Consider an application that requires an encryption and MAC algorithm be implemented on a processor with a small amount of non-volatile memory. The only cryptographic algorithm that the processor can compute is Triple-DES. But you have space for one 168-bit key. Describe how it is possible to both encrypt and MAC using only a single key. Justify your answer and state any assumptions you use.
Using a small non-volatile memory will require the key to be externally generated so that they can be amassed on the non-volatile memory (Gilardi and Serpanos, 2006). Since the key size is 168bits, the keys will be entered manually rather than being generated dynamically. The keys also have to be generated randomly (Gilardi and Serpanos, 2006).
What common usage do hash functions have in connection with digital signatures?
Hash functions are used to convert long messages and generate a distinct output value form the content of the message (Stewart and Chapple 2012). This output value is referred is the message digest and is used to implement a digital signature algorithm. Hash functions and digital signatures functions as data integrity checks. According to Kim and Solomon (2010), hashes create or form the fingerprint of the data. The hash is used as a reference to check whether the data was compromised or not. For example, hash references are provided by software developers so that customers can be able to check the integrity of the software they purchase. Digital signatures also ensure that the integrity of the messages sent is not compromised. The digital signatures link the identity of an entity to a particular piece of information. Thus, any malicious modifications in the messages or content sent are not compromised using hash functions and digital signatures.
References
Giladi, R., & Serpanos, D. N. (2006).Security and embedded systems. Amsterdam: IOS Press.
Kim, D., & Solomon, M. G. (2010).Fundamentals of Information Systems Security. London:
Jones & Bartlett Publishers.
Stewart, J. M., & Chapple, M. (2012).CISSP Certified Information Systems Security Professional
Study guide, sixth edition (6th Ed.). Indianapolis, Ind.: John Wiley & Sons.
