Array ( [0] => Array ( [title] => L4AR [link] => https://www.youtube.com/embed/a2eE9jDbecE ) [1] => Array ( [title] => L4BR [link] => https://www.youtube.com/embed/JmEXCYK_LaI ) [2] => Array ( [title] => L4CR [link] => https://www.youtube.com/embed/WA0xQxyCkE0 ) ) 國立清華大學開放式課程OpenCourseWare(NTHU, OCW) - 第4講 Ch.2 Symmetric-key encryption (1)