Hi! This is not a graded question I just need it for my reviewer. Thanks! 2.Recall that a public-key cryptosystem consists of three functions: A key generator G, an encryption function E, and a decryption function D. Any user, say Alice (A), can use the key generator to generate a key pair (PKA, SKA), in which PKA is Alice’s public key, and SKA is her secret key; she can then publish her name and public key in a directory. Subsequently, anyone who wants to send a private message x to Alice can look up PKA in the directory, compute a ciphertext y ←− E(x, PKA), and send y to Alice over an open line. Only Alice can compute x ←− D(y, SKA), because only she knows the decryption key SKA that corresponds to encryption key PKA. Note that there is no need for a key-distribution center, as there is when one is using a symmetric-key cryptosystem, but there is a need for public-key directories. a) What is a public-key certificate? What is the problem with public-key directories that certificates address? b) In general, public-key cryptosystems are not fast enough for users who need to exchange long streams of traffic. How can they be used in conjunction with symmetric-key cryptosystems, which are faster, in order to send long streams securely?

Computer Networking: A Top-Down Approach (7th Edition)

7th Edition

ISBN:9780133594140

Author:James Kurose, Keith Ross

Publisher:James Kurose, Keith Ross

Chapter1: Computer Networks And The Internet

Section: Chapter Questions

Problem R1RQ: What is the difference between a host and an end system? List several different types of end...

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Hi! This is not a graded question I just need it for my reviewer. Thanks! 2.Recall that a public-key cryptosystem consists of three functions: A key generator G, an encryption function E, and a decryption function D. Any user, say Alice (A), can use the key generator to generate a key pair (PKA, SKA), in which PKA is Alice’s public key, and SKA is her secret key; she can then publish her name and public key in a directory. Subsequently, anyone who wants to send a private message x to Alice can look up PKA in the directory, compute a ciphertext y ←− E(x, PKA), and send y to Alice over an open line. Only Alice can compute x ←− D(y, SKA), because only she knows the decryption key SKA that corresponds to encryption key PKA. Note that there is no need for a key-distribution center, as there is when one is using a symmetric-key cryptosystem, but there is a need for public-key directories. a) What is a public-key certificate? What is the problem with public-key directories that certificates address? b) In general, public-key cryptosystems are not fast enough for users who need to exchange long streams of traffic. How can they be used in conjunction with symmetric-key cryptosystems, which are faster, in order to send long streams securely?

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