Re: Hash functions and streaming

From: Volker Birk (bumens_at_dingens.org)
Date: 10/30/05 

Date: 30 Oct 2005 15:02:31 +0200

Lassi Hippeläinen <lahippel.at.ieee.org@moon.invalid> wrote:
> > I have the following scenario:
> > I have a continuous audio stream of data blocks passing from a server
> > to a client.
> > Each block is unencrypted but contains a message digest (hash) of that
> > block using SHA-1. The message digest is encrypted using RSA with a
> > private key, creating a digital signature.
> > At the client side, the public key is used to decrypt the message
> > digest.
> > The data block is hashed to produce another message digest.
> > The two digests are compared to see if they match.
> > If they do, the data block is accepted. If they do not the data block
> > is rejected.
> You have two layers of cryptography, hash and encryption. In your case the
> break of SHA-1 shouldn't be relevant.

This is wrong.

Yours,
VB. 

-- 
"Ich bin ein freier Mensch und werde jetzt von meinen Freiheitsrechten
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                   Wolfgang Clement am 10.10.05 als Noch-Superminister