Encryption facts for kids

Encryption is a way to hide information so that only certain people can read it. It's like putting a secret message into a locked box. You need a special key or password to open the box and read the message. When information is hidden this way, we say it is encrypted.

Decryption is the opposite of encryption. It's how you change the hidden, encrypted information back into its original, readable form. This original form is called "plaintext." The study of how to make and break codes is called cryptography. Sometimes, simple codes can be broken by hand, but more complex ones usually need powerful computers to figure out the secret key. Decryption is an important part of computer science and math.

How Encryption Works

Encryption uses a secret code, also called a "cipher," to scramble information. Imagine you have a message like "HELLO." An encryption method might change each letter to a different one. For example, 'H' could become 'K', 'E' could become 'H', and so on. The person who receives the scrambled message needs to know the secret rule (the key) to unscramble it back to "HELLO."

Simple Code Examples

One easy way to encrypt words is called ROT13. In ROT13, each letter in the alphabet is swapped with the letter 13 places after it. For example:

• 'A' becomes 'N'
• 'B' becomes 'O'
• 'C' becomes 'P'

So, if you encrypt "Simple English Wikipedia" using ROT13, it turns into "Fvzcyr Ratyvfu Jvxvcrqvn". This code is very easy to break. If you apply ROT13 a second time, you get the original message back!

Another old code is the Caesar cipher, used by Julius Caesar. This cipher shifts each letter by a certain number of positions, often 3. So, 'A' would become 'D', 'B' would become 'E', and so on.

Modern Encryption Methods

Most modern encryption methods are much more complicated than ROT13 or the Caesar cipher. This makes them very hard to break without the correct key. Some methods are designed just for text, while others can encrypt any kind of computer data, like pictures, music, or videos.

Today, two common and strong encryption systems are:

• RSA: This is an "asymmetric" system, meaning it uses two different keys – one for encrypting and one for decrypting. It's widely used for securing computer files.
• AES: This is a "symmetric" system, meaning it uses the same key for both encrypting and decrypting. It's also very common and strong.

The Unbreakable One-Time Pad

Most encryption methods can theoretically be broken, given enough time, powerful computers, and smart people. However, there's one special type of encryption called the one-time pad that is impossible to crack if used correctly.

To make a one-time pad truly unbreakable, you must follow three strict rules:

• Key Length: The secret key (password) must be as long as the message you want to encrypt. If your message has 50 letters, your key must also have at least 50 letters.
• Random Key: The secret key must be completely random. It can't be a word or a pattern. For example, "KQBWLDA..." is random.
• Single Use: The secret key can only be used once. If you want to send another message, you must use a brand new, different key.

If these three rules are followed, it's impossible for anyone to read your secret message without having the exact secret key. Because of this, during the Cold War, many embassies and military groups used one-time pads to send secret messages to their governments. They used small books filled with random letters or numbers, and each page could only be used once.

Encryption on the Internet

Encryption is super important for keeping your information safe when you use the Internet. Many websites use it to protect private details like your passwords, credit card numbers, or personal messages.

When you see "https://" at the beginning of a website address, the "s" stands for "secure." This means the website is using encryption to protect your connection. Some common encryption methods and protocols used on the Internet include:

• Secure Sockets Layer (SSL) and Transport Layer Security (TLS): These are widely used to secure web browsing and other internet communications.
• IPsec: This helps secure communications over internet networks.
• SSH: This is used for secure remote access to computers.

These systems often use strong encryption like RSA to keep your data safe as it travels across the internet.

Images for kids

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  A robot representing technology and security.