18:51:48 -0700 (MST)
To: Gandalf The White <gandalf@digital.net>

On Tue, 7 Dec 2004, Gandalf The White wrote:

> >From my reading it appears that you need the original source to create the
> doppelganger blocks. It also appears that given a MD5 hash you could not
> create a input that would give that MD5 back. Passwords encoded with MD5
> would not fall prey to your discovery. Is this correct?

My understanding is similar to yours.

However, imagine a PKI system in, say, a contract management system.

Let's say you can write a valid word document with a section of text that
can be "swapped" out.

That can be a problem. It breaks non-repudiation - someone could create
such a "swappable" contract and go to court and say "Yes, that's a valid
signature, but I really signed *THIS* document which just happens to have
an identical signature." Of course if I was called upon to testify, I
would respond, "Yes, but it is clear this contract was written with the
intent to defraud us, as to get this property, it has to be constructed in
a very specific mind with this fraud in mind at time of contract
origination..."

-- 
Joel

• Previous message: http-equiv_at_excite.com : "Address Bar Spoophing for the Pheeshies: IntotheNet Explorer 6"
• In reply to: Gandalf The White: "Re: MD5 To Be Considered Harmful Someday"
• Next in thread: Steve Friedl: "Re: MD5 To Be Considered Harmful Someday"
• Reply: Steve Friedl: "Re: MD5 To Be Considered Harmful Someday"
• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]