# Vigenère cipher · Concept

> A substitution cipher that shifts each letter by a key word's letters in turn.

Source: https://mysteriesdept.com/concepts/CPT0DECW00CABZA/vigenere-cipher  
Publisher: Mysteries Department  
Licence: CC BY 4.0 (credit Mysteries Department and link the page)  

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[Concepts](https://mysteriesdept.com/concepts)Vigenère cipher

Concept · cryptography · in 1 mystery

# Vigenère cipher

A substitution cipher that shifts each letter by a key word's letters in turn.

[Kryptos](https://mysteriesdept.com/mysteries/kryptos)

The classic polyalphabetic cipher: each letter of the plaintext is shifted by the corresponding letter of a repeating key word. Kryptos K1 and K2 are Vigenère ciphers with a keyed alphabet, solved in the 1990s. Its weakness is the repeat, which period tests find; its descendants on this site, running-key and Gromark ciphers, were built to remove it.

## Where it comes up

**[Kryptos](https://mysteriesdept.com/mysteries/kryptos)**

K1 and K2 are Vigenère ciphers on a tableau keyed with KRYPTOS; K3 is a transposition.

## Cite it

```
Mysteries Department. (2026). Vigenère cipher [Concept CPT0DECW00CABZA]. https://mysteriesdept.com/r/CPT0DECW00CABZA
```

Key

**CPT** 0DECW00CABZA

Record

Concept

Field

Cryptography

Related

[Keyed alphabet](https://mysteriesdept.com/concepts/CPT0DECW00PYYD3/keyed-alphabet) · [Running-key cipher](https://mysteriesdept.com/concepts/CPT0DECW006275C/running-key-cipher) · [Gromark cipher](https://mysteriesdept.com/concepts/CPT0DECW00HS0D8/gromark-cipher)

Version

2

Added by

[apollo](https://mysteriesdept.com/u/apollo)

[ Wikidata](https://www.wikidata.org/wiki/Q190633)

**How this page is made.** The definition is the site's, in its own words. “Where it comes up” is read from the answers, methods and evidence that name the concept.

Related concepts

[Keyed alphabet](https://mysteriesdept.com/concepts/CPT0DECW00PYYD3/keyed-alphabet)[Running-key cipher](https://mysteriesdept.com/concepts/CPT0DECW006275C/running-key-cipher)[Gromark cipher](https://mysteriesdept.com/concepts/CPT0DECW00HS0D8/gromark-cipher)

The record

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[JSON](https://mysteriesdept.com/api/v1/records/CPT0DECW00CABZA)