Encryption

01

What is it?

Encryption transforms readable data, called plaintext, into a protected form called ciphertext.

Encryption protects information by making it unreadable without the right key.

02

Think of it like...

Think of putting a message inside a locked box before sending it.

Readable message

Anyone holding the original message can read it.

Locked box

The message is transformed into protected ciphertext.

Right key

The intended reader uses a key to recover the message.

03

What does it do?

Encryption helps protect the confidentiality of data while it is stored or moving between systems.

Protects content

Unreadable ciphertext hides the original meaning from unintended readers.

Uses keys

A key controls how data is encrypted and how an authorized reader decrypts it.

Supports trust

Secure systems can exchange sensitive information with less risk of exposure.

04

Where is it used?

Encryption is used wherever sensitive information needs protection.

Web traffic

HTTPS encrypts data sent between a browser and a server.

Stored data

Databases, backups, and files can be encrypted at rest.

Messaging

Messages can be encrypted while they travel between participants.

Payments

Payment details are protected during transmission and storage.

Credentials

Secrets and tokens can be protected when systems exchange them.

Devices

Phones and computers can encrypt local storage if a device is lost.

05

Example

A client sends a password reset token to a server over an encrypted HTTPS connection.

Readable before protection

reset_token=7f3a...&user=42

Protected while travelling

The network carries ciphertext. The authorized endpoint decrypts it before processing.

06

How it connects

Plaintext

Encrypt with key

Ciphertext

Decrypt with key

Encryption protects the data; the key and the access controls determine who can recover it.

07

Do Not Confuse

Designed to be reversible for an authorized reader with the right key.

Hashing

Produces a one-way digest used for comparison, integrity checks, or password verification.

Encryption is for protected recovery. Hashing is for one-way comparison.

08

Topic Glossary

ENGLISH TERM	中文	SIMPLE ENGLISH	中文小白理解
Encryption	加密	Turning readable data into protected data.	把可读数据转换成受保护的数据。
Decryption	解密	Turning protected data back into readable data.	把受保护的数据还原成可读数据。
Plaintext	明文	Data in its readable form before encryption.	加密前人能够直接读懂的数据。
Ciphertext	密文	Protected data produced by encryption.	加密后看起来无法直接理解的数据。
Key	密钥	A value used to encrypt or decrypt data.	用来加密或解密数据的一段关键值。
Symmetric Encryption	对称加密	Encryption that uses the same key to encrypt and decrypt.	加密和解密使用同一把密钥的方式。
Asymmetric Encryption	非对称加密	Encryption that uses a public key and a private key.	使用公钥和私钥的一对密钥进行保护的方式。
Encryption at Rest	静态数据加密	Encryption that protects stored data.	保护数据库、文件或备份等已存储数据的加密。
Encryption in Transit	传输中加密	Encryption that protects data while it moves between systems.	保护数据在系统之间传输过程的加密。

09

What to Remember

Encryption turns readable data into protected ciphertext.

The right key is needed to decrypt the data.

Encryption protects confidentiality, but it does not replace authentication or authorization.