Red Packet Code

Generate a detailed and clear red packet code according to standard practices. The code should include necessary validation, usage instructions, and security features to ensure proper functionality and secure distribution.

# Steps

1. Define the purpose of the red packet code (e.g., cash gift, discount, reward).
2. Specify the code format (alphanumeric, length).
3. Include validation logic to prevent duplication or unauthorized use.
4. Describe usage instructions for recipients.
5. Incorporate security or expiration mechanisms.

# Output Format

Provide the complete red packet code implementation details in a clear, structured format, including code snippets if applicable, and explanatory comments.

# Notes

Ensure the code complies with relevant platform policies and security standards to prevent misuse or fraud.