Cryptography

1. Cryptography A Lecture in CE Freshman Seminar Series: Ten Puzzling Problems in Computer Engineering Cryptography

2. “CEBA YUC YXSENM PDZ SERSESYZ, YXZ QESOZDMZ PEJ XQKPE “ E E E E E MYQGSJSYA, PEJ S’K ECY MQDZ PLCQY YXZ RCDKZD.” , E E E .” PBLZDY ZSEMYZSE ---- --- ------ -- ------- , -- ---- -- --- ----- E E E --------- --- - - --- --- ----- -- ---- - Simple Substitution Ciphers Decipher the following text, which is a quotation from a famous scientist. Clue: Z stands for E “CEBA YUC YXSENM PDZ SERSESYZ, YXZ QESOZDMZ PEJ XQKPE MYQGSJSYA, PEJ S’K ECY MQDZ PLCQY YXZ RCDKZD.” PBLZDY ZSEMYZSE ----------- Cryptography

3. Cryptography

4. Decoding a Key-Based Cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0001020304 0506 070809101112131415161718 19202122232425 Agreed upon secret key: freshman Decipher the coded message and provide a reply to it using the same key Message:B Y E L P E Y B Z I R S T Q 0124041115 042401250817 18 19 16 Secret key:f r e s h m a n f r e s h m 0517041807 120013051704 18 0712 Difference: __________ ____________ __ __ __ Modulo 26 diff.: __________ ____________ __ __ __ Plain text: __________ ____________ __ __ __ Reply:_ _ _ _ _ _ _ _ _ _ _ _ _ _ __________ ____________ __ __ __ Secret key:f r e s h m a n f r e s h m 0517041807 12001305 1704 18 0712 Sum: __________ ____________ __ __ __ Modulo 26 sum: __________ ____________ __ __ __ Cipher text: __________ ____________ __ __ __ Cryptography