Definition of Vigenère cipher
: polyalphabetic substitution with alphabets derived from one pair of primary alphabets by sliding (as in the Vigenère tableau) for which the usual keying formula is P+K=C where P is the position of the plaintext letter in the plain component, C that of the ciphertext letter in the cipher sequence, and K that of the key letter in the normal alphabet and where positions are numbered from 0 to 25 and 26 is subtracted from sums above 25 — compare beaufort cipher, progressive-alphabet cipher
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Origin and Etymology of vigenère cipher
after Blaise de Vigénère †1596 French diplomat and student of cryptography
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