How to Recognise Cipher Families

The Four Major Cipher Families

Before you can decode a message, you need to identify what type of cipher you're dealing with. Most ciphers fall into four main families, each with distinct characteristics:

1. Substitution Ciphers — Letters are replaced with other letters or symbols
2. Transposition Ciphers — Letters are rearranged but not changed
3. Encoding Systems — Text converted to numbers, binary, or other formats
4. Visual/Symbol Ciphers — Letters represented by shapes, flags, or images

1. Recognising Substitution Ciphers

Visual Tells

• Text looks like random letters but maintains word structure (spaces preserved)
• Punctuation often remains in place
• Single-letter words appear (likely "A" or "I")
• Common word patterns visible (2-letter, 3-letter groupings)

Frequency Analysis

Use our Letter Frequency Analyzer to count letter occurrences. In English:

• E, T, A, O, I, N are the most common letters
• If one letter dominates, it likely represents E
• The letter "Q" almost always precedes "U"

Sub-Types to Check

2. Recognising Transposition Ciphers

Visual Tells

• Letter frequency matches normal English — the same letters are there, just scrambled
• No obvious word boundaries (spaces often removed)
• Text may be arranged in a grid or specific pattern
• Length is usually preserved exactly

Key Identifier

Run the ciphertext through our Letter Frequency Analyzer. If the frequency distribution looks like normal English (E is most common, etc.), you're dealing with transposition, not substitution.

Sub-Types to Check

3. Recognising Encoding Systems

Visual Tells

• Numbers only — likely A1Z26, ASCII, or coordinate-based
• Only 0s and 1s — binary encoding
• Only 0-7 — octal
• 0-9 and A-F — hexadecimal
• Alphanumeric with = padding — Base64

Quick Identification

4. Recognising Visual & Symbol Ciphers

Visual Tells

• Dots and dashes — Morse code
• Raised dots in 2×3 grid — Braille
• Grid-based angular shapes — Pigpen cipher
• Flag positions — Semaphore
• Stick figures in positions — Dancing Men cipher

Common Symbol Systems

Quick Decision Tree

Use this flowchart to quickly identify your cipher type: