1) Represent the ownerships and permissions shown in this UNIX directory listing as a protection ma ...

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1) Represent the ownerships and permissions shown in this UNIX directory listing as a protection matrix. (Note: asw is a member of two groups: users and devel; gmw is a member only of users.) Treat each of the two users and two groups as a domain, so that the matrix has four rows (one per domain) and four columns (one per file). – rw– r– – r– – 2 gmw users 908 May 26 16:45 PPP– Notes – rwx r– x r– x 1 asw dev el 432 May 13 12:35 prog1 – rw– rw– – – – 1 asw users 50094 May 30 17:51 project.t – rw– r– – – – – 1 asw dev el 13124 May 31 14:30 splash.gif 2)Suppose that two strangers A and B want to communicate with each other using secretkey cryptography, but do not share a key. Suppose both of them trust a third party C whose public key is well known. How can the two strangers establish a new shared secret key under these circumstances 3). Natural-language text in ASCII can be compressed by at least 50% using various compression algorithms. Using this knowledge, what is the steganographic carrying capacity for ASCII text (in bytes) of a 1600 × 1200 image stored using the low-order bits of each pixel? How much is the image size increased by the use of this technique (assuming no encryption or no expansion due to encryption)? What is the efficiency of the