Cryptography

Cryptography is the art of hiding messages. People change regular words into codes that only the right people can read. This keeps secrets safe from strangers. It has been used for thousands of years. Today, cryptography keeps our computers and phones safe too.

Old-Time Secret Codes

Long ago, kings and generals used codes to send secret messages. Julius Caesar used a simple code where he shifted each letter by a few places. During World War II, a German machine called the Enigma made codes that were very hard to break. Smart mathematicians worked hard to crack them. That work helped end the war.

Codes Today

Modern cryptography uses tricky math to make codes. When you buy something online, your credit card number is turned into a code. Only the right computer can change it back to read it. This stops strangers from stealing your information. Text messages and passwords also use cryptography to stay private.

Fun Facts

• The word 'cryptography' comes from Greek words meaning 'hidden writing'.
• Spies sometimes hide messages inside pictures, which is called steganography.
• Breaking the Enigma code helped the Allies win World War II.

Did You Know?

Every time you visit a website with a little lock symbol, cryptography is busy protecting your connection.