Bitcoin Intellectual Property Threats Are any known threats related to Bitcoin intellectual property?

(While unlikely, I guess one long shot threat is that one or more governments would ban the use of the technology.)
According to our good friend Wikipedia (my emphasis): 


  Intellectual property (IP) is a term referring to a number of distinct
  types of creations of the mind for which a set of exclusive rights are
  recognized—and the corresponding fields of law.1 Under intellectual
  property law, owners are granted certain exclusive rights to a variety
  of intangible assets, such as musical, literary, and artistic works;
  discoveries and inventions; and words, phrases, symbols, and designs.
  Common types of intellectual property rights include copyrights,
  trademarks, patents, industrial design rights and trade secrets in
  some jurisdictions.


So to attack Bitcoin you'd need to produce evidence that someone else got there first, or that Bitcoin is mis-using an existing technology beyond it's remit (breaking terms of a license for example). 

This would be hard given the unique nature of Bitcoin, the open source license it was released under (MIT - a very permissive license) and the well-established cryptographic protocols and algorithms it uses (SHA-256, RIPEMD-160, elliptic curve DSA) all of which are taken from worldwide standards (think IEEE, ISO, FIPS etc).

However, I am not a lawyer, and the law varies across the world. It may be possible through some convoluted mechanism to attack it and lay claim to a patent of some kind, but it would take obvious collusion on behalf of the respective court of law to ratify it which may serve to discredit the attacker.