Combinatorial explosion is sometimes used to justify the intractability of certain problems. The decisional composite residuosity assumption is the intractability hypothesis upon which this cryptosystem is based. It was the first book exclusively on the theory of NP-completeness and computational intractability. Public-key cryptography is based on the intractability of certain mathematical problems. Problems like intractability and commonsense knowledge seemed much more immediate and serious. However, there are no known unconditional intractability results or results showing NP-hardness of TFNP problems. Rational agents will then satisfice that intractability by seeking outcomes that produce the maximum utility. However, political intractability led to the dissolution of the Mali Federation in August 1960.