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Atbash Cipher

The Atbash cipher is a simple substitution cipher where each letter is replaced by its mirror image in the alphabet: A becomes Z, B becomes Y, C becomes X, and so on. It is a symmetric cipher (self-inverse), meaning applying it twice returns the original text.

10Worksheets
200+Practice Questions
BeginnerDifficulty
1 hourHours to Master

What You'll Learn

Introduction & Overview Why This Matters How to Solve Pro Tips & Tricks
Shortcut Methods Common Mistakes Practice Worksheets Exam Importance

Introduction to Atbash Cipher

The Atbash cipher is a simple substitution cipher where each letter is replaced by its mirror image in the alphabet: A becomes Z, B becomes Y, C becomes X, and so on. It is a symmetric cipher (self-inverse), meaning applying it twice returns the original text.

Prerequisites

Alphabet positions (A=1 to Z=26) Understanding of mirror concept Formula: mirror_position = 27 - original_position
Why This Matters: Atbash Cipher problems appear in 1-2 questions in SSC CGL and Banking PO exams. They test understanding of alphabet symmetry.

How to Solve Atbash Cipher Problems

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Step 1: Identify each letter in the given word

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Step 2: Convert the letter to its position number (A=1, B=2, ..., Z=26)

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Step 3: Apply the Atbash formula: mirror_position = 27 - original_position

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Step 4: Convert the mirror position back to a letter

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Step 5: Write the mirror letters in the same order to form the encoded/decoded word

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Step 6: Since Atbash is self-inverse, the same process decodes as well

Pro Strategy: Memorize common Atbash pairs: A↔Z, B↔Y, C↔X, D↔W, E↔V, F↔U, G↔T, H↔S, I↔R, J↔Q, K↔P, L↔O, M↔N. Practice with short words like 'HOLD' (SLOW) and 'WIZARD' (DRAZIW).

Example Problem

Example: Decode 'GSV' using Atbash cipher. Solution: Step 1: G=7, S=19, V=22 Step 2: Mirror: 27-7=20→T, 27-19=8→H, 27-22=5→E Step 3: Decoded word: THE Answer: THE

Pro Tips & Tricks

  • Atbash is its own inverse: applying it twice returns the original message
  • The sum of positions of a letter and its Atbash mirror is always 27
  • M (13) mirrors to N (14) - the middle pair
  • Common words: 'HOLD' → 'SLOW', 'WIZARD' → 'DRAZIW', 'BLAH' → 'YOZS'
  • Vowels map to: A→Z, E→V, I→R, O→L, U→F (not vowels)
  • The word 'ATBASH' encodes to 'ZGYHZS'

Shortcut Methods to Solve Faster

mirror_letter = chr(27 - (ord(letter) - ord('A') + 1) + ord('A') - 1)
Use the pair list: A↔Z, B↔Y, C↔X, D↔W, E↔V, F↔U, G↔T, H↔S, I↔R, J↔Q, K↔P, L↔O, M↔N
For any letter, its mirror is the letter at position (27 - original_position)

Common Mistakes to Avoid

Using 26 - position instead of 27 - position (off by one error)
Reversing the order of letters instead of mirroring each letter individually
Forgetting that Atbash applies to each letter independently
Confusing Atbash with reverse cipher (reversing word order)

Exam Importance

Atbash Cipher is an important topic for various competitive exams. Here's how frequently it appears:

SSC CGL
1-2 questions
BANKING PO
1-2 questions
RAILWAYS RRB
1-2 questions
CAT
0-1 questions
INSURANCE
1-2 questions

Ready to Master Atbash Cipher?

Start with Worksheet 1 and work your way up to expert level! Each worksheet includes:

20 practice questions
Detailed solutions
Step-by-step explanations
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