[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,amprenta va iesi la iveala
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,la fiecare a 5-a litera
Dialogue: 0,0:00:04.95,0:00:08.16,Default,,0000,0000,0000,,Un cod puternic este acela care deghizeaza amprenta limbii
Dialogue: 0,0:00:08.96,0:00:10.84,Default,,0000,0000,0000,,Pentru a face o amprenta mai usoara
Dialogue: 0,0:00:10.84,0:00:14.27,Default,,0000,0000,0000,,trebuie sa distribuim frecventa aparitii literelor
Dialogue: 0,0:00:17.60,0:00:18.94,Default,,0000,0000,0000,,In mijlocul secolului al 15-lea
Dialogue: 0,0:00:18.94,0:00:21.27,Default,,0000,0000,0000,,am avansat la coduri polialfabetice
Dialogue: 0,0:00:21.27,0:00:23.36,Default,,0000,0000,0000,,pentru a realiza asta
Dialogue: 0,0:00:23.36,0:00:28.17,Default,,0000,0000,0000,,Imaginati-va ca Alice si Bob au un cuvant secret cu ajutorul caruia muta literele
Dialogue: 0,0:00:28.17,0:00:30.77,Default,,0000,0000,0000,,Prima data Alice schimba cuvintele in cifre
Dialogue: 0,0:00:30.77,0:00:33.22,Default,,0000,0000,0000,,coresponzand cu pozitia literelor respective in alfabet
Dialogue: 0,0:00:33.22,0:00:37.83,Default,,0000,0000,0000,,Apoi, aceasta secventa de numere este repetata prin mesaj
Dialogue: 0,0:00:39.48,0:00:41.98,Default,,0000,0000,0000,,Apoi, fiecare litera din mesaj este encriptata prin mutarea
Dialogue: 0,0:00:41.98,0:00:44.16,Default,,0000,0000,0000,,dupa numarul de sub ea
Dialogue: 0,0:00:45.13,0:00:48.81,Default,,0000,0000,0000,,Acum foloseste mai multe feluri de mutari in loc de una singura
Dialogue: 0,0:00:48.81,0:00:53.64,Default,,0000,0000,0000,,pe parcursul mesajului, asa cum facea Caesar mai de mult.
Dialogue: 0,0:00:53.64,0:00:56.63,Default,,0000,0000,0000,,Apoi, mesajul encriptat este trimis lui Bob
Dialogue: 0,0:00:58.49,0:01:01.63,Default,,0000,0000,0000,,Bob decripteaza acest mesaj prin scaderea numarului de mutari
Dialogue: 0,0:01:01.63,0:01:04.86,Default,,0000,0000,0000,,dupa cuvantul secret pe care il cunoaste si el
Dialogue: 0,0:01:06.12,0:01:08.04,Default,,0000,0000,0000,,Acum imaginati-va ca Eve intercepteaza acest cod, si incearca sa il sparga
Dialogue: 0,0:01:10.17,0:01:12.64,Default,,0000,0000,0000,,si calculeaza frecventele literelor.
Dialogue: 0,0:01:13.67,0:01:18.04,Default,,0000,0000,0000,,O sa gaseasca o distributie mai usoara a literelor, o amprenta mai vaga
Dialogue: 0,0:01:18.04,0:01:20.59,Default,,0000,0000,0000,,Deci cum ar putea sa-l sparga?
Dialogue: 0,0:01:22.55,0:01:26.17,Default,,0000,0000,0000,,Desigur, spargatorii de coduri cauta scurgeri de informatii,
Dialogue: 0,0:01:26.17,0:01:29.38,Default,,0000,0000,0000,,acelasi lucru ca si gasirea unei amprente partiale
Dialogue: 0,0:01:29.38,0:01:32.41,Default,,0000,0000,0000,,Oricand exista o diferenta intre frecventele dintre litere
Dialogue: 0,0:01:32.41,0:01:34.93,Default,,0000,0000,0000,,exista o scurgere in informatii
Dialogue: 0,0:01:36.13,0:01:39.83,Default,,0000,0000,0000,,Diferenta este cauzata de repetitia in mesajul encriptat
Dialogue: 0,0:01:41.70,0:01:45.91,Default,,0000,0000,0000,,In acest caz, codul lui Alice contine un cuvant care se repeta
Dialogue: 0,0:01:47.22,0:01:51.10,Default,,0000,0000,0000,,Pentru a sparge encriptarea, Eve trebuie mai intai sa determine
Dialogue: 0,0:01:51.10,0:01:55.57,Default,,0000,0000,0000,,lungimea cuvantului folosit pentru a muta, si nu cuvantul.
Dialogue: 0,0:01:55.57,0:01:56.92,Default,,0000,0000,0000,,Ea trebuie sa verifice frecventa
Dialogue: 0,0:01:56.92,0:02:00.49,Default,,0000,0000,0000,,distributiei la intervale diferite
Dialogue: 0,0:02:00.49,0:02:04.43,Default,,0000,0000,0000,,Cand verifica frecventa distributiei
Dialogue: 0,0:02:07.65,0:02:10.14,Default,,0000,0000,0000,,Problema acum, este sa sparga codul lui Caesar
Dialogue: 0,0:02:10.14,0:02:12.82,Default,,0000,0000,0000,,intr-o secventa care se repeta
Dialogue: 0,0:02:12.82,0:02:14.73,Default,,0000,0000,0000,,Individual, asta e o sarcina banala
Dialogue: 0,0:02:14.73,0:02:17.14,Default,,0000,0000,0000,,pentru ca, dupa cum am vazut inainte , cat de greu poate fi descifrat un cod
Dialogue: 0,0:02:17.14,0:02:19.74,Default,,0000,0000,0000,,depinde de
Dialogue: 0,0:02:19.74,0:02:22.91,Default,,0000,0000,0000,,lungimea cuvantului care se folosesta pentru a muta literele
Dialogue: 0,0:02:22.91,0:02:26.91,Default,,0000,0000,0000,,Cu cat este mai lung cuvant folosit pentru a muta literele, cu atat este mai puternic codul.