Password strength too difficult to remember may be forgotten and so are more likely to be written on paper, which some consider a security risk. In contrast, others argue that forcing users to remember passwords without assistance can only accommodate weak passwords, and thus poses a greater security risk. According to Bruce Schneier, most people are good at securing their wallets or purses, which is a "great place" to store a written password. The minimum number of bits of entropy needed for a password depends on the threat model for the given application. If key stretching is not used, passwords with more
Most recent common ancestor all of the modern population. Due to pedigree collapse, modern individuals may still exhibit clustering, due to vastly different contributions from each of ancestral population . Most recent common ancestor In biology and genealogy, the most recent common ancestor (MRCA, also last common ancestor (LCA), or concestor) of any set of organisms is the most recent individual from which all the organisms are directly descended. The term is also used in reference to the ancestry of groups of genes (haplotypes) rather than organisms. The MRCA of a set of individuals can sometimes be determined by referring to an established pedigree.