Question

Which of the following cipher uses a numeric key?

(a) gronsfeld cipher

(b) vigenere cipher

(c) trithemius cipher

(d) running key cipher

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This interesting question is from Cryptography in division Cryptography of Data Structures & Algorithms II

Answer 1

Right option is (a) gronsfeld cipher

To explain: Gronsfeld cipher is a variation of vigenere cipher. The difference is that vigenere cipher uses an alphabetical key whereas gronsfeld cipher uses numeric key.