Last Reserve
This demanding Checkerboard challenge gives you little excess evidence and no reason to trust an early guess. Bring patience, discipline, and a willingness to test every useful pos…
Cipher Hub
Classical cipher challenges with a Workbench for analysis, transformation, and hypothesis testing.
Newest Cipher Challenges
Narrow Margin
This compact Checkerboard challenge leaves less room for easy certainty. Precision matters: small observations carry more weight, and an assumption made too quickly can steer the w…
Crossing Lines
Several plausible lines of attack present themselves in this mid-level Checkerboard challenge. Keep competing ideas in play, compare what each one explains, and be ready to revise…
Measured Steps
This Checkerboard challenge offers enough material for steady progress, but it rewards disciplined bookkeeping. Work methodically, test each observation, and expect the answer to e…
First Bearings
A generous stretch of ciphertext makes this an approachable first Checkerboard challenge. Take your time, keep clear notes, and use the room it gives you to build confidence as you…
The State Department's Dam Dispatch
The U.S. State Department printed this 25-codeword dispatch in 1876 as an official worked example of its message system. It is authentic period training material, not a sent telegr…
Roosevelt's Orders to Dewey
Assistant Secretary of the Navy Theodore Roosevelt sent this 21-codeword cable to Admiral George Dewey in Hong Kong on 26 February 1898. The received codewords are preserved. Fried…
The Jacksonville Number Telegram
This 48-group telegram was sent from Jacksonville to Samuel Pasco and E. M. L'Engle on 17 November 1876. Its complete two-digit payload is presented without the clear heading and s…
The Jacksonville Digraph Telegram
A telegram sent from Jacksonville to George P. Raney on 16 November 1876 enciphered its main body as 120 two-letter groups. The clear closing sentence and signature are not include…
The Gabble Telegram
This dictionary-code telegram was sent from Portland, Oregon, to Samuel J. Tilden's circle during the disputed presidential election on 1 December 1876. All 31 transmitted words ar…
Frailey's Challenge to Poe
Physician Charles S. Frailey challenged Edgar Allan Poe with this mixed-symbol cryptogram in 1841. The period printing substituted available type characters consistently for the ci…
S.D.L.'s Second Challenge
S.D.L.'s second cryptogram appeared beside the first in Poe's July 1841 article. The surviving challenge is substantial but ends before its final sentence is complete. Period trans…
S.D.L.'s First Challenge
A correspondent signing as S.D.L. submitted this three-paragraph cryptogram from Stonington, Connecticut, and Edgar Allan Poe printed it in the July 1841 issue of *Graham's Magazin…
Fish's Coded Cable to Schenck
Secretary of State Hamilton Fish sent this mixed clear-and-code cable to diplomat Robert C. Schenck on 16 June 1872. Its 26 variable-length code elements remain embedded in the cle…
Grant's Richmond Telegram
This operational telegram, transmitted by Samuel Beckwith for Ulysses S. Grant on 3 April 1865, reached the War Department in a reversed and phonetically altered form. All 40 trans…
Rosecrans to Burnside
Union major general William S. Rosecrans sent this long routed telegram to Ambrose Burnside during the Chattanooga campaign on 16 October 1863. Editorial running word counts are om…
Buell's September 30 Telegram
Don Carlos Buell sent this second routed telegram to Henry W. Halleck on 30 September 1862. All 51 transmitted words, including routing material and nulls, are retained. Friedman's…
Buell's September 29 Telegram
Union major general Don Carlos Buell sent this 61-word routed telegram to Henry W. Halleck on 29 September 1862. Its ordinary-looking words include routing material and nulls. Frie…
Pemberton's Vicksburg Telegram
Confederate lieutenant general John C. Pemberton sent this mixed clear-and-cipher telegram to Joseph E. Johnston from Vicksburg on 26 December 1862. The source preserves mistakes i…
Patterson's Challenge to Jefferson
Robert Patterson sent this challenge cipher to Thomas Jefferson on 19 December 1801 and declared that it would resist the ingenuity of the whole human race. Its 40 transmitted line…
Lovell's Cipher to Francis Dana
James Lovell sent these enciphered passages to American diplomat Francis Dana on 6 January 1781. The 85 number groups appear within a longer clear-text letter. Federal historical e…
Lovell's Cipher to John Adams
James Lovell sent this numeric passage to John Adams on 2 January 1781 amid the Continental Congress's military and financial difficulties. The 41 groups are isolated from the lett…
Franklin's Cipher to Dumas
Benjamin Franklin sent this enciphered passage to the American diplomat Charles W. F. Dumas on 16 August 1781. The surrounding clear words have been omitted, leaving the 69 transmi…
The Papal Nuncio's Brussels Letter
A papal nuncio in Brussels sent this coded letter to Rome on 9 October 1721. The manuscript mixes mostly two-digit groups with nulls and a few four-digit nomenclature entries. Tran…
The Petrograd Negotiations Telegram
General Miller sent this telegram during 1919 negotiations over a proposed Finnish and White Russian operation against Petrograd. The 1,400-character message uses irregular columna…
Rabenhaupt's Encrypted Letter
Karel Rabenhaupt ze Suché sent this encrypted letter to Landgravine Amalie Elisabeth during the Thirty Years' War in June 1646. Its 369 cipher units, originally separated by dots a…
The D'Agapeyeff Challenge Cipher
Alexander D'Agapeyeff printed these 79 five-digit groups as the final challenge in the first edition of *Codes and Ciphers* in 1939. No accepted decipherment is known, and an error…
Perwich's Paris Dispatch
English diplomat William Perwich sent this encrypted dispatch from Paris on 9 April 1670. Pipes preserve the cells and empty padding of the National Archives' 22-row transcription,…
Tyler's Cryptograph to Poe
A letter signed W. B. Tyler challenged Edgar Allan Poe with this symbol cipher in *Graham's Magazine* in December 1841. The source's text transcription uses Þ and ⊥ for two inverte…
Thomson's Albanian Telegram
This 736-group telegram was intercepted during the 1914 international mission in Albania associated with Dutch general Lodewijk Thomson. Its surviving transmission contains genuine…
Arthur Dee's Alchemical Cipher
Arthur Dee concealed a passage in his alchemical manuscript *Hermeticae Philosophiae medulla*, now British Library Sloane MS 1902. This is the complete text-native transcription st…
Elgar's Dorabella Cipher
Edward Elgar sent Dora Penny an 87-symbol note in July 1897. The letters below are neutral labels for its 20 observed symbol shapes; repeated labels represent repeated shapes. No s…
The Zimmermann Telegram
German Foreign Secretary Arthur Zimmermann sent this coded telegram in January 1917 for transmission to Mexico. The 153 groups below reproduce the Washington-to-Mexico copy held by…
Shelves for Everyone
A biographical account of a neighborhood organizer who built a reading room from borrowed shelves, donated books, and persistent local support.
Instruments in Small Hands
A biographical sketch of a teacher who made scientific instruments affordable enough for ordinary classrooms.
Voices After Midnight
A biographical sketch of a radio producer who preserved local voices rarely heard on national broadcasts.
The Orchard Doctor
A biographical account of a plant pathologist who helped small orchards recognize disease before harvests failed.
A Map of Footsteps
A biographical sketch of a walking-route researcher whose observations changed how a city planned crossings and pavements.
The Reluctant Conductor
A biographical account of an ensemble director known for careful rehearsals, modest programs, and little interest in celebrity.
The Clockmaker’s Window
A short fictional narrative about an apprentice who notices that one repaired clock behaves differently from every other clock in the shop.
The Train at Platform Zero
A short fictional narrative about a station announcement for a platform that does not appear on any public map.
A Parcel for Winter
A short fictional narrative about a misdirected package that passes through several households during the first snowfall.
The Room Above the Bakery
A short fictional narrative about two tenants who communicate through the noises, warmth, and aromas moving between floors.
When the Streetlights Blinked
A short fictional narrative about neighbors coordinating an ordinary evening after a fault darkens one block at a time.
The Borrowed Umbrella
A short fictional narrative following an umbrella through a chain of accidental exchanges across a rainy town.
The Fourth Key
A short fictional narrative about a caretaker who inherits three labeled keys and one key with no recorded purpose.
A Message in Blue Ink
A short fictional narrative about a note discovered inside a returned library book and the cautious search for its intended reader.
Why the Wren Hides
An original folktale explaining why a small bird chooses dense hedges instead of competing for the tallest branches.
The Bell Beneath the Hill
An original legend about a buried bell said to ring when villagers ignore a promise made to the river.
The Baker and the North Wind
An original folktale about a baker who bargains with the wind to protect a winter market.
How the Lake Found Its Name
An original place-name legend built around travelers who mistake an echo for an answer.
The Fox at the Ferry
An original animal tale about a fox who repeatedly crosses a river without paying the ferryman’s unusual toll.
The Stone That Remembered
An original legend about a boundary stone that preserves agreements after the people who made them are gone.
Three Knocks at Harvest
An original seasonal tale about a custom of leaving the final sheaf untouched until three knocks are heard.
The Lantern in the Reeds
An original marsh legend about a wandering light that rewards careful listeners and misleads impatient travelers.
The Committee for Quiet Pens
A comic account of an office committee formed to investigate one pen that clicks louder than the others.
Instructions for Losing a Hat
A humorous procedural guide for misplacing a hat efficiently and recovering everything except the hat.
The Unofficial Queue
A comic account of strangers creating elaborate rules for a line before anyone knows what the line is for.
A Highly Efficient Meeting
A humorous report on a meeting devoted entirely to reducing the number and length of future meetings.
Notes from the Pigeon Desk
A comic workplace memo about pigeons treating a public information counter as their regional office.
The Emergency Teapot
A humorous account of a workplace emergency plan that is excellent except for its disputed tea provisions.
An Expert in Wrong Doors
A comic profile of a visitor who confidently enters every incorrect room and somehow improves each event.
The Annual Sock Audit
A humorous report on a household inventory that becomes more rigorous as its subject becomes less important.
From the End of the Line
A personal letter written from the final stop of a long tram route after an unexpected afternoon journey.
A Note Before the Thaw
A letter between old friends about plans that must wait until roads, gardens, and tempers have softened.
To the Keeper of Room Twelve
A formal letter thanking an unknown caretaker for preserving a small but important shared space.
Postmarked Tuesday
A practical family letter whose ordinary errands gradually reveal a significant change at home.
The Unsent Recommendation
A candid recommendation letter revised by someone struggling to balance honesty, loyalty, and useful praise.
From a Bench by the Sea
A reflective letter describing the view, conversations, and small decisions observed from one public bench.
To My Future Neighbor
A welcoming letter left for the next resident of an apartment, including practical knowledge that no lease records.
The Second Narrator
A literary discussion of stories in which a quiet observer gradually becomes more important than the apparent hero.
A Door Left Unnamed
A literary essay about how omitted descriptions can make a setting more active in a reader’s imagination.
Reading the Empty Chair
A literary essay about absent characters whose influence is felt through objects, habits, and other people’s speech.
The Minor Character’s Revenge
A literary discussion of minor characters who expose the limits of a central character’s understanding.
A Chapter Without Weather
A literary essay about environmental description, including what changes when a narrative deliberately avoids it.
Turn the Kettle Down
Original song lyrics about a late conversation that becomes easier after the room grows quiet.
Northbound Morning
Original song lyrics following an early train through industrial streets, fields, and pale winter light.
Cardboard Moon Parade
Original song lyrics about neighbors building a nighttime parade from inexpensive materials and shared work.
Leave the Porch Light Low
Original song lyrics about offering guidance without demanding that a traveler stop or explain.
Five Miles of River
Original song lyrics tracing one river through working land, suburbs, bridges, and tidal water.
Under the Fallen Log
A natural-history account of the organisms and changing conditions found beneath a fallen woodland log.
The Tide Pool at Noon
A natural-history account of how tide-pool animals endure heat, evaporation, waves, and sudden exposure.
A Meadow After Mowing
A natural-history account of how mowing changes shelter, flowers, insects, and feeding opportunities across a meadow.
Rain Between the Pines
A natural-history account of how rainfall is intercepted, redirected, stored, and released within a pine woodland.
The Life of a Public Bench
An explanatory account of how a public bench is selected, installed, maintained, moved, and eventually replaced.
Why Streets Keep Their Curves
An explanatory account of historical property lines, terrain, transport, and engineering decisions preserved in street layouts.
What a Seed Library Lends
An explanatory account of seed libraries, including collection, labeling, viability, and the meaning of returning seed.
How Lost Property Travels
An explanatory account of how transport systems record, sort, store, identify, and dispose of lost belongings.
The Work Behind Clean Water
An explanatory account of the sampling, treatment, monitoring, and maintenance behind a dependable water supply.
When a Building Changes Use
An explanatory account of the structural, legal, and practical work involved in adapting an old building for a new purpose.
A Measure of Enough
A philosophical argument about sufficiency, ambition, and the difficulty of deciding when improvement should stop.
The Honest Shortcut
A philosophical reflection on shortcuts that preserve a task’s purpose and shortcuts that merely hide unfinished work.
When Rules Become Habits
A philosophical argument about the difference between following a rule deliberately and acting from an established habit.
The Value of an Unfinished Task
A philosophical reflection on whether incomplete work can retain value independent of its intended result.
Inventory of Morning
An original poem cataloguing the ordinary sounds, objects, and movements that accumulate during an early morning.
After the Market Closes
An original poem about the traces left behind when traders, customers, and temporary stalls depart.
Small Weather
An original poem observing minor changes in air, light, moisture, and temperature within one street.
The Guest Without a Chair
An original long-form riddle whose answer is an ordinary presence that enters rooms without needing a seat.
A House with No Door
An original long-form riddle describing a familiar enclosure that has walls but no entrance.
The Thief That Gives
An original long-form riddle whose answer removes one thing while making another easier to perceive.
A River You Can Fold
An original long-form riddle about a useful representation that behaves unlike the thing it depicts.
The Garden Underground
An original long-form riddle about a branching system that grows away from light.
The Memory of Ice
A scientific explanation of how ice cores preserve layered evidence about earlier atmospheres and environments.
A Signal Through Fog
A scientific explanation of how different wavelengths, droplets, and instruments affect communication through fog.
Why Soap Lifts Grease
A scientific explanation of how soap molecules interact with water, oils, surfaces, and mechanical motion.
The Slow Work of Rust
A scientific explanation of iron corrosion and the roles of water, oxygen, salts, coatings, and contact with other metals.
How Seeds Sense Spring
A scientific explanation of dormancy, moisture, temperature, light, and chemical signals in seed germination.
When Bacteria Share
A scientific explanation of several ways bacteria exchange genetic material and how that affects populations.
A Case for the Last Bus
An original civic speech arguing that late public transport supports workers, families, and a safer city.
Opening the Community Workshop
An original opening speech establishing shared responsibilities in a public workshop.
Welcome to the Night Shift
An original workplace speech recognizing the distinct responsibilities and knowledge of overnight staff.
Before We Rebuild the Square
An original public speech asking residents to judge a redesign by everyday use as well as appearance.
For the Small Museum
An original advocacy speech explaining why modest local collections deserve skilled care and stable support.
The Unspaced Letter
An intercepted letter has lost every word boundary. Its numerical coordinate labels are unfamiliar, and its square is not alphabetical.
Signal in the Noise
A dense scientific passage removes spacing and replaces the usual digits with unrelated letter labels. Repeated coordinate pairs and language statistics must carry most of the solv…
The Mathematics of Waiting
An explanatory account of queues, arrival patterns, service rates, and why waiting time often feels unpredictable.
Margins of the Old Edition
A literary essay about marginal notes that create a conversation among readers separated by several decades.
The Shape of a Promise
A philosophical reflection on what makes promises binding when circumstances, abilities, or relationships change.
Instructions to a Shadow
An original poem addressing a shadow as an unreliable companion through changing light.
The Window Counts Birds
An original poem using a window’s fixed viewpoint to record birds and passing seasons.
The Useful Doubt
A philosophical reflection on doubt as a tool for better judgment rather than a reason to avoid every decision.
The Return of the Swifts
A natural-history account of migrating swifts, their urban nesting sites, and the timing of their seasonal return.
The Traveler Who Stays
An original long-form riddle about something that crosses great distances while remaining in one place.
The Patient Lichen
A natural-history account of lichens growing on stone, bark, roofs, and other surfaces under difficult conditions.
The Clock Without Hands
An original long-form riddle describing a process that marks intervals without a conventional clock face.
A Toast to Patient Work
An original ceremonial speech celebrating work whose value appears through reliability rather than spectacle.
Coordinates 101
A guided first encounter with a five-by-five coordinate square. Standard numerical labels and preserved word spacing keep the focus on reconstructing the square.
Tracks After Rain
A medium-length passage keeps its word boundaries, but the coordinate labels are alphabetic and the pair order is reversed. Use repetition before committing to a square.
The Locked Room
A compact riddle with familiar numerical labels and preserved word breaks. Recover the square, then answer the question hidden in the coordinates.
The Archive Dispatch
A long archival dispatch uses custom letter labels, reversed coordinate order, and no spacing. The key is withheld; solve from pair frequencies, repeated fragments, and reconstruct…
The Workbench Waltz
Original song lyrics that turn patient repair, scattered tools, and repeated attempts into a dance.
Inside a Repair Café
An explanatory account of volunteer repair events and the practical limits of fixing unfamiliar household objects.
Before the First Tram
An original poem about workers, lights, and quiet preparations in the hour before public transport begins.
Brass and Dust
An original poem about handled metal, workshop residue, and the slow evidence of repeated use.
A Map Made of Sound
An original poem locating a neighborhood through bells, engines, voices, footsteps, and water.
The Quiet Surveyor
This Challenge presents a biographical sketch of a municipal surveyor whose patient fieldwork shaped a growing city while her name remained largely unknown.
My first Playfair
This is a Playfair cipher, so analyze fixed digraphs rather than single letters. Read the Ciphertext as pairs at positions 1–2, 3–4, and so on; never move those boundaries. Use Pai…
My first Columnar transposition
This is a columnar transposition: the characters are unchanged, but whole vertical slices have been rearranged. Ignore the displayed groups of five. Make a structural guess by test…
My first Variant Beaufort
This is a repeating-key Variant Beaufort cipher. Begin by estimating the period from repeated-sequence spacings, then inspect the corresponding Periodic columns. Each column uses o…
My first Gronsfeld
This is a Gronsfeld cipher: a repeating sequence of digits applies Caesar shifts, one digit per position. Use Repeated sequences and their spacings to propose the digit-string leng…
My first Beaufort
This is a repeating-key Beaufort cipher. First estimate the period with Repeated sequences: record several repeat spacings and test a divisor shared by more than one. Split the Cip…
My first Vigenère
This is a repeating-key Vigenère cipher. Begin with a Key-length guess, not a keyword guess. Open Repeated sequences, record the spacings between repeated groups, and test a common…
My first Patristocrat
This is a Patristocrat: it uses one consistent cipher-to-plain substitution, but it removes all original spaces and punctuation. Ignore the displayed groups of five; they are not w…
My first Aristocrat
This is an Aristocrat: one cipher letter always represents one different plaintext letter, with word divisions and punctuation preserved. Make the first guess from a word pattern,…
My first Caesar
This is a Caesar cipher: every letter has moved by one fixed shift. Do not begin by running all 26 shifts. Use the preserved spaces and punctuation to make a plaintext guess: a one…
Who Owns a Memory
A philosophical argument about shared memories, conflicting accounts, privacy, and the limits of personal ownership.
In Defense of Public Shade
An original civic speech arguing for trees, shelters, and shaded routes in hotter urban summers.
The Name You Cannot Keep
An original long-form riddle about a label that changes as soon as its condition becomes true.
What We Owe the Future
A philosophical argument about obligations to people who will live with decisions they could not influence.
The Kiln Keeper
A biographical account of a ceramic artist whose career combined production, repair, and decades of teaching.
The Weight of a Comma
A literary discussion of punctuation choices that alter pace, emphasis, and the apparent confidence of a narrator.
The Library at Closing Time
A literary reflection on libraries as settings where private reading and public life continuously overlap.
Night Shift in the Orchard
A natural-history account of nocturnal animals that visit orchards for food, shelter, or prey.
Where the Dunes Begin
A natural-history account of the grasses, wind, salt, and drifting sand that establish coastal dunes.
The longest words
There are a lot of strange very long words found in dictionaries.
Regarding the Missing Atlas
A politely escalating letter to a library about an atlas that everyone remembers borrowing differently.
Copper in the Rain
Original song lyrics connecting the sound of rainfall with old pipes, roofs, and remembered houses.
Small Hours, Open Windows
Original song lyrics about the overlapping sounds heard in a neighborhood before dawn.
Measuring an Invisible Wind
A scientific explanation of instruments and indirect observations used to measure air movement.
The Physics of a Bent Spoon
A scientific explanation of reflection from curved surfaces and why familiar shapes appear distorted.
The Graduation Nobody Expected
An original graduation speech for learners who completed a course after delays, interruptions, and changed plans.
Reading Repeated Shapes
An introductory Aristocrat tutorial focused on repeated words and repeated-letter patterns.
Frequencies Without Certainty
An introductory Aristocrat tutorial focused on using frequency evidence without turning it into automatic substitutions.
Managing Competing Guesses
An introductory Aristocrat tutorial focused on recording, comparing, and revising multiple hypotheses.
Finishing an Aristocrat
An introductory Aristocrat tutorial focused on moving from a partial mapping to a checked complete Solution.
Working Without Word Divisions
An introductory Patristocrat tutorial focused on analyzing substitution text without visible word boundaries.
Finding Structure in Five-Letter Groups
An introductory Patristocrat tutorial explaining why printed groups are presentation units rather than plaintext words.
Finishing a Patristocrat
An introductory Patristocrat tutorial focused on validating a nearly complete Solution when spacing must also be restored.
Testing a Short Word
An introductory Aristocrat tutorial focused on testing short-word hypotheses across the whole Ciphertext.
The aristocrat
An Aristocrat is a monoalphabetic simple-substitution cipher that preserves word divisions and punctuation. The name comes from the American Cryptogram Association, founded in 1930…
The Archive of Small Things
This Challenge examines how museums document and preserve ordinary objects, and how provenance determines what can reliably be said about them.
The Measure of a Storm
This Challenge explains how consistent weather observations become useful long-term records and how changes in instruments and methods affect those records.
Before the Curtain Rises
This Challenge follows the backstage work required to coordinate scenery, props, lighting, sound, and performers during a theatrical production.
The Forest’s Invisible Market
This Challenge describes the relationships among tree roots, fungi, microorganisms, and soil, including how nutrients move through a forest.
The Language of Knots
This Challenge examines how knots are used for fastening, measurement, recordkeeping, decoration, and communication.
Beneath the Cobblestones
This Challenge explores how pipes, cables, tunnels, foundations, and abandoned structures accumulate beneath city streets.
The Borrowed Voice
This Challenge explains how early sound recordings are preserved and restored, including the difficulty of reducing damage without altering the original performance.
Lines That Refuse to Stay Still
This Challenge looks at how rivers and coastlines change over time and how surveyors and cartographers keep maps accurate.
The Night Garden
This Challenge explores nocturnal pollinators, the plants that attract them, and the practical choices involved in creating a garden that supports them.
The Last Lantern
This Challenge examines how lighthouse lenses, lamps, and rotating mechanisms are maintained in buildings exposed to salt, wind, and changing weather.
A Question of Habit
General simple substitution, presented in the Aristocrat format. Each ciphertext letter consistently represents one different plaintext letter. Word divisions and punctuation are r…
The Surveyor’s Hidden Order
Surveyors turn a landscape into rows, columns, coordinates, and measured intervals. A transposition cryptogram reverses that convenience: every symbol remains present, but the stru…
The Stagehand’s Secret
A stage illusion can depend less on making something vanish than on moving familiar pieces while attention is elsewhere. Keyed columnar transposition works in that spirit. The mess…
The Telegraph Table
Before encryption became electronic, a clerk could protect a dispatch with nothing more than a pencil, a key, and a ruled sheet. In keyed columnar transposition, the message is wri…
The Misordered Columns
Keyed columnar transposition. This method rearranges positions rather than substituting symbols. A writer prepares the text, writes its Transposition Units across a rectangular gri…
Progress by degrees
In a Patristocrat, word divisions and punctuation are removed before the Ciphertext is regrouped in fives. Each ciphertext letter consistently represents one different plaintext le…
Across the board
A message waits behind the grid.
The Hidden Square
Polybius cipher. Each two-digit group identifies one cell in a 5 × 5 square: row first, then column. Rows and columns are numbered 1–5, I and J share one cell, and `/` marks a word…
A Matter of Pairs
Playfair cipher. Standard Playfair transforms fixed pairs of letters rather than single letters. It uses a 5 × 5 square containing the alphabet with I and J sharing one position. R…
The Rise of the Codebreakers
Adapted from Wikipedia's “History of cryptography” under CC BY-SA 4.0; changes were made.
Secrets Before Paper
Adapted from Wikipedia's “History of cryptography” under CC BY-SA 4.0; changes were made.
Keykeykey
This is a simple demo of a vigenère cipher.
The Indecipherable Cipher
Vigenère cipher.
The Shifting Dispatch
Caesar cipher.
Found Text
A short text was copied without context.
My First Baconian
Each carrier letter belongs to class A or B, and every five carrier letters form one Solution letter. The word READ begins the Solution. Place that crib at position 1, then carry t…
A Matter of Pairs
Francis Bacon’s biliteral cipher conceals one message inside another by assigning every carrier letter to class A or B. Each group of five carrier letters represents one plaintext…