There have also been attacks proposed against reduced-round versions of the cipher, that is, versions of DES with fewer than 16 rounds. Such analysis gives an insight into how many rounds are needed for safety, and how much of a "security margin" the full version retains. Differential-linear cryptanalysis was proposed by Langford and Hellman in 1994, and combines differential and linear cryptanalysis into a single attack. An enhanced version of the attack can break 9-round DES with 2 chosen plaintexts and has a 2 time complexity (Biham and others, 2002).
“Foreign born” refers to persons born outside of the United States to parents neither of whom was a . citizen. Foreign born also refers to those born in Puerto Rico. Although individuals born in Puerto Rico are . citizens by birth, they are included among the foreign born because they are born into a Spanish-dominant culture and because on many points their attitudes, views and beliefs are much closer to Hispanics born abroad than to Latinos born in the 50 states or the District of Columbia, even those who identify themselves as being of Puerto Rican origin.