Text Encryption and Decryption in Notepad

# 1. Introduction to Text Encryption and Decryption

## 1.1 Concepts of Encryption and Decryption
In the realm of information security, encryption typically refers to the process of converting plaintext into ciphertext to protect the confidentiality of data, preventing unauthorized access and theft. Decryption, on the other hand, is the process of restoring ciphertext to plaintext, allowing the information to be understood and utilized by legitimate users.

Encryption mainly includes two methods: symmetric and asymmetric encryption:
- **Symmetric Encryption**: The same key is used for both encryption and decryption, which is fast, but key transmission and management can be complex.
- **Asymmetric Encryption**: Uses a pair of public and private keys for encryption and decryption, offering high security but at a slower speed.

## 1.2 The Importance of Text Encryption
Text encryption is a crucial aspect of information security, as it protects sensitive data from unauthorized access or theft. In the internet age, a vast amount of information transmission and storage relies on encryption technology to ensure the integrity and confidentiality of information. Moreover, text encryption is widely applied in various fields, such as network communication, file transfer, financial transactions, etc., to ensure data security against attacks.

# 2. Introduction to Notepad

Notepad is a text editor in the Windows operating system, although its functions are simple, it is very practical in text editing.
Let's take a closer look at the functional overview of Notepad and its applications in text editing.

### 2.1 Functional Overview of Notepad

Notepad is a lightweight text editor primarily used for viewing and editing text files, with the following main features:
- Provides basic text editing functions such as copy, paste, cut, etc.
- Supports various encoding formats, such as ANSI, UTF-8, etc.
- Conveniently creates and edits various text files, such as code files, configuration files, etc.

### 2.2 Applications of Notepad in Text Editing

Notepad has a wide range of applications in text editing, for example:
- Editing code files: Notepad can be used to edit HTML, CSS, JavaScript, and other code files.
- Creating configuration files: Notepad can be used to edit various configuration files, such as ini configuration files.
- Viewing and editing text logs: Notepad can be used to open and edit various log files, facilitating viewing and analysis.

### 2.3 Examples of Notepad Related Operations

Here is an example of using Notepad to edit text files:

# Create a text file and write content
with open("example.txt", "w") as ***
     ***"Hello, this is an example text.")

# Read and print file content
with open("example.txt", "r") as ***
     ***
     ***

These are simple application examples of Notepad in text editing, and through these functions, Notepad plays an important role in daily text editing.

# 3. Using Notepad for Text Encryption

In this chapter, we will详细介绍 how to use Notepad for text encryption. During the text encryption process, we need to choose the appropriate encryption algorithm and follow certain steps. Here are the details:

1. **Detailed steps for encrypting text**:
- Open the Notepad text editor.
- Input the text content to be encrypted.
- Choose an appropriate encryption algorithm.
- Perform the encryption operation on the text content.
- Save the encrypted text file.

2. **Choice and application of encryption algorithms**:
The following table lists commonly used encryption algorithms and their characteristics:

| Encryption Algorithm | Characteristics |
| -------------------- | ---------------- |
| AES | Symmetric encryption algorithm, high security, fast speed |
| RSA | Asymmetric encryption algorithm, suitable for key exchange during data transmission |
| DES | Symmetric encryption algorithm,已被AES替代, lower security |

3. **Example code**:
Below is a simple example code for text encryption using Python:

    # Import encryption module
    from Crypto.Cipher import AES
    import base64

    # Encryption function
    def encrypt_text(text, key):
        cipher = AES.new(key, AES.MODE_ECB)
        encoded = base64.b64encode(cipher.encrypt(text))
        return encoded

    # Input the text and key to be encrypted
    text = "Hello, World!"
    key = b'ThisIsASecretKey'

    # Encrypt the text
    encrypted_text = encry