1.) DSA specifies that if the signature generation process results in a value of s=0,  a new value of k should be generated and the signature should be recalculated. Why?

2.) Section 12.6 listed three general approaches to authenticated encryption: A →E, E →A, E +A. 

a.) Which approach is used by CCM?

b.) Which approach is used by GCM?

3.) If F is an error-detection function, either internal or external use (Figure 12.2) will provide error-detection capability. If any bit of the transmitted message is altered, this will be reflected in a mismatch of the received FCS and the calculated FCS, whether the FCS function is performed inside or outside the encryption function. Some codes also provide an error-correction capability. Depending on the nature of the function, if one or a small number of bits is altered in transit, the error-correction code contains sufficient redundant information to determine the errored bit or bits and correct them. Clearly, an error-correction code will provide error correction capability when used external to the encryption function. Will it also provide this capability if used internal to the encryption function?

4.) What are the core components of a PKI? Briefly describe each component.

5.) Explain the problems with key management and how it affects symmetric cryptography.