Now From Bruce Schneier, the Skein Hash Function

An anonymous reader writes "Bruce Schneier and company have created a new hash function called Skein. From his blog entry: 'NIST is holding a competition to replace the SHA family of hash functions, which have been increasingly under attack. (I wrote about an early NIST hash workshop here.) Skein is our submission (myself and seven others: Niels Ferguson, Stefan Lucks, Doug Whiting, Mihir Bellare, Tadayoshi Kohno, Jon Callas, and Jesse Walker). Here's the paper."

Comments

Re:Good to see Bruce back

[ShieldW0lf]

From the article:

One-way hash functions are supposed to have two properties. One, they're one way. This means that it is easy to take a message and compute the hash value, but it's impossible to take a hash value and recreate the original message. (By "impossible" I mean "can't be done in any reasonable amount of time.") Two, they're collision free. This means that it is impossible to find two messages that hash to the same hash value.

This is funny. These two properties, discounting the redefinition of impossible, are mutually exclusive. If each message hashes to a unique value, and there are no collisions, then recreating the original message from the hash is as simple as putting a million monkeys to work writing a million works of gibberish and store the hash and gibberish in a dictionary. If you instructed your monkeys to start from the smallest works of gibberish and work towards the longer works, your dictionary would be complete for any message whose length is equal to or less than the longest message in the dictionary.

So basically, this would mean a large number of the worlds finest mathematicians are working tirelessly to create something that is by definition mathematically impossible.