Re: MD5 is insecure

[Seth David Schoen via NANOG <nanog () lists nanog org>]

brent saner via NANOG writes:

> Alice creates keypair *KP2*, with public key *K2*. Alice then pads
> junk to *K2*'s *n* until she reaches collision in the wire-packed form
> with *C,* creating *Blob1*. Let's say Alice had to add 512 bytes to
> reach collision with *C*.

To "reach collision in the wire-packed form with C", for a value of C
that Alice was given and didn't choose, with currently known techniques,
Alice has to do 2¹²⁸ work, which she can't do.  It's not good practice
to give Alice this attack vector for no reason, and maybe a future
technique could make it more feasible, but it's still not expected that
she can exploit it at present.
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