# Homophonic substitution · Concept

> A cipher in which one plaintext letter can be written as any of several cipher signs.

Source: https://mysteriesdept.com/concepts/CPT0DECVZY0W38A/homophonic-substitution  
Publisher: Mysteries Department  
Licence: CC BY 4.0 (credit Mysteries Department and link the page)  

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[Concepts](https://mysteriesdept.com/concepts)Homophonic substitution

Concept · cryptography · in 4 mysteries

# Homophonic substitution

A cipher in which one plaintext letter can be written as any of several cipher signs.

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

A substitution cipher that gives the common letters several cipher signs each, so that the cipher text no longer shows the plaintext's letter frequencies. It defeats plain frequency counting, which is why so many of the unread texts on this site have been tested against it: a text whose signs are more numerous than any alphabet, and whose frequencies are flatter than any language's, looks the way a homophonic cipher looks. Breaking one needs more text and a model of the language underneath, or a key.

## Where it comes up

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

The text is a known language under a homophonic/verbose cipher (several ciphertext units per plaintext letter), units being glyphs, slot-fillers, BPE tokens or whole words.

[A known language under a homophonic cipher](https://mysteriesdept.com/mysteries/voynich-manuscript/answers/ANS0D8FZT8445MD/a-known-language-under-a-homophonic-cipher)[A published mechanical procedure produced it](https://mysteriesdept.com/mysteries/voynich-manuscript/answers/ANS0D8FZZ4C2TD3/a-published-mechanical-procedure-produced-it)[Period practice as a re-spaced stream gives the closest held-out fit to the herbal pages yet](https://mysteriesdept.com/mysteries/voynich-manuscript/evidence/EVD0DCBGX09MT6M/period-practice-as-a-re-spaced-stream-gives-the-closest-held)[No simulated procedure reproduces the statistics](https://mysteriesdept.com/mysteries/voynich-manuscript/evidence/EVD0D8GDQ2G7EGT/no-simulated-procedure-reproduces-the-statistics)[Endings are more concentrated than Italian's](https://mysteriesdept.com/mysteries/voynich-manuscript/evidence/EVD0D8GDS106H27/endings-are-more-concentrated-than-italians)[Homophonic substitution of five languages fails](https://mysteriesdept.com/mysteries/voynich-manuscript/evidence/EVD0D8GDP383XD5/homophonic-substitution-of-five-languages-fails)

**[Zodiac ciphers](https://mysteriesdept.com/mysteries/zodiac-ciphers)**

[Z340 showed the writer added transposition and irregularities to homophonic substitution.](https://mysteriesdept.com/mysteries/zodiac-ciphers/evidence/EVD0D71PJ3E3KHB/z340-showed-the-writer-added-transposition-and)

**[Copiale cipher](https://mysteriesdept.com/mysteries/copiale-cipher)**

The manuscript is a homophonic substitution cipher for eighteenth-century German, with Roman letters as spaces, and the published key reads the whole text.

[The manuscript is a homophonic substitution cipher for eighteenth-century German, with Roman letters as…](https://mysteriesdept.com/mysteries/copiale-cipher/answers/ANS0CYVFJCE19GS/the-manuscript-is-a-homophonic-substitution-cipher-for)[A long text (75,000 characters), a known cipher type (homophonic substitution) and a natural language that a…](https://mysteriesdept.com/mysteries/copiale-cipher/answers/ANS0CYVFM347M49/a-long-text-75-000-characters-a-known-cipher-type-homophonic)

## Methods that use it 1

[Fifteenth-century cipher practices as one fitted family, per section](https://mysteriesdept.com/methods/MTH0DCB5D15DB6M/fifteenth-century-cipher-practices-as-one-fitted-family-per)

MTH

## Cite it

```
Mysteries Department. (2026). Homophonic substitution [Concept CPT0DECVZY0W38A]. https://mysteriesdept.com/r/CPT0DECVZY0W38A
```

Key

**CPT** 0DECVZY0W38A

Record

Concept

Field

Cryptography

Related

[Nomenclator](https://mysteriesdept.com/concepts/CPT0DECVZZ6JH82/nomenclator) · [Transposition cipher](https://mysteriesdept.com/concepts/CPT0DECVZZD5M0G/transposition-cipher) · [Frequency analysis](https://mysteriesdept.com/concepts/CPT0DECVZZJW77N/frequency-analysis)

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Related concepts

[Nomenclator](https://mysteriesdept.com/concepts/CPT0DECVZZ6JH82/nomenclator)[Transposition cipher](https://mysteriesdept.com/concepts/CPT0DECVZZD5M0G/transposition-cipher)[Frequency analysis](https://mysteriesdept.com/concepts/CPT0DECVZZJW77N/frequency-analysis)

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