How humanity evolved from preserving messages in stone to protecting information with modern cryptography — told as one story, in three chapters.
3chapters
1000+years apart
1same problem: trust
START THE STORY →
CHAPTER ONE
🏛️ Temple
The first permanent records — carved for anyone to see, for centuries.
ENTER →
CHAPTER TWO
🟫 Copper Plate
Durable, portable, and sealed — a record that could travel and be authenticated.
ENTER →
🔐
CHAPTER THREE
🔐 Modern Cryptography
Secrets made mathematical — how encryption hides a message from everyone but its intended reader.
ENTER →
CHAPTER ONE
When stone became a record
Before computers, databases and cloud storage, people still had the same problem we have today: how can we preserve an important message so that people in the future can trust it? One answer began with a chisel.
WHY WERE TEMPLE WALLS USED?
Permanent by design
Temples were not only places of worship — their walls could also become permanent records. Donations, land grants, temple administration and other official matters could be engraved directly into stone.
Stone was valuable for one simple reason: it lasted. A spoken message could be forgotten. A temporary document could disappear. But an inscription carved into a temple wall could remain visible for generations.
👑
King / Donor
Makes an important decision
↓
🏛️
Temple authority
The institution stands behind the record
↓
✍️
Information
The decision is put into words
↓
🪨
Engraved in stone
Words become a permanent inscription
↓
👥
Publicly visible
Anyone can walk up and read it
↓
🔎
Future verification
Later generations can check the claim
A REAL HISTORICAL EXAMPLE
The Brihadeeswarar Temple
The Brihadeeswarar Temple at Thanjavur, built under Rajaraja Chola I around 1010 CE, contains inscriptions that preserve information about temple administration, donations, land and resources.
📜
👑
🪨
🔍 EXPLORE THE INSCRIPTION
Click a marker on the inscription to see what it represents.
TAP A MARKER
Select 📜, 👑 or 🪨 on the image to begin.
BUT IS THIS REALLY CRYPTOGRAPHY?
The first clue to cryptography
Temple inscriptions were generally not secret messages. Their purpose was usually preservation and public record-keeping, not hiding information. Temple inscriptions were not modern cryptography — they were an early solution to the broader problem of creating trustworthy records.
But they introduced an idea that would later become central to information security: how do we know this record is genuine, and how do we know it has not been changed?
"How do we know this record is genuine, and how do we know it has not been changed?"
🪨
Ancient method
Physical permanence
🔐
Modern method
Cryptographic integrity
The problem stayed. The technology changed.
TRY IT YOURSELF
Tamper with the record
Unlike editing a digital document, changing an inscription requires physically altering the stone.
ORIGINAL RECORD
"Land granted to the temple."
What security idea does this resemble?
TEMPLE QUIZ
Check your understanding
1. Why was stone useful for important records?
2. What was the main purpose of many temple inscriptions?
3. Which modern security idea is closest to protecting a record from unnoticed modification?
4. Were temple inscriptions modern cryptography?
← BACK TO START
CONTINUE THE STORY: COPPER PLATES →
CHAPTER TWO
A record that could travel
Stone was permanent. But permanence came with a problem: a temple wall could not easily travel with you. What if an important legal record needed to be carried, stored, or presented somewhere else? Enter the copper plate.
WHY COPPER?
Durable, and portable
Copper plates provided a durable and more portable surface for recording important grants and official information. They could be engraved, preserved and transported — something a temple wall never could be.
A bound set of copper plates
Stone
Copper
Permanent
Durable
Publicly visible
Portable
Fixed location
Can be stored
Difficult to move
Easier to preserve and present
THE SEAL
The signature before digital signatures
A seal could be associated with a ruler, authority or institution. It helped people identify the source of a document and provided a visible sign of authenticity.
Every letter had to be individually engraved — a slow, deliberate process that made forgery difficult.
🔏
👑 RulerAuthorises an official grant
📜 Official grantThe decision is put into writing
🟫 Copper plateThe grant is engraved onto metal
🔏 SealAn identifying mark is stamped
✔️ AuthenticationThe source of the record becomes verifiable
🔎 Future verificationThe plate can later be presented as evidence
Click the button to stamp the seal onto the plate.
Ancient seal → modern digital signature. They are not the same technology, but they address a related question: can we verify where this record came from?
THE HIDDEN RECORD
From engraving to discovery
Click through each stage to see what happened to a copper-plate grant over time.
COPPER QUIZ
Check your understanding
1. Why were copper plates useful?
2. What could a seal help establish?
3. What modern concept is loosely comparable to an authenticated seal?
4. Why was portability important?
← BACK: TEMPLE
NEXT: HOW DO WE VERIFY A RECORD HASN'T BEEN CHANGED? →
A temple used physical stone. A copper plate used a pressed seal. But as communication developed, a different problem appeared: what if a message should be understood only by the intended person? That's where encryption comes in.
PLAINTEXT
KING NEEDS THE WEAPON
🔐
ENCRYPTED MESSAGE
[encrypted result]
🔑
INTENDED RECEIVER
Uses the correct key to recover the message
LIVE ENCRYPTION DEMO
Try the Caesar cipher
Enter a message, pick a shift key, and watch each letter move that many positions through the alphabet.
— run ENCRYPT to see the result —
FROM SIMPLE CIPHERS TO MODERN CRYPTOGRAPHY
Where it went from here
Simple substitution methods such as the Caesar cipher are useful for understanding the basic idea of encryption, but they are not secure enough for modern communication.
From here, cryptography kept modernizing — moving from hand ciphers to complex mathematical algorithms that computers use to protect everything from bank transactions to private messages. Today's systems rely on problems that are easy to compute one way but nearly impossible to reverse without the right key, letting the same core idea — hide the message, share the key — scale to a fully digital world.
MODERN CRYPTOGRAPHY QUIZ
Check your understanding
1. What is encryption used for?
2. In the Caesar Cipher demo, what does the key control?
3. What does DECRYPT do to an encrypted message?
4. Why isn't the Caesar cipher secure enough for modern use?
← BACK: COPPER PLATE
SEE THE WHOLE STORY →
THE SAME HUMAN PROBLEM — A NEW TECHNOLOGY
🏛️
Temple
"Preserve the record."
↓
🟫
Copper
"Preserve + authenticate the record."
↓
🔐
Cryptography
"Protect and verify information mathematically."
From something carved into stone… to something protected by mathematics.
