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Cipher Decoding - Expert Level: vigenere cipher EXPERT

Strategic basic drills ★ for cipher decoding: 20 expert-level problems. Worksheet 29 of 30 - Focus: vigenere cipher. Develop expertise in cryptography, encryption patterns, shift ciphers with step-by-step solutions. Ideal for expert-level learners targeting challenging problems and time-bound practice.

📝 Worksheet 29 of 30 • 20 questions • ⏱️ Estimated time: 20 minutes • 🎯 Expert level

What you'll learn in this worksheet:
Your progress through Cipher Decoding
Worksheet 29 of 30 (96% complete)

Question 1

Using Playfair cipher with keyword 'KEY', encode: 'HAND'
Playfair with keyword 'KEY': HAND → GBLG
playfair, digraph

Question 2

Using book cipher with 'Olympic Sports' [RUNNING, SWIMMING, GYMNASTICS, BOXING, FENCING, ARCHERY, SKATING...] (6 pages, 10 words), decode positions: (pg2, w10), (pg5, w6), (pg1, w1), (pg2, w4)
Position decoding: ROWING ARCHERY RUNNING BOXING
book, position

Question 3

Using keyword cipher with keyword 'ISLAND', decode: 'LIQ'
Cipher alphabet: ISLANDBCEFGHJKMOPQRTUVWXYZ
Decoding LIQ → CAR
keyword, substitution

Question 4

Using Vigenère cipher with keyword 'PLANET', encode: 'CENTURY'
Vigenère: CENTURY with key 'PLANET' → RPNGYKN
vigenere, polyalphabetic

Question 5

Using Rail Fence cipher with 5 rails, encode: 'BRAIN'
Rail Fence (5 rails): BRAIN → BRAIN
railfence, transposition

Question 6

Using reverse cipher (writing backwards), decode: 'ECNASSIANER'
Reverse cipher: ECNASSIANER reversed is RENAISSANCE
reverse, backwards

Question 7

Using Hill cipher with key matrix [[3, 2], [5, 7]], encode: 'LION'
Hill cipher: LION → XHQF
hill, matrix

Question 8

Decode the Base64 string: 'U1lTVEVN'
Base64 decoding: U1lTVEVN → SYSTEM
base64, hex, encoding

Question 9

Using Baconian cipher (5-bit binary encoding), decode: '01110 00010 00100 00000 01101'
Baconian decoding: 01110 00010 00100 00000 01101 → OCEAN
baconian, binary

Question 10

In Morse code, what does '-. .. -. .' represent?
Morse decoding: NINE → -. .. -. .
morse, dots-dashes

Question 11

Using date-based cipher with date 17-07-2021 (sum of day+month+year = 17), decode: 'RJKVIFZU'
Date-based cipher: Shift = 17, RJKVIFZU decoded → ASTEROID
date, calendar

Question 12

Using Vigenère cipher with keyword 'NONCE', decode the ciphertext: 'OFBYR'
Vigenère: With key 'NONCE', OFBYR → BROWN
vigenere, polyalphabetic

Question 13

Using Columnar Transposition cipher with key 'KEY', encode: 'FIREWALL'
Columnar Transposition with key 'KEY': FIREWALL → IWLFELRA
transposition, columnar

Question 14

Using Atbash cipher (A↔Z, B↔Y, C↔X...), decode: 'SATELLITE'
Atbash: SATELLITE → HZGVOORGV
atbash, mirror

Question 15

Using Autokey cipher with initial key 'KEY', encode: 'STAR'
Autokey cipher: STAR with key 'KEY' → CXYJ
autokey, vigenere

Question 16

Using reverse cipher (writing backwards), decode: 'ERTAEHT'
Reverse cipher: ERTAEHT reversed is THEATRE
reverse, backwards

Question 17

Using Vigenère cipher with keyword 'HILL', encode: 'FUNCTION'
Vigenère: FUNCTION with key 'HILL' → MCYNAQZY
vigenere, polyalphabetic

Question 18

Using Playfair cipher with keyword 'PYTHON', encode: 'BEYOND'
Playfair with keyword 'PYTHON': BEYOND → NGTPAN
playfair, digraph

Question 19

Using Atbash cipher (A↔Z, B↔Y, C↔X...), decode: 'ETHEREUM'
Atbash: ETHEREUM → VGSVIVFN
atbash, mirror

Question 20

Using the same Caesar cipher that encodes 'ICE CREAM' as 'YSUJSHUQC', decode: 'LYHKI'
Shift = 16. LYHKI decoded (shift -16) = VIRUS
caesar, shift
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