I bet the rules are wrong.
instead of:
Quote:

By default, a Vigenere cipher is using a simple Caesar shift. The modifed Vigenere cipher will add an offset to the encrypted characters on a per-word basis corresponding to the wordnumber in the sentence. Thus, the first word is using an offset of one, the second word is using an offset of two, and so on. For example encrypted character 'A' with word-offset '1' (first word) results in 'B', and encrypted letter 'b' with word-offset '2' (second word) results in 'C'.





it should be:
Quote:

By default, a Vigenere cipher is using a simple Caesar shift. The modifed Vigenere cipher will add an offset to the encrypted characters on a per-word basis corresponding to the wordnumber in the sentence. Thus, the first word is using an offset of one, the second word is using an offset of two, and so on. For example encrypted character 'A' with word-offset '1' (first word) results in 'B', and encrypted letter 'b' with word-offset '2' (second word) results in 'd'.




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