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McKenzie Andreatta Nathan Ducey Angelo Marchesini Reilly Roach Cryptography Goodies VOCAB Cryptography: the study of the techniques of writing and decoding messages. Plaintext Matrix: The original message once it has been put into numerical and matrix form. Cipher Matrix: the matrix that will allow us to encrypt the message. Also, the cipher matrix must be a square invertible matrix. Encrypting: the process of putting a message into secret code. For us this means multiplying the plaintext matrix by the cipher matrix. Ciphertext Matrix: The result of multiplying the cipher matrix by the plaintext matrix. Decrypting: the process of making the message intelligible again by using the inverse of the cipher matrix and multiplying it by the ciphertext matrix. Steps of Encrypting and Decrypting Encrypting: 1. Choose a nxn matrix to be the cipher matrix and call it A. 2. Write out your message and assemble vectors with n entries. Then, using the vectors as columns, you get a matrix and we will call this P. 3. Assign each letter a number and apply to your matrix (A=1, B=2, etc.) 4. To encrypt, we then multiply AP=C, where C is the ciphertext matrix. Decrypting: 1. Identify the ciphertext matrix. 2. Then determine A-1 (The inverse of the cipher matrix). 3. Multiply A-1C=D, where D is the decrypted matrix. 4. Convert the entries of your decrypted matrix back to text to identify the secret message! A 1 B 2 C 3 D 4 E 5 F 6 G 7 H 8 I 9 J 10 K 11 L 12 M 13 N 14 O 15 P 16 Q 17 R 18 S 19 T 20 U 21 V 22 W 23 X 24 Y 25 Z 26 _ 27