o Example Cryptanalysis given ciphertext UZQSOVUOHXMOPVGPOZPEVSGZWSZOPFPESXUDBMETSXAIZ VUEPHZHMDZ SHZOWSFPAPPDTSVPQUZWYMXUZUHSX EPYEPOPDZSZUFPOMBZWPFUPZHMDJUDTMOHMQ count relative letter frequencies(see text) guess P&z are e and t guess ZW is th and hence ZWP is the proceeding with trial and error finally get it was disclosed yesterday that several informal but direct contacts have been made with political representatives of the vietcong in moscow 8 復大辱软件学院 LiJTLiJT 8 Example Cryptanalysis • given ciphertext: UZQSOVUOHXMOPVGPOZPEVSGZWSZOPFPESXUDBMETSXAIZ VUEPHZHMDZSHZOWSFPAPPDTSVPQUZWYMXUZUHSX EPYEPOPDZSZUFPOMBZWPFUPZHMDJUDTMOHMQ • count relative letter frequencies (see text) • guess P & Z are e and t • guess ZW is th and hence ZWP is the • proceeding with trial and error finally get: it was disclosed yesterday that several informal but direct contacts have been made with political representatives of the vietcong in moscow