... H T 22 11 11 12 4 19 19 12 13 19 - Mó húa cỏc b hai ký t theo h th c mó húa: (y1, y2) = (x1, x2).k 20 11 22 24 24 14 20 23 22 20 11 2 U - Khúa gi i mó s l: (x1, x2) = (y1, y2).k -1 = (y1, y2) ... 13 19 14 19 20 24 14 14 19 24 Ek(x1, x2, , xm) = ( x1 + k1, x2 + k2, , xm + km) (mod 26 ) 12 18 25 21 15 15 16 17 14 18 25 22 Dk(y1, y2, , ym) = ( y1 - k1, y2 - k2, , ym - km) (mod 26 ) J M C A ... 12 13 14 15 16 P : T p h p cỏc b n rừ 17 18 19 20 21 24 25 K L M N O P Q R S T U V W X Y Z 21 F G H F G H 10 11 14 18 19 20 23 24 25 J K L M N O P Q R S T U V W X Y Z A B C D E 13 15 16 22 22 ...