Re: which hash function is secure?

cranium.2003_at_gmail.com
Date: 05/28/05

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    Date: 28 May 2005 09:45:54 -0700

    Unruh wrote:
    > cranium.2003@gmail.com writes:
    >
    > >hello,
    > > On http://en.wikipedia.org/wiki/Hash_function its given that=>
    > > The MD5 and SHA-1 algorithms are two popular but compromised
    > >algorithms for generating cryptographic hash functions; the SHA-2
    > >algorithm has no known compromises.
    > > Then does that mean MD5 and SHA-1 are not one way that mean they
    > >can be broken down?
    > They are one way. They are still hashes. They are just not as
    > cryptographically secure as would be wanted. Ie, it is possible to find two
    > pieces of text which have the same hash in far fewer operations than should
    > be the case. It has not AFAIK been shown that one can find a second text
    > which has the same hash as a given text (the authentication use), but means
    > that you can find two pieces of input that have the same hash. It may mean
    > that for example youcould easily find garbage1 and garbage 2 such that
    > Text1+hidden garbage1 has the same hash as Text2+hidden garbage2. This
    > would allow you to send joe bloggs Text1(+hidden garbage1) as the text of a
    > contract, and later go to court with Text2(+hidden garbage2) as the text of
    > the contract. Since Text2 would match the hash, you might convince a court
    > that Text2 was the contact rather than Text1.
    >

              Which is best MD5 or SHA-1? What are pros and cons of each
    others?
    > >regards,
    > >cranium

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