There are different legislations,legal precedents,and theories in German,Japan and China as to whether fraud of paying property or estate for illegal reasons constitutes crime of fraud or not.

The Legal Scope of Civil Fraud;

System design of avoiding credit card fraud;

The design and implementation of an anti-fraud system of telecom;

This paper refutes the standpoint that consumer who knowing the commodity is fake and still buying it will not be protected by law of consumer,through following aspects such as defining consumer concept newly 、cheat of important condition、legislation purpose etc.

Economic information cheating behavior exists in general.

It is able to prevent adversaries from getting the secret and efficiently guard against cheating among participants.

Dynamic secure secret sharing scheme among weighted participants to prevent cheating;

A vector space secret sharing scheme against cheating;

A vector space secret sharing scheme against cheating was proposed for extending the normal threshold structure.

Such constructed codes can meet the bounds for existent codes and have unequal authentication protection (probability of deception) desired.

The author thinks that the distinction between double insurance deception and well-meaning double insurance lies in that the policy holder has the intention of getting inappropriate benefit when making the insurance contract,or the policy holder does not inform the fact though he knows the existence of double insurance or gives a false notice.

This thesis demonstrates carefully the definition and classifications on deceptions of the letter of credit .

Using the Theory of Lemon Market and Game Theory, the authors analyzes the tourism market in China and argues that the information asymmetry and one-time game playing, which derive from the characteristics of the market, are the main environmental causes of deceit.