to fit). The alphabets in both squares are generally mixed alphabets, each based on some keyword or phrase. To generate the 5x5 matrices, one would first fill in the spaces in the matrix with the letters of a keyword or phrase (dropping any duplicate letters), then fill the remaining spaces with the rest of the letters of the alphabet in order (again omitting "Q" to reduce the alphabet to fit). The key can be written in the top rows of the table, from left to right, or in some other pattern, such as a spiral beginning in the upper-left-hand corner and ending in the center. The keyword together with the conventions for filling in the 5x5 table constitute the cipher key. The two-square algorithm allows for two separate keys, one for each matrix. As an example, here are the vertical two-square matrices for the keywords "example" and "keyword": E X A M P L B C D F G H I J K N O R S T U V W Y Z K E Y W O R D A B C F G H I J L M N P S T U V X Z Algorithm Encryption using two-square is basically the same as the system used in four-square, except that the plaintext and ciphertext digraphs use the same matrixes. To encrypt a message, one would Follow these steps: Split the payload message into digraphs. (help me obi wan kenobi becomes he lp me ob iw an ke no bi) For a vertical two-square, the first character of both plaintext and ciphertext digraphs uses the top matrix, while the second character uses the bottom. For a horizontal two-square, the first character of both digraphs uses the left matrix, while the second character uses the right. Find the first letter in the digraph in the upper/left text matrix. E X A M P L B C D F G H I J K N O R S T U V W Y Z K E Y W O R D A B C F G H I J L M N P S T U V X Z Find the second letter in the digraph in the lower/right plaintext matrix. E X A M P L B C D F G H I J K N O R S T U V W Y Z K E Y