Another approach is to actually break the cipher through cryptanalysis ; finding a weakness in the cipher that can be exploited with a complexity less than brute force. The challenge of successfully attacking a cipher is easier of course if the cipher itself is flawed in the first place. There have always been suspicions that interference from the National Security Agency weakened the Data Encryption Standard algorithm , and following revelations from former NSA analyst and contractor Edward Snowden, many believe they have attempted to weaken encryption products and subvert cryptography standards.
There is a presumption in the classic example of a definition that the definiens can be stated. Wittgenstein argued that for some terms this is not the case.  The examples he used include game , number and family . In such cases, he argued, there is no fixed boundary that can be used to provide a definition. Rather, the items are grouped together because of a family resemblance . For terms such as these it is not possible and indeed not necessary to state a definition; rather, one simply comes to understand the use of the term. [b]