Questions regarding bitcoin as a crypto currency blockchain class! (Please answer this only if you know exactly what this is about!)

1) (2 points) Read the following text carefully, it is in regards to bitcoin as a cryptocurrency and then answer the questions:

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Multi-sig Recall multi-sig from Chapter 3. Lets you keep shares apart, approve transaction without reconstructing key at any point. Instead of taking a single key and splitting it, Bitcoin script directly allows you to stipulate that control over an address be split between different keys. These keys can then be stored in different locations and the signatures produced separately. signed transaction will be constructed on some device, but even if the adversary controls this device, all that he can do is to prevent it from being broadcast to the network. He cant produce valid multi-signatures of some other transaction without the involvement of the other devices.

Example Andrew, Arvind, Ed, and Joseph are co-workers. Their company has lots of Bitcoins. Each of the four generates a key-pair, Each puts one secret key in a safe, private, offline place, but separately. The companys cold-stored coins use multi-sig, so that three of the four keys must sign to release a coin.

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-For the above example, why requiring 3 out of 4, not 4 out of 4, not 2 out of 4? -More generally, why Multi-sig requires k out of n, not n out of n?

2) (1 point) Search and find a list of popular online cryptocurrency wallets and exchanges other than what we introduced in class. Pick the one that interests you the most and introduce to the class.

3) (1 point)) What merchants that you often use accept cryptocurrencies as a payment? Search, find out some of them and introduce to the class.