암호학 자료

http://infosec.kut.ac.kr/sangjin/class/cryptoprog0701/note01.pdf

http://infosec.kut.ac.kr/sangjin/class/cryptoalgo2010-01/chap04.pdf

http://marcof.tistory.com/58

http://system.kcu.ac/opendept/crypto/sub/sub04.htm

http://math88.com.ne.kr/crypto/DES/2des.html