Password-based cryptography Password-based cryptography Password-based cryptography generally refers to two distinct classes of methods: Some systems attempt to derive a cryptographic key directly from a password. However, such practice is generally ill-advised when there is a threat of brute-force attack. Techniques to mitigate such attack include passphrases and iterated (deliberately slow) password-based key derivation functions such as PBKDF2 (RFC 2898). Password-authenticated key agreement systems allow two or more parties that agree on a password (or password-related data) to derive shared keys without exposing the password or keys to network attack. Earlier generations of challenge-response authentication systems have also been used with passwords,
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.