AWS terms of service (http://aws.amazon.com/agreement/#4b) "you may not operate a site or service that: ... Distributes, shares, or facilitates the distribution of unauthorized data, malware, viruses, Trojan horses, spyware, worms, or other malicious or harmful code (collectively, “Harmful Components”)." It strikes me that a password-cracking service at least sails very close to the wind in respect of this clause.

You might have a tiny problem with 'prior art'. Even the US Patent Office ought to be convinced by a copy of K&R...