Cryptography

If an attacker could change the data of a block on a blockchain, recalculate its hash value, and recalculate the hash values of all the following blocks, what will happen in this case? * Review this lesson to answer the question: http://bit.ly/2ubNcg.4 The change will be accepted and reflected to all blockchain copies that other users of this blockchain have The change will be accepted and reflected only to the copy that the attacker changed The change won't be accepted until more than 50% of the users who use that blockchain approve that, if they do, the change will be accepted and reflected to all blockchain copies, otherwise itll be rejected. None of the above Consider this technique: A computer that wants to make changes to a blockchain must solve a complex mathematical problem first, then it'll be allowed to make changes. Which of the following terms matches the definition of the above technique? Review this lesson to answer the question: http://bit.ly/2ubNcg4 Hashing Proof of work Genesis block Encryption We have a class called HomeAppliance WashingMachine class inherits from HomeAppliance. Both classes have a method called turnOn. Both methods have the same signature and print a statement. HomeAppliance method prints: "Entrance is opened", while WashingMachine method prints: "Washing is started". If we define an object as HomeAppliance appliance WashingMachine 0. Then, we call turnOn on that object, what statement will be printed?* Entrance is opened Washing is started Entrance is opened will be printed first then Washing is started Washing is started will be printed first thern Entrance is opened What differentiates Dictionary data structure from Array data structure?* Both arrays and dictionaries have predefined fixed size Array stores elements and link them to indices, while dictionary stores values and link them to keys Both of the above are correct None of the above is correct We have a class called Car, which has the properties color and modelName. It has two methods, getColor and getModelName. There is a class called TaxiCar that inherits from car. What's correct about TaxiCar class? * It has the same properties of Car but it can't add new properties to them It has the same properties and methods of Car and it can add new properties and new methods, but it can't customize the methods inherited from Car It has the same properties and methods of Car and it can add new properties, add new methods, and it can customize the methods inherited from Car None of the above