# Keyed alphabet · Concept

> A cipher alphabet that starts with a key word and continues with the letters not yet used.

Source: https://mysteriesdept.com/concepts/CPT0DECW00PYYD3/keyed-alphabet  
Publisher: Mysteries Department  
Licence: CC BY 4.0 (credit Mysteries Department and link the page)  

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[Concepts](https://mysteriesdept.com/concepts)Keyed alphabet

Concept · cryptography · in 2 mysteries

# Keyed alphabet

A cipher alphabet that starts with a key word and continues with the letters not yet used.

[Voynich Manuscript](https://mysteriesdept.com/mysteries/voynich-manuscript)[Kryptos](https://mysteriesdept.com/mysteries/kryptos)

An alphabet written out with a key word first (repeated letters dropped) and the remaining letters following in order. Kryptos uses one keyed by KRYPTOS on the sculpture's right-hand panel, and the readings of K4 that work start from it. A keyed alphabet turns a guessable shift into one that needs the word.

## Where it comes up

**[Voynich Manuscript](https://mysteriesdept.com/mysteries/voynich-manuscript)**

The substitution changes with position in the line (a line-keyed or position-keyed alphabet), so that the same plaintext at the same offset in different lines appears as glyph-disjoint isomorphs.

[The substitution changes with position in the line (a line-keyed or position-keyed…](https://mysteriesdept.com/mysteries/voynich-manuscript/answers/ANS0D8FZXXA51CM/the-substitution-changes-with-position-in-the-line-a-line)[Word-as-letter, periodic transposition, position-keyed alphabets, single nulls and sorted…](https://mysteriesdept.com/mysteries/voynich-manuscript/evidence/EVD0D8GDPB24104/word-as-letter-periodic-transposition-position-keyed)

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

K4 uses a Gromark-type cipher (a keyed alphabet with a running numeric key generated by chain addition) or a close relative.

[K4 uses a Gromark-type cipher (a keyed alphabet with a running numeric key generated by chain addition) or a…](https://mysteriesdept.com/mysteries/kryptos/answers/ANS0D7HTBYY64KH/k4-uses-a-gromark-type-cipher-a-keyed-alphabet-with-a)

## Cite it

```
Mysteries Department. (2026). Keyed alphabet [Concept CPT0DECW00PYYD3]. https://mysteriesdept.com/r/CPT0DECW00PYYD3
```

Key

**CPT** 0DECW00PYYD3

Record

Concept

Field

Cryptography

Related

[Vigenère cipher](https://mysteriesdept.com/concepts/CPT0DECW00CABZA/vigenere-cipher) · [Gromark cipher](https://mysteriesdept.com/concepts/CPT0DECW00HS0D8/gromark-cipher)

Version

2

Added by

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

**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

[Vigenère cipher](https://mysteriesdept.com/concepts/CPT0DECW00CABZA/vigenere-cipher)[Gromark cipher](https://mysteriesdept.com/concepts/CPT0DECW00HS0D8/gromark-cipher)

The record

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[JSON](https://mysteriesdept.com/api/v1/records/CPT0DECW00PYYD3)