”©海在长 15 More on Symmetric Ciphers "I am fairly familiar with all the forms of secret writings,and am myself the author of a trifling monograph upon the subject,in which I analyze one hundred and sixty separate ciphers,said Holmes. -The Adventure of the Dancing Men,Sir Arthur Conan Doyle 甲A四 2022/10/9 现代密码学理论与实践-06 2/572022/10/9 现代密码学理论与实践-06 2/57 More on Symmetric Ciphers "I am fairly familiar with all the forms of secret writings, and am myself the author of a trifling monograph upon the subject, in which I analyze one hundred and sixty separate ciphers," said Holmes. —The Adventure of the Dancing Men, Sir Arthur Conan Doyle