For this question, you are not allowed the use of any calculators, computers software, or any...

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For this question, you are not allowed the use of any calculators, computers software, or any other computing system of any kind. You must show all your work, to receive any marks. Finally, clearly circle your final answer to each question. (a) For each of the following ciphertexts, find the correct plaintext. Each plaintext is a single English word. (i) Encrypted using a Caesar cipher. The shift value is 7. The ciphertext is: xbhuabt [3 marks] (ii) Encrypted using a Vigenere cipher. The key value is "qubit". The ciphertext is: sinxnjuuqhd (b) (i) The number 2143 is prime. Calculate 52145 mod 2143 (ii) Calculate 373,755,967,102 x 389,291,774,965 mod 100. [3 marks] [6 marks] [6 marks] (iii) Calculate 5-1 mod 11 (the multiplicative inverse of five modulo eleven). [6 marks] (iv) Calculate 764 mod 3 (seven to the power sixty-four modulo three). [6 marks] For this question, you are not allowed the use of any calculators, computers software, or any other computing system of any kind. You must show all your work, to receive any marks. Finally, clearly circle your final answer to each question. (a) For each of the following ciphertexts, find the correct plaintext. Each plaintext is a single English word. (i) Encrypted using a Caesar cipher. The shift value is 7. The ciphertext is: xbhuabt [3 marks] (ii) Encrypted using a Vigenere cipher. The key value is "qubit". The ciphertext is: sinxnjuuqhd (b) (i) The number 2143 is prime. Calculate 52145 mod 2143 (ii) Calculate 373,755,967,102 x 389,291,774,965 mod 100. [3 marks] [6 marks] [6 marks] (iii) Calculate 5-1 mod 11 (the multiplicative inverse of five modulo eleven). [6 marks] (iv) Calculate 764 mod 3 (seven to the power sixty-four modulo three). [6 marks]