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Claim Cr28 - 128bit cipher cracked <2020

Category: Science & Technology:Encryption, Factoring bid 6, ask 8, last 7
Owner:0, Bank
Judge:2, Chris Hibbert
created:1995/08/26
due date:2020/01/14

The Claim

A cryptographic key of 128 bits or longer will be broken, by exhaustively searching the keyspace, before 2010 UT. Keys longer than 128 bits, but with less than 128 bits of entropy, do not count (crippled keys). The results and method of the cracking must be made public. This claim makes no attempt to guess what has been done in private by governments or other organizations.

By "exhaustive" or "brute force" search of an N bit key space, I mean the following:

  1. There are 2^N equi-probable decryption keys (1% maximum variation), up to 1% can be unused because of weak keys etc.
  2. The actual key must have been generated randomly or from a strong hash function.
  3. The keys are tested systematically or randomly, noting only whether each key succeed in decrypting the message.
  4. The key must not have been chosen to have any special form designed to make this attack easy (e.g. the key 0000...0001). This is a judgement call.
On average, the correct key should be found after searching half the possible keys. Known plaintext may be used to check the trial encryptions.

Toy ciphers (in the judge's opinion) do not qualify. This is intended to eliminate things like "ROT 13" and simple XOR with a constant. Any modern public cipher used in real security applications should qualify.

IDEA, the symmetrical cipher used by PGP, uses a 128 bit key.

Judge's Statement

The first sentence of the claim text is inconsistent with the short description and the due date. I will treat 2020/1/1 as the effective deadline. 2020/1/14 gives some leeway for judging.

I will judge this claim based on its intent, guided by the details of the wording and discussion on fx-discuss. If there is a conflict between the text and my perception of the claim's intent, I will consult with fx-discuss before rendering a judgement.

The Market

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