Making a weak Hash stronger until a fix comes along -- concatenation of hash functions... .2: Concatenation

From: Max Power (mikehack_at_u.washington.edu)
Date: 09/26/05 

Date: Mon, 26 Sep 2005 00:01:16 -0700

My use of concatenation was not totally clear.
I would never consider adding the strings of the 2 hashes together.
I would take the binary output and use it as a binary input into another
hash function.
+
Some checksum, salt or nothing at all.

True, it is not a perfect solution -- but merely an adequate one.

> To answer the original poster's question, no, it's not particularaly
> secure. I can't find it right now, but when this was asked previously,
> someone pointed to a clever proof that concatenating two different
> hashes in the same family (eg, SHA1 and MD5) adds far less security
> than you'd expect - certainly not the 160+128 that casual inspection
> determines.

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