Question

Which of the following is a difference between trithemius cipher and vigenere cipher?

(a) they use different tables for encryption

(b) vigenere cipher is poly alphabetic whereas running key cipher is mono alphabetic

(c) vigenere cipher uses a key whereas no key is required for using trithemius cipher

(d) vigenere cipher is substitution cipher whereas trithemius cipher is transposition cipher

The question was asked during an interview.

Enquiry is from Cryptography in section Cryptography of Data Structures & Algorithms II

Answer 1

Right option is (c) vigenere cipher uses a key whereas no key is required for using trithemius cipher

Best explanation: Trithemius cipher is a special case of vigenere cipher. The difference is that vigenere cipher uses a different key every time but a fixed key is used by trithemius cipher.