Question

what will be the plain text corresponding to cipher text "PROTO" if vigenere cipher is used with keyword as "HELLO"​

Answer 1

The answer is "INDIA".

Explanation:

• In the question some choices were missing, that's why we only defined the correct choice.    

• The Vigenere is the cipher, and the type of polyalphabetic partial replacement, that helps to make the use of the vigenere menu or the table, in the plain text.  
• This same chart shows which "India", that is in the plain text, that's why in this question the answer is "INDIA".

Learn more:

• Find output: https://brainly.in/question/15179430